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Simple Summary: Positive natural selection increases the frequency of beneficial genetic variations, promoting an organism's adaptability and survival in specific environments. In this study, we conducted whole-genome resequencing and population genetic structure analysis to investigate the genetic diversity of Zaobei cattle, local yellow cattle from China. By comparing Zaobei cattle with Simmental cattle, we identified several genomic regions exhibiting positive selection. Gene annotation of these regions revealed key traits of Zaobei cattle, such as heat tolerance, fertility, and superior meat quality. These findings not only help understand the characteristics of Zaobei cattle but also provide valuable genetic information for future breeding programs, thereby improving their production efficiency and economic value. This investigation provides a comprehensive analysis of genomic diversity and selection signatures in Zaobei beef cattle, an indigenous breed known for its adaptation to hot and humid climates and superior meat quality. Whole-genome resequencing was conducted on 23 Zaobei cattle, compared with 46 Simmental cattle to highlight genetic distinctions. Population structure analysis confirmed the genetic uniqueness of Zaobei cattle. Using methods such as DASDC v1.01, XPEHH, and θπ ratio, we identified 230, 232, and 221 genes through DASDC, including hard sweeps, soft sweeps, and linkage sweeps, respectively. Coincidentally, 109 genes were identified when using XPEHH and θπ ratio methods. Together, these analyses revealed eight positive selection genes (ARHGAP15, ZNF618, USH2A, PDZRN4, SPATA6, ROR2, KCNIP3, and VWA3B), which are linked to critical traits such as heat stress adaptation, fertility, and meat quality. Moreover, functional enrichment analyses showed pathways related to autophagy, immune response, energy metabolism, and muscle development. The comprehensive genomic insights gained from this study provide valuable knowledge for breeding programs aimed at enhancing the beneficial traits in Zaobei cattle. [ABSTRACT FROM AUTHOR]

Simple Summary: Research on broiler feeding has increasingly focused on finding effective alternatives to antibiotic growth promoters (AGPs) due to concerns about antibiotic resistance and antibiotic residues in food products. A total EU-wide ban on AGPs was implemented in 2006. However, 70% of antibiotics are still used in animal treatment, contributing to 700,000 deaths worldwide annually due to antibiotic-resistant infections. As a result, researchers have sought natural alternatives, such as probiotics, prebiotics, enzymes, and plant-based preparations like essential oils, which have shown promise in improving broiler production traits and meat quality. The experiment in this study demonstrated that phytogenic supplements improved the European Production Efficiency Factor (EPEF). Additionally, meat from chickens on the phytogenic diet had better water-holding capacity, higher collagen content, and a favorable profile of amines, ketones, and aldehydes, indicating improved quality. These findings suggest that alternatives to AGPs can enhance broiler chicken production and meat physicochemical properties when used in appropriate doses and proportions. The primary objective of this study was to investigate the impact of a phytogenic additive (PA) in broiler chickens' diet on production, physiochemical parameters, and the profile of volatile organic compounds present in broiler chickens' meat. The experiment was conducted in a commercial chicken house, where Ross 308 broiler chickens were divided into two groups, each consisting of 65,000 broilers. One group was fed a diet supplemented with 100 ppm of PA throughout the rearing period. The primary chemical composition of the meat and its physicochemical parameters were determined. A visual assessment of breast muscles for defects and volatile organic compounds were evaluated using an electronic nose system. No statistically significant differences were shown in the production performance of the chickens; while summarizing all production parameters, a higher EPEF index of 31 points in the experimental group was highlighted. Breast muscle quality showed differences in drip loss and WHC (p ≤ 0.01) in favor of the experimental group, and a lower cutting force value (p ≤ 0.05) was found for breast muscles from the experimental group. The group also had a lower proportion of muscles with a white striping defect, and the results of volatile organic compound profiling showed the most aroma units. [ABSTRACT FROM AUTHOR]

Simple Summary: The widespread use of antibiotics in poultry production has raised public concerns about food safety and meat quality. This study investigated the effects of early ciprofloxacin use on Xueshan chickens, focusing on growth, meat quality, and metabolic changes. It was found that, while ciprofloxacin treatment did not affect overall chicken growth, it significantly altered meat quality characteristics, which may affect meat texture and preservability. Although ciprofloxacin residues were not detected in muscle, metabolic analyses revealed significant metabolic alterations, particularly in microbial and amino acid metabolism pathways. These findings emphasize that antibiotic use may have far-reaching effects on poultry product quality, involving not only direct meat quality changes but also complex metabolic reactions. This study provides new perspectives for understanding the role of antibiotics in poultry production, which is important for optimizing antibiotic-use strategies and ensuring food safety. The results may be an important reference for poultry producers, food safety regulators and consumers. To investigate the effects of early administration of ciprofloxacin (CIP) on Xueshan chickens, in this study Xueshan chickens were measured for growth performance, tested for drug residues, evaluated for meat quality, and muscle metabolism changes were explored using a non-target metabolomics approach. Experimental findings revealed that early CIP use did not significantly impact the overall growth rate of Xueshan chickens (p > 0.05). However, notable alterations in meat quality were observed: the CIP-treated group exhibited a significant decrease in muscle pH (pH1 and pH24) and a marked increase in drip loss and moisture content (p > 0.05). No CIP residues were detected in muscle tissue. Untargeted metabolomics analyses unveiled significant alterations in the metabolic profile of market-age chickens following CIP treatment. Both functional enrichment and metabolic network analyses indicated significant effects on the ko01120 (microbial metabolism in diverse environments) and ko00350 (tyrosine metabolism) pathways, implying that CIP treatment may influence chicken meat quality by modulating microbial communities and amino acid metabolism. This study provides a crucial foundation for understanding the impact of antibiotics on meat quality and metabolism in poultry production, offering scientific insights for optimizing antibiotic-use strategies and safeguarding poultry product quality. [ABSTRACT FROM AUTHOR]

Simple Summary: This study investigates how different housing systems affect daily step counts and their impact on body conformation, carcass traits, meat quality, and serum biochemical parameters of Jiuyuan Black chickens. Chickens were monitored from 60 to 150 days old, with step counts recorded using pedometers. The study showed that free-range chickens with high step counts had significantly higher daily and total steps compared to other groups, as well as higher heart weight, lower abdominal fat, and better meat quality, but lower intramuscular fat. The CK and LDH levels in chickens exhibited an almost consistent upward trend as exercise levels increased. Overall, free-range chickens with more exercise volume improved heart weight and reduced fat but negatively impacted some body measurements and meat quality. These findings help in choosing housing systems for Chinese indigenous chickens. This study aims to investigate the dynamic changes in daily step counts under different housing systems and further explore the effects of housing system on the body conformation, carcass traits, meat quality, and serum biochemical parameters of a Chinese indigenous chicken breed. At 60 d of age, 300 Jiuyuan Black male chickens with similar body weights in each housing system were further raised until the age of 150 d. At 90, 120, and 150 d of age, in both cage-reared and free-range systems, the top 20 chickens with the highest step counts measured using pedometers and the bottom 20 chickens with the lowest step counts were designated as the cage high-steps group (CHS), the cage low-steps group (CLS), the free-range high-steps group (FHS), and the free-range low-steps group (FLS), respectively. The results show that, at any age stage, the average daily steps (ADS) and total steps (TS) of the FHS group are significantly higher than the other three groups (p < 0.05). The TS of almost all groups showed an overall downward trend as the age increased. Increased exercise volume results in reduced shank length (90 d), breast width (90 d), and keel length (150 d) (p < 0.05). Only birds at 90 d of age from the FHS and FLS groups exhibited lower live body weight, carcass weight, half-eviscerated weight, eviscerated weight, breast muscle weight, leg muscle weight, and percentage of eviscerated weight than the CLS group (p < 0.05). Birds from the FHS group showed the highest heart weight values but the lowest abdominal fat weight values among these four groups (p < 0.05). Both the breast and leg muscle samples from the FHS group displayed higher dry matter and shear force than those from the CHS and CLS groups (p < 0.05). The FHS group displayed the lowest intramuscular fat among the four groups (p < 0.05). The creatine kinase (CK) and lactate dehydrogenase (LDH) levels in chickens of all age stages were almost observed to rise with increased physical activity. In conclusion, free-range chickens with more exercise volume exhibited an elevated heart weight and reduced abdominal fat but showed negative effects on some body measurements and carcass traits. These results can provide a theoretical basis for the selection of different housing systems for Chinese indigenous chickens. [ABSTRACT FROM AUTHOR]

Simple Summary: The slaughter of females represents a significant proportion of all cattle slaughtered in Brazil. Despite this, the number of studies on the quality of the carcasses and meat of these animals is still low, which leads to less knowledge about the quality and commercial value of the meat. The aim of this study was to evaluate the carcass and meat quality of heifers from different genetic groups fed diets containing different sources of nonprotein nitrogen. The main differences found were in relation to the genetic group, with effects on carcass weight, fat content in the carcass and meat, and also on the fatty acid profile of the meat. The aim of this study was to evaluate the effect of genetic groups and diets with different sources of nonprotein nitrogen (NPN) on the carcass and meat characteristics of beef heifers. The meat from 40 heifers (20 ½ Angus ½ Nellore (A × N) and 20 ½ Charolais ½ Nellore (L × N)), finished in feedlots, was used. The heifers were fed diets containing different sources of NPN—(1) a diet with livestock urea and protected urea (LPU) and (2) a diet with extruded urea (EU)—in a completely randomized design with a 2 × 2 factorial arrangement. Carcass, composition and meat quality evaluations were carried out. There were no significant interactions between diet and genetic group for most of the variables evaluated (p > 0.05). The A × N heifers had higher hot carcass weights (305.73 vs. 279.80 kg), loin eye areas (80.87 vs. 75.45 cm2), subcutaneous fat thicknesses (8.69 vs. 6.35 mm) and lower shear forces (6.98 vs. 7.7 kg) compared to the C × N heifers (p < 0.05). The meat from the A × N heifers had higher proportions of saturated fatty acids (49.41 vs. 47.95%), with no effects on the proportions of monounsaturated (47.57%) and polyunsaturated (4.01%) fatty acids. The A × N heifers had better carcass and meat characteristics, while the C × N heifers had meat and fat with better fatty acid profiles. [ABSTRACT FROM AUTHOR]

Simple Summary: Simple Summary: Poultry can be exposed to a number of adverse stimuli during the pre-slaughter handling. Noise, movement, lack of access to water and feed, change in habitat, disruption of flock hierarchy or environmental conditions can lead to adverse changes in the bird's body. A significant increase in these factors can cause disturbances in the body's homeostasis. These changes may be reflected in meat quality. Therefore, there is a need to assess the effect of pre-slaughter turnover on meat quality. In this study, the effects of pre-slaughter treatments on changes in macro- and micronutrient content were analyzed. In this study, the effect of pre-slaughter handling on the content of macro- and micronutrients in blood serum and in the breast muscle of turkeys was assessed. Four different variants of pre-slaughter handling were used in the research: no transport (N-T), transport for a distance of 100 km (T-100), transport for a distance of 200 km (T-200), and transport for a distance of 300 km (T-300). In each of them, 30 female and 30 male turkeys were used. Blood was collected from the birds before slaughter, and samples of the pectoral muscle were collected after slaughter. In the obtained biological material, the content of Mg, P, Ca, Fe, Na and K was analyzed. On the basis of the obtained research results, it can be concluded that the pre-slaughter handling negatively affects the content of macro- and microelements both in the blood serum and in the pectoral muscles of experimental turkeys. Additionally, differences due to the sex of birds were observed. [ABSTRACT FROM AUTHOR]

Simple Summary: Skeletal muscle fibers, the smallest functional unit of skeletal muscle, directly affect the normal growth and development of animal muscles and the quality of carcass muscle after slaughter. Individual characteristics, feeding, and genetic factors influence the heterogeneity of muscle fibers in livestock. Notably, genetic factors rapidly and efficiently improve the proportion and conversion of animal muscle fibers with the development of omics technology and sequencing technology. Therefore, only a global approach including all parameters seems to be pertinent to understand the relationships among the characteristics of myofibers, growth performance, and meat quality. The type of muscle fiber plays a crucial role in the growth, development, and dynamic plasticity of animals' skeletal muscle. Additionally, it is a primary determinant of the quality of both fresh and processed meat. Therefore, understanding the regulatory factors that contribute to muscle fibers' heterogeneity is of paramount importance. Recent advances in sequencing and omics technologies have enabled comprehensive cross-verification of research on the factors affecting the types of muscle fiber across multiple levels, including the genome, transcriptome, proteome, and metabolome. These advancements have facilitated deeper exploration into the related biological questions. This review focused on the impact of individual characteristics, feeding patterns, and genetic regulation on the proportion and interconversion of different muscle fibers. The findings indicated that individual characteristics and feeding patterns significantly influence the type of muscle fiber, which can effectively enhance the type and distribution of muscle fibers in livestock. Furthermore, non-coding RNA, genes and signaling pathways between complicated regulatory mechanisms and interactions have a certain degree of impact on muscle fibers' heterogeneity. This, in turn, changes muscle fiber profile in living animals through genetic selection or environmental factors, and has the potential to modulate the quality of fresh meat. Collectively, we briefly reviewed the structure of skeletal muscle tissue and then attempted to review the inevitable connection between the quality of fresh meat and the type of muscle fiber, with particular attention to potential events involved in regulating muscle fibers' heterogeneity. [ABSTRACT FROM AUTHOR]

Simple Summary: Concerns about animal welfare practices have increased as consumer awareness and regulatory standards have evolved. This study investigated the effects of lairage conditions on welfare and meat quality of pigs during lairage periods. A total of 3070 finishing pigs were assigned to one of six groups arranged in two trials in a 2 × 3 factorial design according to the illuminance (under 40 lux (LX), over 40 lux (HX)) and stocking density (low density (LD), higher than 0.83 m2/100 kg; normal density (ND), 0.50–0.83 m2/100 kg; high density (HD), lower than 0.50 m2/100 kg) with high temperature (HT), higher than 24 °C; low temperature (LT), lower than 10 °C. Based on the obtained results, stocking of too-high (lower than 0.50 m2/100 kg) density at HT and stocking of too-low (higher than 0.83 m2/100 kg) density at LT are generally not good for meat quality and animal welfare. This study investigated the effects of lairage conditions on the welfare and meat quality of pigs during lairage periods. A total of 3070 finishing pigs were assigned to one of six groups arranged in two trials in a 2 × 3 factorial design according to the illuminance (under 40 lux (LX), over 40 lux (HX)) and stocking density (low density (LD), higher than 0.83 m2/100 kg; normal density (ND), 0.50–0.83 m2/100 kg; high density (HD), lower than 0.50 m2/100 kg) with high temperature (HT), higher than 24 °C; low temperature (LT), lower than 10 °C. Pigs stocked with HD showed lower aggression behavior and overlap behavior than those stocked with LD at LT. Pigs stocked with HD showed higher standing, sitting, and aggression behavior than those stocked with LD at HT. Pigs stocked with HD showed higher pH than those stocked with LD at LT. At HT, pigs stocked with LD showed higher pH, WHC, DL, and CL than those stocked with HD. At LT, pigs stocked with LD showed higher cortisol levels than those stocked with HD. However, pigs stocked with LD showed lower cortisol levels than those stocked with HD at HT. Based on the obtained results, stocking of too-high (lower than 0.50 m2/100 kg) density at HT and stocking of too-low (higher than 0.83 m2/100 kg) density at LT are generally not good for meat quality and animal welfare. [ABSTRACT FROM AUTHOR]

Simple Summary: After approximately two decades of controlled breeding at the Shanghai Academy of Agricultural Sciences in China, Luchuan (LC) pigs have developed two distinct phenotypes: one with obesity (FLC) and the other with leanness (LLC). Since recent research suggests a link between microorganisms and the development of these different phenotypes, this study investigated the fecal microbiota profiles and serum metabolites of FLC and LLC pigs. We found significant changes in the microbiota and metabolites between the two groups. The correlation studies showed a significant link between the modified microbiota, metabolites, and the observed phenotypic differences in the LC pigs. Notably, Jeotgalicoccus was positively correlated with the body weight and chest circumference, but negatively correlated with certain metabolites like 2-mercaptobenzothiazole and N1-pyrazin-2-yl-4-chlorobenzamide, which were positively associated with Bacteroides. These findings provide strong evidence for a new connection between the gut microbiome, metabolome, and phenotypic variation in LC pigs. Luchuan (LC) pigs are a Chinese breed renowned for their distinctive black and white coloring, superior meat quality and rapid reproduction, but their growth rate is slow. Over the course of approximately two decades of controlled breeding, the LC pigs maintained at the Shanghai Academy of Agricultural Sciences (Shanghai, China) have diverged into two phenotypes: one characterized by obesity (FLC) and the other by leanness (LLC). Recent studies indicate a correlation between microorganisms and the differentiation of host phenotypes. In this study, we examined the fecal microbiota profiles and serum metabolites of FLC and LLC pigs. The body weight, chest circumference, and alanine aminotransferase and aspartate aminotransferase enzyme activities were increased in the FLC pigs compared to the LLC pigs. Conversely, the levels of the Fusobacterium and Streptococcus genera were lower in the FLC pigs, while the number of Firmicutes, Lactobacillus, Phascolartobacterium, and Rikenellaceae_RC9_gut_group members were higher. A total of 52 metabolites were altered between the two groups, with many playing crucial roles in prolactin signaling, oocyte meiosis, and aldosterone-regulated sodium reabsorption pathways. The correlation analyses demonstrated a significant association between the modified microbiota and metabolites and the phenotypic variations observed in the LC pigs. Specifically, Jeotgalicoccus was positively correlated with the body weight and chest circumference, but was negatively correlated with metabolites such as 2-mercaptobenzothiazole and N1-pyrazin-2-yl-4-chlorobenzamide, which were positively associated with Bacteroides. These results provide compelling evidence for a novel relationship between the gut microbiome and metabolome in the phenotypic differentiation of LC pigs. [ABSTRACT FROM AUTHOR]

Simple Summary: Simple Summary: Currently, research on livestock production suffers from isolation from other disciplines and a generalist nature, which makes publishing in top-tier journals a very difficult task. This situation is even more drastic when it comes to turkey meat research, which is an underdeveloped area that has historically suffered from a lack of resources compared to other species. For this reason, the aim of the present study is to develop a tool that allows researchers to determine which carcass and meat quality traits are related to increased interest by the scientific community and the quality standards of the journals in which studies are published. Variables improving journal standards include carcass dressing traits, muscle fibers properties, pH, colorimetry, some texture and water captivity traits, and chemical composition. Contrarily, carcass or piece yield is not a recommended variable to be performed in studies, as this parameter did not show a clear impact on publication quality. Finally, measures after 72 h are contraindicated since they showed a correlation with poor journal quality standards. Thus, this work can be used as a guideline for designing turkey carcass and meat quality studies, describing parameters to prioritize in order to maximize the impact quality of publication in the scientific community. The present research aims to describe how turkey meat and carcass quality traits define the interest of the scientific community through the quality standards of journals in which studies are published. To this end, an analysis of 92 research documents addressing the study of turkey carcass and meat quality over the last 57 years was performed. Meat and carcass quality attributes were dependent variables and included traits related to carcass dressing, muscle fiber, pH, colorimetry, water-holding capacity, texture, and chemical composition. The independent variables comprised publication quality traits, including journal indexation, database, journal impact factor (JIF), quartile, publication area, and JIF percentage. For each dependent variable, a data-mining chi-squared automatic interaction detection (CHAID) decision tree was developed. Carcass or piece yield was the only variable that did not show an impact on the publication quality. Moreover, color and pH measurements taken at 72 h postmortem showed a negative impact on publication interest. On the other hand, variables including water-retaining attributes, colorimetry, pH, chemical composition, and shear force traits stood out among the quality-enhancing variables due to their low inclusion in papers, while high standards improved power. [ABSTRACT FROM AUTHOR]

Simple Summary: The application of advantages can not only effectively improve the disease resistance and meat quality of livestock, but also significantly promote the reproduction and growth of livestock and poultry. A total of 78,579 SNPs and 42,018 ROHs were detected from autosomal samples of 380 meat rabbits after quality control for whole-gene association analysis using a mixed linear model. The homozygosity of the population genome was evaluated, and the number, length, frequency, and distribution of ROHs in the population were analyzed. Notably, candidate genes associated with growth and development were found in the high-frequency ROH region. In this study, the identified candidate genes can be used as molecular markers for assisted selection in meat rabbits. At the same time, the inbreeding situation based on ROH evaluation can provide reference for breeding and breeding preservation of meat rabbits. The application of heterosis can not only effectively improve the disease resistance and meat quality of livestock, but also significantly enhance the reproduction and growth of livestock and poultry. We conducted genome-wide association studies using data from F2 crossbred meat rabbits to screen out candidate genes with significant dominant effects associated with economic trait variation. High-throughput sequencing technology was used to obtain SNPs covering the whole genome to evaluate the homozygosity of the population genome, and analyze the number, length, frequency, and distribution of ROHs in the population. Candidate genes related to economic traits of meat rabbits were searched based on high-frequency ROH regions. After quality control filtering of genotype data, 380 F2 crossbred rabbits were identified with 78,579 SNPs and 42,018 ROHs on the autosomes. The fitting of the Logistic growth curve model showed that 49-day-old rabbits were a growth inflection point. Then, through genome-wide association studies, 10 SNP loci and seven growth trait candidate genes were found to be significantly related to body weight in meat rabbits at 84 days of age. In addition, we revealed the functional roles and locations of 20 candidate genes in the high-frequency ROH region associated with economic traits in meat rabbits. This study identified potential genes associated with growth and development in the high-frequency ROH region of meat rabbits. In this study, the identified candidate genes can be used as molecular markers for assisted selection in meat rabbits. At the same time, the inbreeding situation based on ROH assessment can provide reference for breeding and breeding preservation of meat rabbits. [ABSTRACT FROM AUTHOR]

Simple Summary: In meat production, the fat within an animal's muscles, known as intramuscular fat (IMF), is key to quality. This study investigated how breeding rabbits for higher or lower IMF levels affect their gut microorganisms. We focused on a rabbit population that was bred over 10 generations to achieve either high-IMF or low-IMF levels. Our findings show that genetic selection changes the gut's microbial composition, with more noticeable differences at the genus level than at the broader phylum level. High-IMF rabbits had different abundances of Escherichia, Methanobrevibacter, and Hungateiclostridium microorganisms compared to low-IMF rabbits, amongst others. We identified four specific microorganisms that could predict a rabbit's IMF genetic line with 78% accuracy. This research highlights the link between muscle fat genetics and gut microorganisms, opening the possibility of developing microbiome modulation strategies to influence IMF in animals, which could improve meat quality. Intramuscular fat (IMF) content is important for meat production and human health, where the host genetics and its microbiome greatly contribute to its variation. The aim of this study is to describe the consequences of the genetic modification of IMF by selecting the taxonomic composition of the microbiome, using rabbits from the 10th generation of a divergent selection experiment for IMF (high (H) and low (L) lines differ by 3.8 standard deviations). The selection altered the composition of the gut microbiota. Correlated responses were better distinguished at the genus level (51 genera) than at the phylum level (10 phyla). The H-line was enriched in Hungateiclostridium, Limosilactobacillus, Legionella, Lysinibacillus, Phorphyromonas, Methanosphaera, Desulfovibrio, and Akkermansia, while the L-line was enriched in Escherichia, Methanobrevibacter, Fonticella, Candidatus Amulumruptor, Methanobrevibacter, Exiguobacterium, Flintibacter, and Coprococcus, among other genera with smaller line differences. A microbial biomarker generated from the abundance of four of these genera classified the lines with 78% accuracy in a logit regression. Our results demonstrate different gut microbiome compositions in hosts with divergent IMF genotypes. Furthermore, we provide a microbial biomarker to be used as an indicator of hosts genetically predisposed to accumulate muscle lipids, which opens up the opportunity for research to develop probiotics or microbiome-based breeding strategies targeting IMF. [ABSTRACT FROM AUTHOR]

Simple Summary: Nutritional factors are crucial to performance and meat quality. We investigated the effects of dietary CP and lysine levels on growth performance, slaughter performance, meat quality, and myofiber characteristics in slow-growing chicken and found that 18.0% CP increased BWG and shear force and had the lowest myofiber density and the largest myofiber diameter. Dietary lysine level affected myofiber diameter. Reducing dietary CP level and adding appropriate lysine can reduce myofiber diameter and increase perimysium thickness and endomysium thickness, therefore reducing shear force and improving meat tenderness. This study aimed to investigate the effects of dietary crude protein (CP) and lysine levels on growth performance, slaughter performance, meat quality, and myofiber characteristics of slow-growing chicken. A 3 × 3 factorial experiment was arranged, and the chickens were fed with 3 levels of dietary CP (16.0%, 17.0%, 18.0%) and 3 levels of dietary lysine (0.69%, 0.84%, 0.99%). A total of 540 8-week-old Beijing-You Chicken (BYC) female growing chickens were randomly allocated to 9 groups, 5 replicates per group, and 12 chickens per replicate. The birds were randomly allocated to one of the 9 experimental diets. Growth performance, slaughter performance, meat quality, and myofiber characteristics were determined at 16 weeks of age. The results showed that dietary CP level and the interaction of dietary CP and lysine levels affected average feed intake (AFI) (p < 0.05). The AFI in the 16.0% CP and 17.0% CP groups was higher than in the 18.0% CP group (p < 0.05). Dietary CP levels significantly affected body weight gain (BWG) (p < 0.05) at 9 to 16 weeks. The 18.0% CP group had the highest BWG (93.99 g). Dietary CP levels affected the percentage of leg muscle yield, and the percentage of leg muscle yield of the 16.0% CP group was significantly lower than that in the other two groups (p < 0.05). Dietary CP and lysine levels alone and their interactions did not affect pH24h, drip loss, and cooking loss of breast muscle (p > 0.05). The shear force of the 18.0% CP group (29.55 N) was higher than that in the other two groups (p < 0.01). Dietary CP level affected myofiber characteristic (p < 0.01), with the lowest myofiber density (846.35 p·mm−2) and the largest myofiber diameter (30.92 μm) at 18.0% CP level. Dietary lysine level affected myofiber diameter, endomysium thickness, perimysium thickness (p < 0.01), with the largest myofiber diameter (29.29 μm) obtained at 0.84% lysine level, the largest endomysium thickness (4.58 μm) at 0.69% lysine level, and the largest perimysium thickness (9.26 μm) at 0.99% lysine level. Myofiber density was negatively correlated with myofiber diameter and endomysium thickness (R = −0.883, R = −0.523, p < 0.01); perimysium thickness had a significant negative correlation with shear force (R = −0.682, p < 0.05). Therefore, reducing dietary CP level and adding appropriate lysine can reduce myofiber diameter and increase perimysium thickness, reducing shear force and improving meat tenderness. A high lysine level (0.99%) in the low-CP (16.0%) diet can improve meat tenderness by regulating the myofiber characteristic without affecting production performance. [ABSTRACT FROM AUTHOR]

Simple Summary: Soybean meal is the main constituent of poultry feed, and the global supply of soybeans has decreased because of an imbalance between its demand and supply, primarily caused by the growing world population and reduced cultivation area. Therefore, a cheap and environmentally sustainable alternative protein source is urgently needed to maintain the sustainability of poultry production. In this study, we demonstrated that substituting 12% of soybean meal with either fall armyworm larvae or black soldier fly larvae enhances the growth, blood haematology, gut morphometry, and meat quality of broiler chickens. Consequently, soybean meal can be substituted with protein-rich insects in the poultry feed. The primary challenge facing the global animal industry is the scarcity of protein feed resources. Various insects are gaining prominence as innovative feed sources due to their economic, environmentally friendly, and nutritious attributes. The purpose of the present study was to determine the effects of a partial replacement of soybean meal with fall armyworm Spodoptera frugiperda (Lepidoptera: Noctuidae) and black soldier fly Hermetia illucens (Diptera: Stratiomyidae) on the growth performances, blood parameters, gut histology, and meat quality of broilers. A total of 350 1-day-old (40 ± 0.15 g) male chicks (Ross 308) were randomly assigned to seven experimental meals. Each treatment was repeated five times with 50 birds per dietary treatment. The seven dietary treatments included 4, 8, and 12% replacements of SBM with larvae of S. frugiperda and H. illucens. SBM was the basal diet considered the control. The data showed that broilers fed 12% S. frugiperda or H. illucens exhibited a significantly higher (p < 0.05) live weight, average daily weight gain, and improved the feed conversion ratio. Meals with 12% S. frugiperda or H. illucens significantly enhanced (p < 0.05) haematological and gut histological parameters, including villus height, crypt depth, villus width, and villus height/crypt depth ratios. The meat of broilers fed the 12% S. frugiperda diet showed significantly higher (p < 0.05) lightness and yellowness. Replacing soybean meal up to 12% with either S. frugiperda or H. illucens larvae improves the growth performance, blood haematology, gut morphometry, and meat quality traits of broilers. [ABSTRACT FROM AUTHOR]

Simple Summary: Nuclear Receptor Subfamily 4 Group A Member 1 (NR4A1) acts as a transcription factor to participate in lots of physiological activities including cell proliferation and cell differentiation. In this study, we found that NR4A1 promoted goat intramuscular preadipocyte differentiation through the PI3K/AKT pathway. This study provides important information about NR4A1 in the intramuscular preadipocyte differentiation in goats and therefore identifies a target for goat meat quality improvement studies. As a transcription factor, Nuclear Receptor Subfamily 4 Group A Member 1 (NR4A1) binds to downstream target genes to participate in cell proliferation and cell differentiation. We found that the NR4A1 reached the highest expression at 60 h after the differentiation of goat intramuscular preadipocytes. Overexpression of goat NR4A1 increased the number of intracellular lipid droplets and up-regulated the expression of adipocyte-differentiation-related marker genes including AP2, SREBP1, ACC, GPAM, and DGAT2, while the relative expression levels of Pref-1 and HSL were significantly decreased. On the contrary, after NR4A1 was knocked down by siRNA, the number of intracellular lipid droplets and the relative expression levels of LPL, CEBPα, CEBPβ, ACC, and DGAT2 were significantly decreased, and the relative expression levels of Pref-1 and HSL were significantly up-regulated. These results suggest that NR4A1 promotes the differentiation of goat intramuscular preadipocytes. Transcriptome sequencing was carried out after overexpression of goat NR4A1, and the KEGG enrichment analysis result showed that the most differentially expressed genes were related to adipocyte differentiation and were enriched in the PI3K-Akt signaling pathway. LY249002, an inhibitor of the PI3K-Akt signaling pathway, was introduced and decreased the number of intracellular lipid droplets, and the relative expression levels of C/EBPα, SREBP1, AP2, C/EBPβ, GPAM, ACC, DGAT1, DGAT2, and ATGL were decreased accordingly. The above results indicate that overexpression of goat NR4A1 may promote the differentiation of intramuscular preadipocytes through the PI3K-Akt signaling pathway. [ABSTRACT FROM AUTHOR]

Simple Summary: The Lueyang black-bone chicken is a vital poultry resource originating from China. This study aimed to investigate the effects of different rearing systems on the meat quality of Lueyang black-bone chickens via untargeted metabolomics. Compared with caged rearing, cage-free rearing significantly reduced chicken carcass yield and increased the shear force of leg muscles. In addition, the cage-free rearing mode promoted the accumulation of nutrients, such as phospholipids, unsaturated fatty acids, glutamate, and adenosin 3′-monophosphate. Moreover, the cage-free rearing system also enhanced the accumulation of volatile organic compounds, such as aldehydes, alcohols, and ketones, which greatly contribute to the meat flavor. In summary, this study provides a theoretical basis for cage-free rearing as a better rearing mode for Lueyang black-bone chickens. The Lueyang black-bone chicken is a specific native chicken strain in China. This study aimed to investigate the effects of different rearing systems on the meat quality of Lueyang black-bone chickens. Six hundred Lueyang black-bone hens were randomly divided into two groups at 7 weeks of age and raised in cage and cage-free systems for 20 weeks. The carcass yield, meat quality, and total metabolites were measured in both the leg and breast muscles. By comparison, the carcass yield of hens in the cage-free (CF) group (1.26 ± 0.09 kg) was significantly lower than that in the caged rearing (CR) group (1.52 ± 0.15 kg). However, the shear force of leg muscles in the CF group (27.98 ± 2.43 N) was significantly greater than that in the CR group (24.15 ± 1.93 N). In addition, six samples from each group were randomly selected and their metabolites were detected by the non-targeted metabolomics technique. Among these metabolites, 408 and 354 significantly differentially abundant metabolites were identified in breast and leg muscles, which were mainly involved in glycerophospholipid metabolism, unsaturated fatty acid biosynthesis, arginine and proline metabolism, and nucleotide metabolism. We found that the levels of 19 phospholipids, mainly phosphatidylcholines and lysophosphatidylcholines, were significantly greater in the CF group than in the CR group. Additionally, the contents of eight unsaturated fatty acids, linoleic acid, and linolenic acid were dramatically greater in the CF group than in the caged group. The accumulation of 4-hydroxy-proline, glutamate, and adenosine 3′-monophosphate (AMP) was enhanced in the CF group. Moreover, many more volatile organic compounds were identified in the muscles of the cage-free group, enhancing the flavor of the chicken meat. In conclusion, the cage-free rearing mode facilitates the accumulation of nutrients and flavor substances in the chicken meat and is a better rearing system for Lueyang black-bone chickens. [ABSTRACT FROM AUTHOR]

Simple Summary: Positive and negative pressure ventilation systems are widely used in poultry farming to control the internal environment of poultry houses, especially in tropical regions, in which hot and humid climates can pose challenges to the thermal regulation of animals. Knowing that thermal stress impacts the quality of animal meat, this study aimed to evaluate the thermal performance and quality of poultry meat in these two types of shed. The main results found here were that the negative pressure system presents lower temperatures and air enthalpy, and the animals reared in this system have better quality meat. We recommend the negative ventilation system for broiler producers in tropical regions due to its ability to provide better thermal indicators and chicken meat quality. This study aimed to evaluate the thermal performance and meat quality in broilers reared in positive pressure tunnel ventilation (PP) and negative pressure tunnel ventilation (NP) in production houses. 320 Cobb broilers (40 broilers per house) were used. Pectoralis major muscles from 40 broilers (10 broilers per house) were randomly selected and analysed for L* (lightness), a* (redness), b* (yellowness), pH, drip loss (DL), cooking loss (CL) and shear force (SF). Air temperature and humidity of the transportation and slaughterhouse waiting room were recorded in the last week of rearing. Subsequently, the enthalpy comfort index (ECI) was calculated. Air temperature and ECI were higher (p < 0.05) in positive pressure sheds, whereas relative humidity was higher (p < 0.001) in negative pressure sheds. There was no statistically significant difference between the enthalpy comfort index during transport and lairage (p > 0.005). Meat quality defects (high L*, DL, CL, SF) were found in PP and NP. It was observed that b* was higher in PP, although pH and CL were higher in NP. Differences in pH, b* and CL indicate that broilers from PP had a higher level of heat stress. In conclusion, differences in pH, b*value and cooking loss in breast broilers indicate that birds in PP had a higher level of heat stress. Additional studies investigating pre-slaughter handling methods to minimise injuries and heat stress are recommended in order to improve animal welfare and meat quality. [ABSTRACT FROM AUTHOR]

Simple Summary: Light is a very important parameter in poultry farming. It can influence production, meat quality and welfare. The increasingly popular energy-efficient light-emitting diode (LED) lighting has replaced other light sources in many farms. We aimed to investigate the effects of incandescent light (IL) and LED lighting on production, meat quality parameters and behavior. In the first five weeks, there was a significant difference in body weights between the groups. The feed conversion ratio was more favorable in all weeks in the LED group. Among the meat quality parameters, only the shear force values differed significantly between the groups. Broilers raised under LED lighting were more active, spent more time socializing and rested less. The results indicated that LED lighting positively impacts animal welfare and production efficiency. Many farms have been replacing traditional lighting sources with light-emitting diode (LED) bulbs because of technological modernization. We aimed to investigate the effects of incandescent lighting (IL) and LED lighting on Cobb 500 broiler chickens for six weeks. Production parameters (body weight, feed consumption, feed conversion ratio), calculated slaughter values (yield%, relative breast%, thigh%) and breast meat quality parameters (pH at 45 min and 24 h postmortem, color, drip loss, kitchen equipment losses, shear force, meat composition) were recorded. Non-stop recordings were used to analyze the behavior of the birds during several periods of rearing. The LED group was significantly better in the body weight parameter between week 1 and 5 and the feed conversion ratio between week 2 and 3. The most significant difference in behavior was observed in the middle of the rearing period. The chickens in the LED group spent more time eating, drinking and interacting, and rested less. There was no difference in the meat quality parameters; only shear force was significantly lower in the LED group (1781.9 g/s vs. 2098.8 g/s). According to our results, LED lighting can bring about positive changes in animal production efficiency, behavior and other important characteristics for meat consumers. [ABSTRACT FROM AUTHOR]

Simple Summary: The molecular mechanism underlying muscle development in goats is complex, and the key genes commanding the growth performance and meat quality of different breeds remain unclear. Herein, we present temporal transcriptome research on Longissimus dorsi (LD) muscle of two goat breeds from embryo to 12 months old, with extreme phenotypic differences in production and meat quality traits, using an Illumina system for the identification of key genes to improve production efficiency in goats. In this study, we measured the growth performance and intramuscular fat (IMF) content of the Longissimus dorsi (LD) of Fuqing goats (FQs) and Nubian goats (NBYs), which exhibit extreme phenotypic differences in terms of their production and meat quality traits. RNA-Seq analysis was performed, and transcriptome data were obtained from the LD tissue of 3-month fetuses (E3), 0-month lambs (0M), 3-month lambs (3M), and 12-month lambs (12M) to reveal the differences in the molecular mechanisms regulating the muscle development and IMF deposition between FQs and NBYs. The results showed that a higher body weight and average daily gain were observed in the NBYs at three developmental stages after birth, whereas a higher IMF content was registered in the FQs at 12M. Additionally, transcriptome profiles during the embryonic period and after birth were completely different for both FQs and NBYs. Moreover, DEGs (KIF23, CCDC69, CCNA2, MKI67, KIF11, RACGAP1, NUSAP1, SKP2, ZBTB18, NES, LOC102180034, CAPN6, TUBA1A, LOC102178700, and PEG10) significantly enriched in the cell cycle (ko04110) at E3 (FQs vs. NBYs), and DEGs (MRPS7, RPS8, RPL6, RPL4, RPS11, RPS10, RPL5, RPS6, RPL8, RPS13, RPS24, RPS15, RPL23) significantly enriched in ribosomes (ko03010) at 0M (FQs vs. NBYs) related to myogenic differentiation and fusion were identified. Meanwhile, the differences in glucose and lipid metabolism began at the E3 timepoint and continued to strengthen as growth proceeded in FQs vs. NBYs. DEGs (CD36, ADIROQR2, ACACA, ACACB, CPT1A, IGF1R, IRS2, LDH-A, PKM, HK2, PFKP, PCK1, GPI, FASN, FADS1, ELOVL6, HADHB, ACOK1, ACAA2, and ACSL4) at 3M (FQs vs. NBYs) and 12M (FQs vs. NBYs) significantly enriched in the AMPK signaling pathway (ko04152), insulin resistance (ko04931), the insulin signaling pathway (ko04910), fatty acid metabolism (ko01212), and glycolysis/gluconeogenesis (ko00010) related to IMF deposition were identified. Further, the results from this study provide the basis for future studies on the mechanisms regulating muscle development and IMF deposition in different breeds of goats, and the candidate genes identified could be used in the selection process. [ABSTRACT FROM AUTHOR]

Simple Summary: This study aimed to reveal the single nucleotide polymorphisms (SNPs) of the bovine Stearoyl-CoA desaturase-1 (SCD1) to explore the correlation between genotypes and carcass, meat quality, adipogenic traits, fatty acid composition, and milk production traits in cattle. Four SNPs, g.21272246 A>G, g.21272306 T>C, g.21272422 C>T, and g.21272529 A>G, were found by Sanger sequencing; further statistical analysis showed that these four SNPs of the SCD1 gene were significantly associated with carcass traits and meat quality, including carcass weight, carcass fat coverage rate, rib eye area, marbling score, adipogenic traits, and fatty acid composition. Additionally, a modest effect on milk production traits, such as average milk yield and milk fat content, was observed in cows. Further haplotype analysis indicated that the combinations of H2H3 and H2H2 of SNPs had a higher value than others. Our results indicate that these four SNPs are potentially effective markers and could be used in marker-assisted breeding to improve meat and milk quality simultaneously in the future. Stearoyl-CoA desaturase-1 (SCD1) is a key enzyme in the biosynthesis of monounsaturated fatty acids and is considered a candidate gene for improving milk and meat quality traits. Sanger sequencing was employed to investigate the genetic polymorphism of the fifth exon and intron of bovine SCD1, revealing four SNPs, g.21272246 A>G, g.21272306 T>C, g.21272422 C>T, and g.21272529 A>G. Further variance analysis and multiple comparisons were conducted to examine the relationship between variation sites and economic traits in Chinese Simmental cattle, as well as milk production traits in Holstein cows. The findings revealed these four loci exhibited significant associations with carcass traits (carcass weight, carcass length, backfat thickness, and waist meat thickness), meat quality (pH value, rib eye area, and marbling score), adipogenic traits (fat score and carcass fat coverage rate), and fatty acid composition (linoleic acid and α-linolenic acid). Furthermore, these loci were additionally found to be significantly associated with average milk yield and milk fat content in cows. In addition, a haplotype analysis of combinations of SNPs showed that H2H3 has a significant association with adipogenic traits and H2H2 was associated with higher levels of linoleic acid and α-linolenic acid than the other combinations. These results suggest that the four SNPs are expected to be prospective genetic markers for the above economic traits. In addition, the function of SNPs in exon 5 of SCD1 on gene expression and protein structure needs to be explored in the future. [ABSTRACT FROM AUTHOR]

Simple Summary: The aim of this study was to explore the genetic resources of the Huitang duck (HT) in Hunan Province, China, and investigate its population structure and genetic potential through comparative analysis with various duck populations. The results showed that HT belonged to the versatile duck breed, exhibiting significant phenotypic and genetic differences compared to other duck breeds in Hunan Province. The inspection of genomic selective signals in their genome showed that selected candidate genes were involved in the growth and development of skeletal muscle and ovary. These findings provide valuable information for future breeding programs and genetic preservation of HT. The Huitang duck (HT), a long-domesticated elite local breed from Hunan Province, China, with excellent meat quality, has not had its population genetic structure and genomic selective sweeps extensively studied to date. This study measured the phenotypic characteristics of HT and conducted comparative analysis between HT and 16 different duck breeds, including wild, indigenous, and meat breeds, to characterize its population structure and genetic potential. The results revealed that HT is a dual-purpose indigenous breed with a genetic background closely related to the Youxian sheldrake and Linwu ducks. In the selective sweep analysis between HT and Linwu ducks, genes such as PLCG2, FN1, and IGF2BP2, which are associated with muscle growth and development, were identified near the 27 selection signals. The comparison between HT and Jinding ducks revealed 68 selective signals that contained important genes associated with ovarian development (GRIK4, MAP3K8, and TGIF1) and egg-laying behaviors (ERBB4). Selective sweep analysis between HT and Youxian sheldrake ducks found 93 selective regions covering genes related to both meat (IGF1R and IGFBP5) and egg-production (FOXO3 and ITPR1) traits. Our study may provide novel knowledge for exploring the population structure and genetic potential of HT, offering a theoretical basis for its breeding strategies in the future. [ABSTRACT FROM AUTHOR]

Simple Summary: Dietary supplements can affect animal growth, product quality, and various physiological factors. This study investigated the effects of supplementing hemp-derived cannabidiol (CBD) oil in the diet of goats. CBD, when included at higher levels (0.2–0.3 mL), led to improved meat quality but also altered volatile compound profiles. Additionally, CBD supplementation affected some blood variables related to immunity, metabolism, and homeostasis. Stress experienced by animals during pre-mortem management handling significantly affects both their welfare and the quality of the meat produced. Using hemp-derived CBD may offer several benefits in alleviating this issue. In this study, we investigated the effects of hemp-derived CBD supplementation on blood variables, growth performance, carcass characteristics, and meat quality in goats. Sixteen crossbred Boer goats were divided into four groups receiving a basal diet supplemented with 0 (control), 0.1, 0.2, or 0.3 mL CBD/30 kg body weight over 90 days. Although growth, carcass characteristics, and pH remained unaffected, CBD supplementation influenced several blood variables. Specifically, dietary CBD at 0.1–0.3 mL increased white blood cell (WBC) counts, while 0.3 mL CBD increased serum total protein, globulin, sodium, and carbon dioxide levels, potentially affecting protein metabolism and electrolyte balance. Over time, significant changes were noted in hematological profiles, kidney markers, protein profiles, and some electrolytes, indicating physiological adaptations. Regarding meat quality, supplementation with 0.2–0.3 mL of CBD linearly improved color redness and stability; moreover, CBD supplementation improved tenderness and textural properties, resulting in a softer meat texture. However, analysis using an E-nose indicated increased ammonia and organic solvent vapors in meat from the higher CBD groups. This study concluded that CBD supplementation up to 0.3 mL of CBD/30 kg body weight beneficially modulated blood biomarkers, meat color, and tenderness without adverse impacts on growth or carcass characteristics in goats. [ABSTRACT FROM AUTHOR]

Simple Summary: Salmonellosis affects the poultry industry globally and is a major cause of bacterial food poisoning in humans. A Salmonella infection in broiler chickens can result in lower growth rates, decreased feed efficiency and higher mortality rates. The inclusion of probiotics in chicken diets enhances their intestinal microbiota and enhances different patterns of cytokine production in response to Salmonella infection. The increasing demand from consumers for chicken products devoid of antibiotics has increased the need to identify alternatives to antibiotics for the management of Salmonella infection, colonization, and carcass contamination in poultry. Through the process of competitive exclusion, probiotics have been shown to inhibit the colonization of the gut by harmful bacteria such as Salmonella and Clostridium perfringens. Probiotic supplementation also regulates the gut flora to protect the host from infections as well as to create bacteriocins, which directly prevent the growth of pathogens. This study was therefore carried out to ascertain whether the supplementation of Pediococcus pentosaceus GT001 can influence the growth performance, meat quality, intestinal development and cecum microbiota of Salmonella typhimurium-challenged broiler chickens. This study evaluated the effects of Pediococcus pentosaceus GT001 on Salmonella typhimurium (S. typhimurium)-challenged broiler chickens. Two hundred Ross 708 broiler day-old chicks with comparable weight were distributed at random into four treatments with five replicates and ten chicks per replicate. The following were the treatment groups: (B) basal diet (control); (B + S) basal diet and birds were challenged with S. typhimurium at 1.0 × 107 cfu/g; (B + P) basal diet + Pediococcus pentosaceus GT001 at 4.0 × 108 cfu/g; (B + P + S) basal diet + P. pentosaceus GT001 at 4.0 × 108 cfu/g and birds were challenged with S. typhimurium at 1.0 × 107 cfu/g. There was a significant reduction (p < 0.05) in the body weight of the Salmonella-infected birds compared to the other treatment groups. However, the FCRs of the broilers were comparable among the different treatment groups (p > 0.05). The lipid profile and liver function indices measured were significantly enhanced in the P. pentosaceus GT001-supplemented groups (B + P and B + P + S) compared to the group that was Salmonella-challenged (p < 0.05) but were similar to those in the control group. The serum antioxidant activities, such as the T-AOC, SOD, CAT, GHS-Px and MDA, were significantly improved in the P. pentosaceus GT001-supplemented groups (B + P and B + P + S) (p < 0.05). The MDA was similar in the B + P and B + P + S groups, but both were significantly lower than the control and the Salmonella groups. The administration of P. pentosaceus GT001 enhanced the lipase and amylase levels in both the serum and intestine of the broilers (p < 0.05). The immunoglobin (IgA, IgG, IgM) and cytokine (IL-10 and IL-6) levels in the serum were significantly higher in the B, B + P and B + P + S treatment groups (p < 0.05). The immune-related organs (bursa and spleen) were significantly influenced in the birds fed with P. pentosaceus GT001. No significant variation was noted among all the dietary treatments in terms of the measured meat quality indices. The small intestinal digesta content of the Salmonella load was below a detectable range after 14 days of infection (p < 0.05). No significant differences were observed among the different treatment groups in terms of the breast pH, drip loss and meat color (p > 0.05). The inclusion of P. pentosaceus GT001 also modified the community structure in the cecum. This indicates that it has health benefits and could be incorporated in the broiler diet. [ABSTRACT FROM AUTHOR]

Simple Summary: Simple Summary: Supplementation with rumen-protected choline (RPC) can reduce dietary metabolizable energy (ME) while maintaining optimum performance, thus contributing to reducing production costs by saving grain which is the primary source of energy in the diet. Previous papers have reported on the interaction effects of ME level and RPC supplementation on production outcomes in dairy cattle and growing goats. The objective of this study was to examine the effects of ME level and RPC supplementation on the growth performance, carcass characteristics, meat quality, serum energy, lipid, and protein profiles of Karayaka lambs. In conclusion, the supplementation of RPC at 0 and 5 g/kg did not affect lamb growth performance and carcass characteristics. Given the lack of significant improvements in performance metrics, RPC supplementation would not result in net cost savings. However, it may play a role in modulating nitrogen metabolism under different dietary energy conditions, as indicated by the significant reduction in serum urea-N levels. The results of the current study indicate that there is no benefit to be gained from the supplementation of RPC in the low-energy diet of fattening lambs. This study aimed to examine the effects of metabolizable energy (ME) level and rumen-protected choline (RPC) supplementation on the growth performance, carcass characteristics, meat quality, serum energy, lipid, and protein profiles of Karayaka lambs. Twenty-eight Karayaka lambs, with an initial body weight (BW) of 26.85 ± 0.26 kg, were randomly assigned (2 × 2 factorial design) to one of four dietary treatments with two levels of ME (optimum: 2750 or low: 2500 kcal ME/kg dry matter) and two levels of RPC (0 or 4 g/d/lamb). Lambs of each group were housed in individual pens. The experiment lasted 66 d, with the first 10 d consisting of acclimation and the next 56 d of the formal experimental period. The data on BW, dietary matter intake (DMI), and serum glucose concentrations confirm that our model successfully induced low energy using 250 kcal/kg less energy than the optimum level. RPC supplementation did not significantly affect average daily DMI, total average daily gain (ADG), or feed conversion ratio (FCR) at any energy level. Additionally, there was no substantial effect on carcass characteristics, meat quality, serum lipids, energy metabolism indicators, and liver function parameters. There was also no interaction effect of RPC × ME on the parameters tested. However, at 56 d into the experiment, the interaction effect of RPC × ME on serum urea-N was highly significant, and RPC supplementation led to lower serum urea-N levels (p = 0.001). These results suggest that while RPC supplementation did not enhance overall performance and carcass characteristics in Karayaka lambs, it may play a role in modulating nitrogen metabolism, as indicated by the significant reduction in serum urea-N levels. [ABSTRACT FROM AUTHOR]

Simple Summary: This meta-analysis examines the impact of neutering on sheep production and quality, focusing on performance, carcass characteristics, and meat quality. It is observed that castrated sheep (wethers) exhibit enhanced daily weight gain and meat tenderness compared to intact rams. Furthermore, wethers display characteristics of a slenderer carcass with potentially elevated muscle content. By utilizing gene expression analysis, the research sheds light on genes associated with metabolic pathways and fat metabolism, indicating their involvement in fat formation. These results advocate for the practice of castration in sheep farming to enhance growth and meat quality. Additionally, the identified alterations in gene expression offer valuable insights for further exploration of castration's influence on muscle development in sheep. Objective: The study aimed to investigate the effects of castration on performance, carcass characteristics, and meat quality in sheep, as well as explore the expression of key genes related to metabolic pathways and muscle growth following castration. Methods: A meta-analysis approach was utilized to analyze data from multiple studies to compare the performance, carcass characteristics, and meat quality of castrated sheep (wethers) with intact rams. Additionally, protein–protein interaction (PPI) networks, differential gene expression (DEG) interactions, Gene Ontology (GO) terms, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were examined to identify molecular mechanisms associated with fat metabolism and muscle development in sheep tails. Results: The analysis revealed that castrated sheep (wethers) exhibited improved average daily gain, increased tenderness, lower backfat thickness, and a tendency for greater loin muscle area compared to intact rams. This suggests that castration promotes faster growth and results in leaner carcasses with potentially higher muscle content. Furthermore, the identification of downregulated DEGs like ACLY, SLC27A2, and COL1A1 and upregulated DEGs such as HOXA9, PGM2L1, and ABAT provides insights into the molecular mechanisms underlying fat deposition and muscle development in sheep. Conclusions: The findings support the practice of castration in sheep production as it enhances growth performance, leads to leaner carcasses with higher muscle content, and improves meat tenderness. The identified changes in gene expression offer valuable insights for further research into understanding the impact of castration on muscle development and fat metabolism in sheep. This meta-analysis contributes to the knowledge of molecular mechanisms involved in fat deposition in sheep, opening avenues for future investigations in livestock fat metabolism research. [ABSTRACT FROM AUTHOR]

Simple Summary: In this study, we compared two different methods of raising broiler chickens: modern colony cages and traditional floor systems. We aimed to understand how each system impacts both the production and wellbeing of the chickens. We discovered that, while colony cages excel in maintaining optimal environmental conditions and promoting rapid growth, they also create challenges, such as leg deformities and difficulty standing. Conversely, traditional floor systems present issues such as heat stress, affecting broiler growth. Our findings emphasize the need to achieve a balance between chicken welfare and production objectives in poultry farming. By recognizing these differences, we can strive to enhance broiler rearing practices, ensuring the birds' wellbeing while still meeting the consumer demand for poultry products. This study compares the effects of modern colony cage systems and traditional floor systems on the production and welfare of broiler chickens. Through two trials spanning 35 days each, we evaluated various physiological parameters, including growth performance, bone health, stress responses, and meat quality. Colony cages demonstrated superior thermal regulation and growth performance compared to traditional floor systems, but also exhibited higher frequencies of leg deformity and reduced standing ability. Conversely, the broilers in traditional floor systems experienced heat stress-related challenges, impacting the meat quality. Our findings underscore the need to balance productivity with animal welfare in broiler farming practices. By understanding the distinct impacts of different housing systems, we can work towards improving broiler rearing methods to ensure optimal welfare and production outcomes. [ABSTRACT FROM AUTHOR]

Simple Summary: Pigs lack functional sweat glands, hence being very susceptible to heat stress. The optimum temperature in which pigs would thrive is around 20 °C, depending on age and weight. Pigs could achieve higher heat dissemination, e.g., by increasing body contact with the cooler ground and panting, but also through an undesirable reduction in feed intake. In addition, under conditions of severe heat stress, animals may become more susceptible even to immune challenges due to damage to the structure of the intestinal wall. Thus, heat stress can affect the proper functioning of metabolism, which, in addition to having implications on animal welfare, also affects the quality of meat and meat products. Cooling systems are not yet commonly seen on farms. Sprinkler systems are the most used cooling system, followed by water pads and fogging systems, for finishing pigs. As our climate continues to warm, monitoring daily feed intake and water consumption levels, along with the implementation of cooling systems, must become tools to minimize the adverse effects of hot weather. Heat stress is a significant environmental problem that has a detrimental impact on animal welfare and production efficiency in swine farms. The current study was conducted to assess the effect of low-intensity showers, provided during critical high-temperature hours daily, on body external temperature, feeding pattern, and carcass and meat quality characteristics in fattening pigs. A total of 400 animals (200 barrows and 200 gilts) were randomly allotted in 40 pens. A shower nozzle was installed over 20 pens (half barrows and half gilts) where pigs received a low-intensity shower for 2 min in 30 min intervals from 12 to 19 h (SHO group). Another group without showers was also considered (CON). Feeder occupancy measurement, thermographic measures, and carcass and meat quality parameters were studied. In the periods with higher environmental temperatures, SHO animals showed an increase in the feeder occupancy rate compared to the CON group. A decrease in temperature was observed after the shower, regardless of the anatomical location (p < 0.005). The treatment with showers led to higher values than in the CON group of 4.72%, 3.87%, 11.8%, and 15.1% for hot carcass weight, lean meat yield, and fat thickness in Longissimus Dorsi (LD) and Gluteus Medius muscles, respectively (p < 0.01). Pork from CON showed a 14.9% higher value of drip loss, and 18.9% higher malondialdehyde concentration than SHO (p < 0.01); meanwhile, intramuscular fat content was 22.8% higher in SHO than in CON (p < 0.01). On the other hand, the CON group exhibited higher L* (2.13%) and lower a* and b* values (15.8% and 8.97%) compared to the SHO group. However, the pH20h of the CON group was significantly lower than that of the SHO group (p < 0.001), indicating a softer pH decrease. Related to fatty acids in subcutaneous outer and inner layers and intramuscular fat, the CON group showed higher ΣSFA and lower ΣMUFA and Δ9-desaturase indexes than SHO (p < 0.05). In conclusion, the amelioration of heat stress through showers at critical times should be considered an interesting tool that improves both carcass and meat quality, as well as animal welfare. [ABSTRACT FROM AUTHOR]

Simple Summary: Simple Summary: Lycium barbarum (Wolfberry) extract is predominantly utilized in livestock and poultry applications. However, the impact of unprocessed branches and leaves of Lycium barbarum as a roughage source on ruminant growth performance, slaughter metrics, and rumen micro-organisms remains not well understood. This investigation examines the effects of incorporating Lycium barbarum branches and leaves into the diet of Hu sheep, specifically assessing growth performance, slaughter results, and meat quality through feeding trials and slaughter tests. Additionally, this study explored the impact on rumen microflora by utilizing 16S rDNA sequencing technology. Findings indicated that diet inclusion of Lycium barbarum branches and leaves could enhance nutrient absorption, which in turn improves growth performance and certain aspects of meat quality. The Lycium barbarum branches and leaves (LBL) are known to contain a range of active substances that have positive effects on animal immunity and antioxidation. This study aimed to examine how LBL impacts the growth and slaughter performance as well as rumen fermentation and microbiota in Hu sheep. A total of 50 male Hu sheep of indigenous origin, aged 3 months, were randomly divided into 5 groups of 10 sheep each. The groups were given different levels of LBL supplementation (0%, 3%, 6%, 9%, and 12%) to evaluate growth performance and nutrient apparent digestibility. Rumen fluid samples were collected for analysis of the fermentation parameters and rumen chyme was examined to study the rumen microbiota. The slaughter performance, meat quality, and organ index were evaluated at the conclusion of the experiment. The results showed that the final body weight and average daily gain of the LBL1 group were significantly higher than those of the CON group, LBL3 group, and LBL4 group (p < 0.05). The average dry matter intake of the LBL4 group was significantly lower than that of other experimental groups (p < 0.05). The apparent digestibility of CP in the LBL1 and LBL2 groups was higher than that in other experimental groups (p < 0.05). At the same time, the eye muscle area and grade-rule (GR) value of Hu sheep in the LBL1 group significantly increased and the quality of Hu sheep meat improved (p < 0.05). There was no significant difference in organ weight and organ index between the experimental groups (p > 0.05). The pH of the rumen fluid in the LBL1 group was significantly lower than that in the CON group (p < 0.05). There was no significant difference in the NH3-N content between the experimental groups (p > 0.05). The propionate and valerate in the rumen fluid of Hu sheep in the LBL2 group were significantly higher than those in other experimental groups (p < 0.05). In addition, this had no significant effect on the structure and abundance of the rumen microbiota (p > 0.05). LBL is a promising functional feed. Adding an appropriate amount of LBL to the diet can improve the feed efficiency, growth performance, and meat quality of Hu sheep but has no adverse effects on the rumen. In this experiment, the appropriate supplemental level of LBL in the diet was 3%. [ABSTRACT FROM AUTHOR]

Simple Summary: Various kinds of yellow-feathered chickens are crossbred from Chinese local native chicken breeds and introduced broilers. The individual parts of yellow-feathered chickens are less suitable for sale after slaughtering than those of broilers, and they have mainly been sold as live whole chickens. With the establishment of cold chain logistics for chicken in China, chilled-type and processed yellow-feathered chicken products have appeared in the market. Xueshan chicken, a yellow-feathered chicken breed, which has high meat quality and good taste, is bred to meet the diversified needs of the market by Jiangsu Lihua Breeding Company. The present study used Xueshan chicken as an experimental model to determine the effect of sex on the slaughtering performance and meat quality. This study provides valuable breeding references for poultry producers by determining the basic production phenotypes of yellow-feathered chickens. The demand for high-quality chilled chicken has continued to increase in China. Chickens are sexually dimorphic, and to better understand the specific differences in chicken production based on sex, we examined how sex affects growth performance, carcass traits, and meat quality of yellow-feathered chickens. Male and female Xueshan chickens were used as the experimental model. Although males exhibited better growth performance, including body weight (BW), body slope, keel, shank length, and shank girth (p < 0.05), as well as carcass traits, such as dressed weight, leg muscle, and lean meat, females had higher carcass and breast muscle yields (p < 0.05). Males had higher follicle density and yellowness (b*) of the skin and better skin than females (p < 0.05). Among blood biochemical parameters, the serum content of corticosterone (CORT) was higher in males, while those of superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), total antioxidant capacity (T-AOC), and catalase (CAT) were lower in males than in females (p < 0.05). The pH levels, shear force, and moisture content quality were better in male breast meat, while the intramuscular fat content (IMF) was lower in males than in females (p < 0.05). The redness (a*) and moisture content were higher in male leg meat, while the pH, water-loss rate (WLR), lightness (L*), and IMF were lower (p < 0.05). The muscle fiber diameter and cross-sectional area were also higher in males (p < 0.05). Consumers felt that soup of male chicken was better than female (p < 0.05), while mouthfeel and tenderness acceptance of breast meat were different between the sexes. These results indicate that female chickens can be marketed as a whole carcass, while males are more suitable for processed carcass products. This study provides significant insights into the production and processing methodologies of yellow-feathered chickens. [ABSTRACT FROM AUTHOR]

Simple Summary: Simple Summary: The unrestricted usage of antibiotics led to the emergence of new antibiotic-resistant strains of pathogens, making it a concern in most countries. The restriction on the use of antibiotics in poultry has led to an increase in natural products that could serve as alternative antibiotics. Mushroom use in poultry nutrition is a major stride toward finding alternatives to antibiotics. This review aims to present a comprehensive overview of the role of different species of mushrooms commonly used in poultry in the performance, immunomodulatory actions, cholesterolemic properties, and meat quality of poultry birds. The restriction on the use of antibiotics in poultry has led to an increase in the use of natural products that could serve as alternatives to antibiotics. Mushrooms contain bioactive compounds that exhibit antifungal, antiparasitic, antibacterial, antioxidant, antiviral, anti-inflammatory, and cytotoxic properties. Hence, they are being tested, revealing as performance-enhancing natural feed additives for livestock. This review focused on the role of different species of mushrooms commonly used in poultry on the performance, immunomodulatory actions, cholesterolemic properties, and meat quality of poultry birds. Different studies reviewed show that mushrooms could positively impact poultry production, improve growth performance, modulate immune response, exert tissue antioxidant activity, influence intestinal morphology, enhance gut microbiome, and improve lipid profile. The variations in their efficacy could be attributed to the variations in physicochemical properties of different species and dosage levels applied in the experiments. However, the use of mushrooms as a natural product supplement is in its infancy, and more basic, pilot and large-scale research is required to make it a viable approach for improving immune responses in the poultry industry. [ABSTRACT FROM AUTHOR]

Simple Summary: In the process of calf rearing, it is inevitable to encounter issues of illness and death among calves. Often, due to the inability to detect sicknesses such as diarrhoea in a timely fashion, these sicknesses lead to the calves' demise. This research starts from the practical application needs, and proposes the development of a monitoring system using deep learning technology to monitor the daily standing and lying behaviour of calves to predict their condition and adaptation to the environment. By analysing the standing and lying time of calves, the system can provide early warnings about calves' condition and health status. This research helps to promptly grasp calves' condition and growth status, thereby improving their welfare and management, enhancing the health condition of reared calves, ensuring the quality and safety of meat and milk, and reducing production costs. This research method also offers a new idea for the construction of smart ranches, as the construction of precision and smart ranches is not only a demand of consumers but also an inevitable direction for the development of the breeding industry. Standing and lying are the fundamental behaviours of quadrupedal animals, and the ratio of their durations is a significant indicator of calf health. In this study, we proposed a computer vision method for non-invasively monitoring of calves' behaviours. Cameras were deployed at four viewpoints to monitor six calves on six consecutive days. YOLOv8n was trained to detect standing and lying calves. Daily behavioural budget was then summarised and analysed based on automatic inference on untrained data. The results show a mean average precision of 0.995 and an average inference speed of 333 frames per second. The maximum error in the estimated daily standing and lying time for a total of 8 calf-days is less than 14 min. Calves with diarrhoea had about 2 h more daily lying time (p < 0.002), 2.65 more daily lying bouts (p < 0.049), and 4.3 min less daily lying bout duration (p = 0.5) compared to healthy calves. The proposed method can help in understanding calves' health status based on automatically measured standing and lying time, thereby improving their welfare and management on the farm. [ABSTRACT FROM AUTHOR]

Simple Summary: Zilpaterol hydrochloride (ZH) is an additive used to enhance the growth performance and dressing carcass in ruminants. However, its use can lead to a reduction in meat quality, resulting in tougher meat. Meat tenderness is a crucial quality trait that affects consumer acceptability, satisfaction, and repeat purchase. Studies have shown that supplementing ruminants with vitamin D3 (D3) before slaughter can improve meat tenderness. It is believed that supplementing cattle treated with ZH with D3 can mitigate the negative effects of ZH and improve meat quality. In this study, we aimed to evaluate the combined effect of ZH and D3 on growth performance, energy efficiency, carcass traits, and meat quality of feedlot lambs. ZH supplementation improved growth, energy efficiency, and carcass quality but resulted in tougher meat. In contrast, supplementing lambs with D3 negatively affected dry matter intake and weight gain. However, D3 improved meat pH and color attributes but had no effect on reducing toughness. In addition, lambs fed both additives (ZH and D3) as well reduced their dry matter intake and weight gain. The inclusion of vitamin D did not reduce the toughness of the meat related to the use of zilpaterol. This study evaluated the impact of supplementing ZH in combination with D3 on the growth performance, energy efficiency, carcass traits, and meat quality of feedlot lambs. Thirty-two Dorper × Katahdin cross lambs (37.3 ± 5.72 kg) were utilized in a 29 d experiment in a completely randomized block design with a 2 × 2 factorial structure consisting of two levels of ZH for 26 d (0 and 0.20 mg/kg PV−1) and two levels of D3 for 7 d (0 and 1.5 × 106 IU/d−1). ZH improved (p ≤ 0.05) the average daily gain (ADG) and feed efficiency by 9.9% and 17.8%, respectively, as well as hot carcass weight (HCW) and dressing carcass by 4.3% and 2.6%, respectively. (p ≤ 0.03). However, ZH increased (p < 0.01) muscle pH and Warner–Bratzler shear force (WBSF) (2.5 and 23.0%, respectively). D3 supplementation negatively affected (p ≤ 0.02) dry matter intake (DMI) (last 7 d) and ADG by 15.7% and 18.1%. On the other hand, D3 improved the pH of the longissimus thoracis muscle by 1.7% (p = 0.03) without affecting WBSF. When D3 was supplemented in combination with ZH, it was observed that meat quality was improved by reducing muscle pH compared to lambs treated only with ZH. However, D3 did not improve the meat tenderness negatively affected by ZH supplementation. [ABSTRACT FROM AUTHOR]

Simple Summary: Tributyrin has been used as a feed additive to modify the gastrointestinal microflora structure of ruminants, whereas its potential impact on meat quality characteristics has not been well characterized. To fully investigate its potential, an experiment was performed to evaluate the effects of supplementary tributyrin on the meat quality characteristics of foreshank muscle of weaned lambs. When tributyrin was added into the diets of weaned lambs, we found that the meat quality characteristics of foreshank muscle, such as its pH value, redness, water-holding capacity, and intermuscular fat accumulation, as well as its contents of both amino acids and fatty acids, were significantly influenced by supplementing tributyrin. The current research related to the effects of supplementing tributyrin on meat quality characteristics of foreshank muscle of weaned lambs could help with the intensification of nutritional strategies for tributyrin-based livestock systems, improving the meat quality. This experiment aimed to evaluate the effects of supplementing tributyrin (TB) on the meat quality characteristics of foreshank muscle of weaned lambs. A total of 30 healthy weaned Small-Tailed Han female lambs with body weights ranging from 23.4 to 31.6 kg were selected and randomly divided into five groups, and each group consisted of 6 lambs. The control group was fed a basic total mixed ration, while other groups were fed the same ration supplemented with 0.5, 1.0, 2.0, and 4.0 g/kg TB, respectively. The experiment lasted 75 d, including 15 d of adaptation. Foreshank muscle obtained at the same position from each lamb was used for chemical analysis and sensory evaluation. The results showed that supplementing TB increased the muscle contents of ether extract (p = 0.029), calcium (p = 0.030), phosphorus (p = 0.007), and intermuscular fat length (p = 0.022). Besides, TB increased the muscle pH (p = 0.001) and redness (p < 0.001) but reduced the lightness (p < 0.001), drip loss (p = 0.029), cooking loss (p < 0.001), shear force (p = 0.001), hardness (p < 0.001), cohesiveness (p < 0.001), springiness (p < 0.001), gumminess (p < 0.001), and chewiness (p < 0.001). In addition, TB increased the muscle content of inosine-5′-phosphate (p = 0.004). Most importantly, TB increased the muscle contents of essential amino acids (p < 0.001). Furthermore, TB increased the saturated fatty acids level in the muscle (p < 0.001) while decreasing the unsaturated fatty acids content (p < 0.001). In conclusion, supplementing TB could influence the meat quality of foreshank muscle of weaned lambs by modifying the amino acid and fatty acid levels. [ABSTRACT FROM AUTHOR]

Simple Summary: Broilers are important poultry, and recent muscle abnormalities in broilers, such as the emergence of spaghetti meat (SM), have posed challenges to the poultry industry. This condition has received less research attention compared to similar abnormalities, such as wooden breast and white striping. Therefore, in this study, we systematically compared the differences in appearance, meat quality, muscle fiber characteristics, and metabolic components between SM and normal tissues. The results showed that compared with the normal group, the SM group had softer meat quality, and significantly higher yellowing and brightness, while pH and protein levels were significantly lower. Key differential metabolites, including 14,15-DiHETrE and L-malic acid, as well as key metabolic pathways related to inflammation and oxidative stress, such as linoleic acid, arachidonic acid, phenylalanine, and histidine metabolism, are associated with SM. This study provides valuable insights into the muscle characteristics of SM and helps identify potential mechanisms and nutritional regulatory targets of SM myopathy. Spaghetti meat (SM) is a newly identified muscle abnormality that significantly affects modern broiler chickens, consequently exerting a substantial economic impact on the poultry industry worldwide. However, investigations into the meat quality and the underlying causative factors of SM in broilers remain limited. Therefore, this study was undertaken to systematically evaluate meat quality and muscle fiber characteristics of SM-affected meat. To elucidate the disparities between SM-affected and normal (NO) muscles in broiler chickens reared under identical conditions, we selected 18 SM-affected breast tissues and 18 NO breast tissues from 200 broiler chickens raised according to commercial standards under the same conditions for our study. The results showed that compared with the NO group, the muscle surface of the SM group lost integrity, similar to strip and paste. The brightness and yellowness values were significantly higher than those of the NO group. On the contrary, the shear force and protein were significantly lower in the SM group. Microscopic examination revealed that the muscle fibers in the SM group were lysed, necrotic, and separated from each other, with a large number of neutrophils diffusely distributed on the sarcolemma and endometrium. Thirty-five significantly different metabolites were observed in the breast muscles between both groups. Among them, the top differential metabolites—14,15-DiHETrE, isotretinoin, L-malic acid, and acetylcysteine—were mainly enriched in lipid metabolism and inflammatory pathways, including linoleic acid, arachidonic acid, phenylalanine, and histidine metabolism. Overall, these findings not only offer new insights into the meat quality and fiber traits of SM but also contribute to the understanding of potential mechanisms and nutritional regulators for SM myopathy. [ABSTRACT FROM AUTHOR]

Simple Summary: This study investigated the impact of terminal sire (Dorset) use and supplementation with agro-byproducts, specifically corn gluten feed and soy hull, on the carcasses and meat quality of landrace hair sheep (Barbados Blackbelly and St. Croix) under rotational grazing. The crossbred lambs had greater carcass weights and more substantial wholesale cuts from the shoulder, rack, loin, and leg than their purebred counterparts. The purebred supplemented lambs showed comparable enhancements in their carcass characteristics to those of the crossbred lambs. Fresh lamb from the purebred animals displayed a more vivid red and yellow hue compared to the crossbred lambs. The meat from the purebred lambs was found to be softer than that from their crossbred counterparts. Supplementation played a more crucial role than crossbreeding in enhancing carcass quality under the conditions of these experiments. The protein content was notably higher in the meat from the crossbred lambs, while the supplemented lambs produced meat with an increased fat content. Pasture-only lambs had elevated levels of omega-3 and omega-6 fatty acids, displaying a healthier fatty acid profile than those receiving supplementary agro-byproducts. However, they benefited from the improved lipid oxidation stability and texture properties of the meat. The supplement type had no effects on the carcass characteristics, but it affected the meat composition. The effects of breed type (purebred or crossbred) and supplementation of agro-byproducts on the growth, carcass characteristics, and meat quality of landrace hair (Barbados Blackbelly; BB and St. Croix; SX) lambs was evaluated. Thirty-six 7.5-month-old purebred hair (BB and SX; body weight = 24.1 ± 4.26 kg) and terminal sire (Dorset; DO) crossbred lambs (DO × BB and DO × SX; body weight = 31.4 ± 3.50 kg) rotationally grazed predominantly on Jesup tall fescue pasture during spring with or without agro-byproduct supplementation (soyhull or corn gluten feed at 2% of BW). Following a 77d grazing period, the lambs were harvested, and their carcass characteristics and meat composition were evaluated. Both supplementation and crossbreeding significantly increased their carcass weight and primal cuts, whereas only supplementation increased (p < 0.01) the dressing percentage, and crossbreeding increased the shear force (p < 0.01). Regardless of breed type, supplementing agro-byproducts improved the lipid oxidation stability and texture properties of the fresh lamb, whereas the pasture-only lambs had healthier fatty acid profiles compared with the supplemented lambs. The results indicate that both terminal sire crossbreeding and byproduct supplementation can be used to affect the carcass characteristics and meat composition of landrace hair sheep lambs. [ABSTRACT FROM AUTHOR]

Simple Summary: The surging global demand for beef products has spurred farmers to adopt practices enhancing both quantity and quality, particularly in selecting cattle breeds. This study addresses a knowledge gap in understanding how beef and dairy crossbreeding respond to varying energy nutrition, which is crucial for designing effective tropical feeding regimes. Over six months with thirty-six steers, the research examined the impact of different dietary metabolizable energy densities on two crossbred beef cattle—Holstein Friesian and Charolais. Despite fewer carcass yields, Holstein Friesian crossbreds demonstrate superior eating quality, reduced meat drip loss, elevated meat iron content, and lower Warner–Bratzler shear force due to increased intramuscular fat. Meat color remains consistent across beef and dairy crossbreeding. Higher dietary energy density positively influences nutrient intake and rumen fermentation but unaffected growth performance and carcass traits. The study highlights the potential of Holstein Friesian crossbred steers in intensive beef production, providing valuable insights for achieving quality meat outcomes under the Thai feedlot management system. This study determines the effects of varying dietary metabolizable energy densities on Holstein Friesian and Charolais crossbred beef cattle in fattening phases. The research focuses on nutrient utilization, ruminal fermentation, growth performance, carcass traits, and meat quality. Thirty-six steers were used in the feeding trial that lasted for six months according to a 2 × 3 factorial arrangement in a randomized complete block design (Factor A, cattle breeds (Holstein Frisian, Charolais crossbred); B, metabolizable energy density (10.5, 11.1 and 11.8 MJ/kg DM)) with six replications. The dietary energy density had no interaction with the cattle breeds (p > 0.05). Despite fewer carcass yields, Holstein Friesian crossbreds indicate superior eating quality to Charolais crossbreds on drip loss, meat iron content, and Warner–Bratzler shear force due to increased intramuscular fat content (p < 0.05) with similar meat color (p > 0.05). Increased dietary energy density positively impacts nutrient and energy intake and rumen fermentation (p < 0.05) but did not affect growth and carcass traits (p > 0.05). This research suggests the potential of Holstein Friesian crossbreds for intensive beef production, providing valuable insights into optimal feeding strategies for achieving quality meat outcomes. On-farm feeding trials are needed to develop a practical and economical Thai beef feedlot management system [ABSTRACT FROM AUTHOR]

Simple Summary: The way poultry are fed affects the fatty acid profile of the meat. A sufficient supply of zinc (Zn) is crucial because this element is capable of modulating fatty acid metabolism and can affect the dietary quality of meat. Our study aimed to determine whether Zn glycine chelate used in the diets of Ross 308 broiler chickens can improve the dietary quality of meat due to a beneficial modification of the fatty acid profile. Using statistical methods, we confirmed the effect of the form (sulphate vs. glycine chelate) and/or quantity of Zn used (100% or 50% of the requirement) on the fatty acid profile and dietary quality of thigh meat. However, our results imply that it is sufficient to supply any form of Zn in the amount satisfying 50% of the chicken requirements for Zn to ensure satisfactory dietary quality of their meat. Studies concerning nutritional strategies for the modification of the dietary quality of meat by altering the fatty acid profile are significant to consumers, as such modification can produce good-quality meat for safe consumption without increasing the risk of diet-related civilisational diseases and can even contribute to reducing such a risk. The present study aimed to investigate the effect of mineral (sulphate) or organic (glycine chelate) forms of Zn used in quantities covering 100% or 50% of the Zn requirement on the fatty acid profile of the thigh muscles of Ross 308 broiler chickens. We also analysed the dietary value of this meat based on its fatty acid profile. The experimental factors did not influence the content of basic chemical components and the meat's pH. Although, in terms of statistics, the presented study supports the statement that the form (sulphate vs. glycine chelate) and/or amount of Zn used (100% or 50% of the requirement) affects the fatty acid profile and dietary value of thigh meat, the results imply that the requirement of Ross 308 broiler chickens for Zn was also covered in full when in it was used in amounts covering 50% of the requirement, irrespective of the form in which Zn was used. However, it cannot be explicitly confirmed that the form of Zn affects the analysed parameters of thigh meat. [ABSTRACT FROM AUTHOR]

Simple Summary: It was confirmed that electronarcosis (EE) is a better method of pre-slaughter stunning for the meat quality of Arapaima gigas fillets from fish farming; the other methods are ice asphyxiation (IA), air asphyxiation (AA) and hypothermia followed by bleeding (HB), which showed fewer interesting results. Data were obtained from a pH analysis, rigor mortis index (RI), water activity (Aw), instrumental texture, blood glucose and instrumental colourimetry. During the study, for up to 15 days of refrigerated storage, the methods provided pH values below 6.0. EE resulted in better texture assignments in the fillets. The blood glucose values indicate that the fish subjected to EE were less stressed. Regarding instrumental colourimetry, the fillets submitted to EE and HB showed greater luminosity, those subjected to AA exhibited greater red-green colour intensity and those subjected to EE showed greater yellow-blue colour intensity. Therefore, the fish did not suffer stress with electronarcosis, and the fillets showed better preservation, juiciness and tenderness. The aim of this study was to evaluate the influence of different stunning methods on the meat quality of Arapaima gigas fillets from fish farming. A total of 48 specimens of A. gigas in the weight class 11.1 to 14.0 kg were investigated; these fish were subjected to different stunning methods for slaughter: ice asphyxia (IA), air asphyxia (AA), electronarcosis (EE) and hypothermia followed by bleeding (HB). Then, data were obtained from the analysis of pH, rigor mortis index (RI), water activity (Aw), instrumental texture (compression strength, firmness and adhesiveness) and blood glucose and via instrumental colourimetry. During the study, for up to 15 days of refrigerated storage, the methods provided pH values below 6.0. A. gigas submitted to EE and HB remained longer in the pre-rigor status. In addition, they expressed lower percentages of Aw. The EE method resulted in better texture assignments in the fillets. The blood glucose values indicated that the fish subjected to EE were less stressed. Concerning instrumental colourimetry, the fillets submitted to EE and HB showed greater luminosity; the fillets subjected to AA showed greater red-green colour intensity, while the fillets subjected to EE showed greater yellow-blue colour intensity. Therefore, the fish did not suffer stress with electronarcosis, and the fillets showed better preservation, juiciness, and tenderness. [ABSTRACT FROM AUTHOR]

Simple Summary: We hypothesised a positive effect of adding raspberry seed oil into the feed of purebred Termond White rabbits on slaughter performance traits, plasma lipid concentration and meat quality. In each group, the experimental animals were fed a complete pelleted feed. Rabbits in the first experimental group received a feed ration enriched with a 1% addition of raspberry seed oil, while rabbits in the second experimental group were given a 2% addition of the same oil. The addition of this oil did not significantly affect the slaughter performance traits of the rabbits. It also did not significantly affect the fat content, shear force, hardness, springiness, cohesiveness or chewiness of the meat obtained from the rabbits' longissimus lumborum muscle. However, the addition of raspberry seed oil significantly reduced the levels of tetradecenoic acid and trans-palmitoleic acid. An increase in the linoleic acid content of rabbit meat was also observed. This study showed that feeding pellets containing an oil supplement with a high content of unsaturated fatty acids had a positive effect on rabbits' plasma lipid levels. The addition of raspberry seed oil might lead to an effective reduction in cholesterol and triglyceride levels in rabbits' blood. The purpose of the study was to determine the effects of raspberry seed oil on the slaughter performance traits, plasma lipid concentration and meat quality of purebred Termond White rabbits (n = 42; 18♂, 24♀). In each group (3 × n = 14; 6♂, 8♀), the experimental animals were fed a complete pelleted feed with constant access to drinking water. Rabbits in the first experimental group received a feed ration enriched with a 1% addition of raspberry seed oil, while rabbits in the second experimental group were given a 2% addition of the same oil. These animals were slaughtered on day 84. The addition of raspberry seed oil did not significantly affect the slaughter performance traits of the rabbits (p > 0.05). It also did not significantly affect the fat content, shear force, hardness, springiness, cohesiveness or chewiness of the meat obtained from the rabbits' longissimus lumborum muscle. However, the experiment showed that the addition of raspberry seed oil had a significant effect on the fatty acid profile of rabbit meat (p ≤ 0.05). Even a small share of this oil in the feed ration significantly increased the level of linoleic acid (p ≤ 0.05). This study showed that feeding pellets containing an oil supplement with a high content of unsaturated fatty acids had a positive effect on rabbits' plasma lipid levels. [ABSTRACT FROM AUTHOR]

Simple Summary: Pheasants are medium-sized birds from Asia and southeastern Europe that were introduced to many countries around the world. In Poland, they are mainly used as game birds. The farm rearing of pheasants for meat production is small in scale. They are also kept in parks and gardens. Due to their attractive appearance, including multi-colored plumage, especially in males, they are popular birds and are often kept by hobbyists. The aim of this study was to determine the effects of slaughter age (the duration of the rearing period) and sex on the carcass weight and composition, physicochemical properties, meat texture, and biometric traits of the leg bones (femur and tibia) of common pheasants kept on farms. The results indicate that the sex of the birds has a greater influence on these traits than the slaughter age. The numerous differences in the carcass composition, basic chemical composition, texture, and physicochemical characteristics of the meat of male and female pheasants indicate that they differ in their nutritional value and suitability for processing. The aim of this study was to determine the effects of slaughter age and sex on the carcass characteristics, meat quality parameters, and leg bone dimensions of common pheasants. The study material consisted of 40 common pheasants, including 10 males and 10 females at 12 weeks of age and 10 males and 10 females at 15 weeks of age. The birds were kept on a farm in a semi-intensive system. The slaughter age had significant effects on the eviscerated carcass weight; the percentage of skin with subcutaneous fat; the wings percentage; electrical conductivity (EC24); the work required to cut the samples (cutting work); redness (a*); the intramuscular fat content in the breast meat; and the protein, intramuscular fat, water, and collagen contents in the leg meat. The sex of the pheasants had significant effects on the eviscerated carcass weight; the contents of leg muscles, skin with subcutaneous fat, and wings in the carcasses; and the electrical conductivity, thermal loss, lightness (L*), and redness (a*) of the breast muscles. It also significantly affected the protein and water contents of the pectoral and leg muscles, the intramuscular fat contents of the leg muscles, the texture traits of the pectoralis major muscle, and all femur and tibia bone dimensions. The results indicate a greater influence of sex compared to slaughter age on the pheasant traits studied. We confirmed the occurrence of a clearly marked sexual dimorphism in birds of this species. Both factors (slaughter age and gender) have significant effects on the nutritional and technological value of pheasant meat. The few studies on meat texture and the dimensions of pheasant leg bones indicate a need for continued research in this area in the future. [ABSTRACT FROM AUTHOR]

Simple Summary: Succinate is an important product of the fermentative metabolism of dietary fiber, and similar to propionate, high levels of succinate in the gut modulate the body's inflammatory response, glucose tolerance, and lipid metabolism. Our study showed that the addition of 1% succinate to pig diets promoted growth and fat deposition capacity without affecting feed intake, remodeled the fatty acid content of the longissimus dorsi muscle, and consequently improved meat quality. Further, we isolated and cultured primary porcine preadipocytes. The results showed that succinate increased the expression of genes related to adipogenic differentiation while decreasing the levels of genes related to lipolysis and promoting the formation of cellular lipid droplets. Mechanistically, dietary supplementation with succinate increases succinylation modification in adipose tissue to promote facilitated lipogenesis. This suggests that it is feasible and important to improve fatty acids and meat quality in porcine muscle through dietary succinate supplementation. Succinate, one of the intermediates of the tricarboxylic acid cycle, is now recognized to play a role in a broad range of physiological and pathophysiological settings, but its role in adipogenesis is unclear. Our study used Bama miniature pigs as a model to explore the effects of succinate on performance, meat quality, and fat formation. The results showed that adding 1% succinate significantly increased the average daily gain, feed/gain ratio, eye muscle area, and body fat content (p < 0.05), but had no effect on feed intake. Further meat quality analysis showed that succinate increased the marbling score and intramuscular fat content of longissimus dorsi muscle (LM), while decreasing the shear force and the cross-sectional area of LM (p < 0.05). Metabolomics analysis of LM revealed that succinate reshaped levels of fatty acids, triglycerides, glycerophospholipids, and sphingolipids in LM. Succinate promotes adipogenic differentiation in porcine primary preadipocytes. Finally, dietary succinate supplementation increased succinylation modification rather than acetylation modification in the adipose tissue pool. This study elucidated the effects of succinate on the growth and meat quality of pigs and its mechanism of action and provided a reference for the role of succinate in the nutrition and metabolism of pigs. [ABSTRACT FROM AUTHOR]

Simple Summary: Vitamin D3 is an essential trace element in the poultry diet and plays an important role in healthy poultry production. Establishing the amount of VD3 required in the yellow feather broiler diet is important for actual production. This experiment aims to determine the appropriate amount of VD3 for enhancing growth performance, tibia traits, slaughter performance, and meat quality and to further explore the metabolic pattern of VD3 in broilers by 16S rRNA and liver transcriptome sequencing. This study aimed to assess the effects of different dietary vitamin D3 (VD3) levels on growth and carcass performance, tibia traits, meat quality, and intestinal morphology of yellow-feathered broilers. One-day-old broilers (n = 1440) were assigned into four treatment groups with six replicates per group, and each replicate contained 60 chicks. Dietary VD3 significantly improved the growth performance and carcass traits of broilers, and only low-dose VD3 supplementation decreased the abdominal fat percentage. High-dose VD3 supplementation improved intestinal morphology in the finisher stage, while the b* value of breast muscle meat color decreased markedly under VD3 supplementation (p < 0.05). Serum Ca and P levels and the tibia composition correlated positively with dietary VD3 supplementation at the early growth stage. The weight, length, and ash contents of the tibia increased linearly with increasing dietary VD3, with maximum values achieved in the high-dose group at all three stages. Intestinal 16S rRNA sequencing and liver transcriptome analysis showed that dietary VD3 might represent an effective treatment in poultry production by regulating lipid and immune-related metabolism in the gut–liver axis, which promotes the metabolism through the absorption of calcium and phosphorus in the intestine and improves their protective humoral immunity and reduces infection mortality. Dietary VD3 positively affected the growth—immunity and bone development of broilers during the early stage, suggesting strategies to optimize poultry feeding. [ABSTRACT FROM AUTHOR]

Simple Summary: This review highlights the benefits of using valuable alternative feeds such as crop residues, silage, grasses, hay, browse, plant leaves, shrubs, and agro-industrial by-products in small ruminants' diets. Alternative feeds can significantly improve the productivity and reduce carbon footprints and GHG fluxes of small ruminant farms, making them both environmentally friendly and cost-effective. Additionally, these alternative feeds possess antioxidant, antimicrobial, and antiseptic properties that can enhance the quality of the meat and milk produced. Small ruminants, such as sheep (Ovisaries) and goats (Capra hircus), contribute to approximately 475 million metric tons of carbon dioxide equivalent (MtCO2e) greenhouse gas (GHG) emissions, accounting for approximately 6.5% of the global emissions in the agriculture sector. Crop residues, silage, grasses, hay, browse, plant leaves, shrubs, agro-industrial by-products, poultry litter, and other alternative feed sources are frequently utilized for small ruminant production. The use of these valuable alternative feeds can significantly improve animal productivity and reduce carbon footprints and GHG fluxes, making it both environmentally friendly and cost-effective. Additionally, these alternative feeds possess antioxidant, antimicrobial, and antiseptic properties that can enhance the quality of the meat and milk produced. By impacting the bacteria involved in ruminal biohydrogenation, alternative feeds can reduce methane emissions and contribute to a decrease in the carbon footprint. Overall, the use of alternative feed sources for small ruminants generally improves their apparent nutrient digestibility and productivity, and has an impact on the production of greenhouse gases, especially methane. Finally, this review recommends evaluating the economic analysis of reducing methane emissions in small ruminants by utilizing different feed sources and feeding techniques. [ABSTRACT FROM AUTHOR]

Simple Summary: As demand for lamb is increasing, shortening the growth cycle and increasing meat production in lambs are major concerns today. Protein and energy are the two nutrients that most directly drive meat production in animals. In lambs, however, too few applications are available through nutrient combinations. We believe it is feasible to encourage animals to improve meat production performance by regulating the simplest nutrients in feed. In this experiment, we investigated the effects of three dietary ingredients with protein-to-fat ratios on growth, slaughter performance, fat deposition and meat quality of Small-Tail Han lambs. The aim of the current research was to gain insights/provide ideas for enhancing nutrient combination effects to improve animal production performance. The purpose of this study was to investigate the effects of feed ingredients with different protein-to-fat ratios on growth, slaughter performance and meat quality of Small-Tail Han lambs. Forty-five Small-Tail Han lambs (♂) (BW = 34.00 ± 2.5 kg, age = 120 ± 9 d) were randomly divided into groups with three different experimental treatments: (1) PF 5, with the ratio of protein to fat (CP:EE) of 50 to 5; (2) PF10, CP: EE = 50:10; (3) PF20, CP: EE = 50:20. Each treatment group had 15 lambs, and each sheep was a repeat. This experiment lasted for 65 days, with feed intake recorded daily, and animals being weighed on days 0, 30, and 65. At the conclusion of the experiment, eight lambs from each group were slaughtered to assess slaughter performance and meat quality. The results showed that the average daily gain (ADG) of the three groups were 315.27, 370.15 and 319.42 g/d, respectively. The PF10 group had the highest ADG (370.15 g) (p < 0.05). Forestomach weights (1216.88 g) of the PF10 group were significantly higher than those of the other groups (p < 0.05). There were no differences (p > 0.05) in fat percentages in various parts of body among treatments. Feed conversion of the PF10 group was higher (p < 0.05) than that of PF 5 and PF 20 groups. Furthermore, the PF10 group had a higher (p > 0.05) carcass weight and slaughter rate and there were few differences between the other groups in terms of dry matter intake, meat quality, organ weight, and fat deposition (p > 0.05). The protein–energy supplement with protein-to-fat ratio, PF10 appeared to be more desirable to promote the growth and development in Small-Tail Han Lambs. [ABSTRACT FROM AUTHOR]

Simple Summary: The Lidia breed is an autochthonous Spanish breed linked to the pasture-based dehesa system, where extensive livestock farming is practiced and plays an important role in ecosystem conservation and rural development. This system is linked to the conservation of biodiversity and sustainable agricultural practices. However, it faces important challenges that make it necessary to explore new strategies to help farmers. In this study, we sought to understand the carcass and meat traits (technological and sensorial) as a strategy that would allow it to compete and differentiate itself from other meats. We used 300 Lidia females slaughtered at different ages. Age at slaughter influenced meat quality, with particular importance on sensory variables such as flavor, juiciness, overall tenderness and overall acceptability. Technological variables were acceptable and the results of a trained sensory panel pointed to the good qualities of this meat. To our knowledge, this is the first work evaluating carcass traits and the technological and sensory quality of meat with a large sample of animals of the Lidia breed. The aim of this study was to assess the carcass and meat quality of female Lidia cattle slaughtered at different ages, in order to deepen our understanding of the breed's unique characteristics. The effect of slaughter age on carcass traits and meat quality attributes of m. Longissimus was investigated in Lidia heifers (n = 200) and cows (n = 100) reared and finished in an extensive system. The animals were slaughtered at 24–36 months (Heifer I), 36–48 months (Heifer II) or >48 months (Cull cow). The carcasses (~120 kg) presented poor conformation (O, O+) and medium fatness (2, 2+). The dissection of the 6th rib yielded mean values of 58.6%, 14.3% and 24.8% for lean, fat and bone, respectively. The cows had a higher proportion of dissectible fat (p < 0.05). Subcutaneous fat was classified as dark and yellowish, and meat (aged for 21 days) as dark (L* = 25.5), reddish (a* = 14.4) and moderately yellowish (b* = 12.9), with acceptable water-holding capacity (TL = 5.34%; DL = 0.97%; PL = 8.9%; CL = 22.1%) and intermediate tenderness (WBSF = 4.6 kg/cm2). The b* value of meat was higher (p < 0.05) in cull cows. The meat of cull cows was more yellowish (p < 0.05) and obtained higher scores for flavor (p < 0.05), juiciness p < 0.01), overall tenderness (p < 0.001) and overall acceptance (p < 0.001). [ABSTRACT FROM AUTHOR]

Simple Summary: Early weaning is a practice that holds the potential to enhance beef cattle production systems. It aims to improve the reproductive performance of cows in the subsequent breeding season while minimizing the impact on weaned calves when they are appropriately nutritionally managed. This study aimed to compare the effects of early weaning (weaning at 150 days; EW) and conventional weaning (weaning at 240 days; CW) on the growth, carcass characteristics, and meat quality of Nellore bulls. A total of 74 non-castrated calves were assigned to an EW (n = 37) or CW (n = 37) strategy. During approximately 400 days in the growth phase, both groups received supplementation during grazing, followed by a finishing period in a feedlot for 87 days. The results showed that calves in the EW group were lighter than the CW group at the time of conventional weaning, yet this weight difference did not impact their growth or meat quality during the fattening phase. This study suggests that early weaning, combined with adequate supplementation, can be a viable and sustainable approach in beef cattle production without compromising the animals' productive development or meat quality. This study compared early weaning (EW; 150 days) with conventional weaning (CW; 240 days) in Nellore young bulls, evaluating performance, carcass characteristics, and meat quality. A total of 74 non-castrated male calves were divided into two weaning strategies: EW (n = 37) and CW (n = 37). During the growth phase, which lasted 454 ± 14 d for EW calves and 359 ± 16 d for CW calves, animals received a protein-energy supplement at a ratio of 5 g per kg of body weight while grazing Brachiaria brizantha cv. Marandu. The animals were managed for an 87d finishing phase in three collective feedlot pens, with a 3-week adaptation protocol, starting with corn silage to a concentrate ratio of 55:45 and reaching a ratio of 30:70 in the final diet. Body weight, average daily gain (ADG), dry matter intake (DMI), feed efficiency (FE), carcass characteristics, and meat quality were evaluated. The EW group was approximately 44 kg lighter than the CW at the time of conventional weaning (p < 0.001). However, this weight difference did not influence ADG, DMI, and FE in the finishing phase. No significant differences were observed in carcass characteristics such as yield percentage, loin area, subcutaneous fat thickness, and meat quality, except for the weight of primal cuts, which was greater in the CW group (p < 0.001). Thus, although calves weaned early are lighter throughout subsequent production phases than those weaned conventionally, performance, efficiency, carcass yield, and meat quality are not affected. [ABSTRACT FROM AUTHOR]

Simple Summary: Organic acids and essential oils have been shown to be effective alternatives to antibiotic growth promoters in pig production. Organic acids and essential oils have antibacterial, antiviral, and antioxidant properties. The article will focus on the effectiveness of organic acids, essential oils, and their blends in pig diets as alternative antibiotic growth promoters. Furthermore, the effects of organic acids, essential oils, and their blends on growth performance, oxidative stress, and meat quality are examined. Organic acids and essential oils, which have antimicrobial properties, can be used in place of antibiotic growth promoters. The use of organic acids and essential oils as growth promoters enhances pig welfare and aids in the fight against antimicrobial resistance. Over the years, the use of management and feeding strategies to enhance pig productivity while minimizing the use of antibiotic growth promoters has grown. Antibiotic growth promoters have been widely used as feed additives to reduce diet-related stress and improve pig performance. However, increasing concern about the consequences of long-term and increased use of antibiotic growth promoters in animal production has led to a paradigm shift towards the use of natural organic alternatives such as plant essential oils and organic acids in pig nutrition to enhance growth. Antibiotic growth promoters endanger human health by allowing multidrug-resistant genes to be transferred horizontally from non-pathogenic to pathogenic bacteria, as well as directly between animals and humans. Scientific research shows that alternative growth promoters such as essential oils and organic acids appear to improve pigs' ability to prevent pathogenic bacteria from colonizing the intestinal system, stabilizing the gut microflora and promoting eubiosis, as well as improving immunity and antioxidant stability. The purpose of this review was to provide an in-depth review of organic acids and essential oils as growth promoters in pig production, as well as their effects on productivity and meat quality. Organic acids and essential oils in pig diets are a safe way to improve pig performance and welfare while producing antibiotic-free pork. [ABSTRACT FROM AUTHOR]

Simple Summary: There is little information about the consequences of variation in birth weight due to intrauterine growth on postnatal growth and development of lambs. This study, therefore, investigated the effects of birth weight on postnatal growth, fattening performance, muscle mass development, muscle fibre characteristics, and meat quality in Karayaka lambs. The results of the study show that heavier-born lambs develop better, which is reflected in fattening performance and carcass characteristics. Although there was no difference in meat quality parameters, it was found a significant difference in the fibre area of Type I fibres in the longissimus thoracis et lumborum muscle due to birth weight. The results of the study provide essential insights into the complex relationship between birth weight and various physiological values such as carcass parameters, muscle mass development, and muscle fibre characteristics in post-weaning fattening of Karayaka lambs. This investigation aimed to assess the influence of birth weight on post-weaning fattening performance, meat quality, muscle fibre characteristics, and carcass traits in Karayaka lambs. The study categorized the lambs into three distinct groups based on birth weight: low birth weight (LBW), medium birth weight (MBW), and high birth weight (HBW). Throughout the fattening phase, the lambs were given ad libitum access to food and water, culminating in the slaughter at the end of the study. Following slaughter, warm and cold carcasses were weighted, and specific muscles (longissimus thoracis et lumborum [LTL], semitendinosus [ST], and semimembranosus [SM]) were isolated for the evaluation of muscle weights, muscle fibre types (Type I, Type IIA, and Type IIB), and muscle fibre numbers. Carcass characteristics were also determined, including eye muscle (LTL) fat, loin thickness, and meat quality characteristics, such as pH, colour, texture, cooking loss, and water-holding capacity. The statistical analysis revealed highly significant differences among the experimental groups concerning muscle weights and warm and cold carcass weights (p < 0.01), with the lambs in the HBW group exhibiting a notably higher carcass yield (in females: 45.65 ± 1.34% and in males: 46.18 ± 0.77%) and LTL, ST, and SM (except for female lambs) muscle weights than the lambs in LBW group (p < 0.01). However, apart from the texture of LTL and ST muscles, no significant differences in meat quality parameters were observed among the treatment groups (p > 0.05). Notably, the birth weight of lambs did not impart a discernible effect on the total number and metabolic activity of muscle fibres in LTL, ST, and SM muscles. Nonetheless, a noteworthy distinction in the fibre area of Type I fibres in the LTL muscle of male lambs (LBW: 30.4 ± 8.9, MBW: 29.1 ± 7.3 and HBW; 77.3 ± 15.4) and in the ST muscle of female lambs (LBW: 44.1 ± 8.1, MBW: 38.8 ± 7.7 and HBW: 36.9 ± 7.1) were evident among the birth weight groups (p < 0.05). The study also found that the mean fat thickness values of eye muscles in Karayaka lambs, as obtained by ultrasonic tests, were below the typical range for sheep. In synthesis, the outcomes of this study underscore the considerable impact of birth weight on slaughtered and carcass weights, emphasizing the positive association between higher birth weights and enhanced carcass yield. Remarkably, despite these pronounced effects on carcass traits, the birth weight did not demonstrate a statistically significant influence on meat quality or overall muscle fibre characteristics, except for the area of Type I fibres in the LTL muscle. This nuanced understanding contributes valuable insights into the intricate relationship between birth weight and various physiological and carcass parameters in Karayaka lambs undergoing post-weaning fattening. [ABSTRACT FROM AUTHOR]

Simple Summary: This study explores the impact of pre-slaughter stress on pigs, focusing on non-ambulatory, non-injured (NANI) pigs, and pigs showing no apparent anomalies (non-NANI). Pre-slaughter stress is known to affect animal welfare and meat quality. NANI pigs, often disabled or injured, exhibit higher body temperatures and significant blood count changes, indicating elevated stress levels. The study correlates these physiological markers with meat quality parameters, revealing that NANI pigs experience abnormalities in meat characteristics. The findings emphasize the potential use of blood biomarkers as predictive tools for evaluating pig welfare during handling, leading to improved practices and, consequently, better meat quality. This research aims to contribute to enhanced animal welfare and more efficient pork production practices. The study aimed to investigate the physiological and meat quality differences between Non-Ambulatory, Non-Injured (NANI), and without apparent abnormalities (non-NANI) pigs in a commercial slaughterhouse setting, focusing on the impact of stress and health conditions on the overall well-being and meat quality of the animals. A total of 241 surgically castrated crossbred male pigs from Southern Brazil were analyzed, with 131 non-NANI pigs and 110 NANI pigs. Infrared orbital temperature, rectal temperature, hematological parameters, and meat quality measurements were collected. Statistical analysis included ANOVA tests and principal component analysis (PCA). NANI pigs exhibited significantly higher infrared orbital temperatures and rectal temperature (p < 0.01). Hematological analysis revealed higher levels of hemoglobin, hematocrit, and red blood cells in NANI pigs (p < 0.05). White blood cell count and lactate dehydrogenase were significantly elevated in NANI pigs (p < 0.01), indicating potential infections or inflammatory responses. Meat quality parameters showed that NANI pigs had lower pH values, higher luminosity, and increased drip loss (p < 0.01), reflecting poorer water retention and potential muscle glycogen depletion. The study highlights the physiological and meat quality differences between NANI and non-NANI pigs, emphasizing the impact of stress, health conditions, and handling procedures on the animals. Blood biomarkers proved valuable in assessing physiological stress, immune response, and potential health issues in pigs, correlating with meat quality abnormalities. Utilizing these biomarkers as predictive tools can enhance animal welfare practices and contribute to improving meat quality in the swine industry. [ABSTRACT FROM AUTHOR]

Simple Summary: There are few reports on local pig breeds in Guizhou province. In this work, the population structure, genetic diversity, and selection characteristics of three foreign pig breeds and seven Guizhou local pig breeds were studied. Principal component analysis, adjacent tree analysis, and ADMIXTURE analysis showed that Chinese and Western pig breeds had different ancestral sources. Jianhe White Xiang pig (JHBX) had a distant genetic relationship with the other six local pig breeds in Guizhou province and had unique genetic characteristics. The genetic diversity of the JHBX population was low, and the genetic diversity of the remaining six Chinese native pig populations was generally at a moderate level. In addition, we also screened the candidate genes that affect the coat color phenotype of pigs in Guizhou province through selection signals. Our findings will advance our understanding of the genetic mechanisms underlying these germplasm characteristics. The local pig breeds in Guizhou possess exceptional meat quality, robust adaptability, and resilience to harsh feeding conditions, making them ideal for producing high-quality pork. With over 10 local pig breeds in the region, we focused on 7 specific breeds: Baixi pigs (BX), Congjiang Xiang pigs (CJX), Guanling pigs (GL), Jianhe White Xiang pigs (JHBX), Jiangkou Luobo pigs (JKLB), Kele pigs (KL), and Qiandong Hua pigs (QDH). Unfortunately, these breeds face threats such as introduced species and inbreeding, resulting in a decline in population size and numbers. To better protect and utilize these breeds, we employed genome-wide single-nucleotide polymorphism (SNP) markers to investigate the population structure, genetic diversity, and selection characteristics of 283 pigs across these seven breeds. Our findings revealed distinct ancestral sources between Chinese and Western pig breeds, as demonstrated by principal component analysis, adjacent tree analysis, and ADMIXTURE analysis. Notably, JHBX exhibited a distant genetic relationship from the other six local pig breeds in Guizhou province, showcasing unique genetic characteristics. While the genetic diversity of the six Chinese native pig populations, excluding JHBX, was generally moderate in Guizhou province, the JHBX population displayed low genetic diversity. Therefore, it is imperative to intensify selection efforts to prevent inbreeding decline in JHBX while further enhancing the protection measures for the other six pig populations. Additionally, we identified candidate genes influencing the size disparity among pigs in Guizhou province through signal selection. Our study outcomes serve as a reference for developing effective conservation and utilization plans for pig breeds in Guizhou province and deepen our understanding of the genetic mechanisms underlying pig body size. [ABSTRACT FROM AUTHOR]