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Meat rabbits are a small herbivorous livestock and have been popularly raised in China for producing high-quality meat. Therefore, it is economically important to genetically improve both carcass performance and meat quality in meat rabbits. However, we still know less about the underlying candidate genes that may determine phenotypic variation on carcass and meat traits of meat rabbits. The main objective of this study was to identify candidate genes whose mRNA expression levels may be significantly involved in regulating carcass and meat traits of meat rabbits based on the transcriptome-wide association studies (TWAS). Five carcass traits of the carcass weight (CW), dressing out percentage (DP), cut weight of hind legs (LW), weight ratio of cut hind legs to carcass (RLW), and weight of visceral and interscapular fat (WF), as well as two meat traits of the drip loss (DL) and cooking loss (CL) were phenotyped in a F1 crossbred population (N = 119) between Zika rabbits and Sichuan White rabbits. The effects of mRNA expression levels of a total of 10,288 genome-wide genes on these seven traits were statistically estimated using the mixed linear model, in which the polygenic background effects were accounted for. Our results revealed two candidate genes (RDH5 and MTARC2) that were statistically significantly associated with LW trait (the adjusted p values <0.05), whereas no gene reached the statistically significant threshold for all the remaining six traits. Because of the relatively small sample size analyzed, we alternatively selected 20 candidate genes with the lowest p values for every trait and subjected them to functional enrichment analyses, which identified three Gene Ontology (GO) terms that were significantly enriched by the candidate genes of CW and RLW traits. In conclusion, this study used TWAS approach to successfully reveal several candidate genes whose mRNA expression levels may be involved in regulating carcass and meat traits in meat rabbits, which are helpful to explore the underlying molecular mechanism in the future studies. [ABSTRACT FROM AUTHOR]

To investigate the effects of nano-oxide zinc (ZnO NPs), spirulina platensis (SP), and their combination on broiler chickens" growth, carcass traits, blood biochemistry, and redox status. A total of 270 Cobb broiler chicks that were one-day-old were allocated into nine equal groups at random. The first group was given a basal diet and functioned as a control group. The other groups were given the basal diet supplemented ZnONPs with 30 or 60 mg/kg diet (groups 2 and 3) or SP with 2 or 4 g/kg diet (groups 4 and 5), and their combination (groups 6 to 9). Results showed that supplementation with ZnONPs and SP, individually or combined improved daily body weight gain (BWG) and live body weight (LBW). This increase in LBW was associated with reduced feed consumption (FC), leading to an improved feed conversion ratio (FCR). The best outcomes were observed with the higher dose of ZnO NPs (60 mg/kg) or its combination with 4 g/kg SP. High doses of ZnONPs and SP significantly (P≤0.05) reduced abdominal fat and increased relative carcass weight. ZnONPs also improved hemoglobin content and red blood cell count. No significant differences were found in plasma total protein, albumin, globulin, or glucose levels, but liver enzyme activities (AST and ALT) significantly (P≥ 0.01) decreased. Plasma total lipids and triglycerides decreased slightly with ZnONPs or SP supplementation. The activity of the antioxidant enzymes total antioxidant capacity (TAC), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and catalase (CAT) were increased, while malondialdehyde (MDA) levels showed a slight decrease. serum immunoglobulins (IgA, IgM, IgG, IgD, and IgE) were boosted in treated groups, with significant increases (P≤0.05) in IgG, IgD, and IgE with the ZnONPs + SP groups. In conclusion, ZnONPs, SP, and their combination enhanced broiler performance, blood biochemical balance, and antioxidant status, with the best results achieved at 60 mg ZnONPs combined with the two studied levels of SP. [ABSTRACT FROM AUTHOR]

Replacing traditional di-calcium phosphate (DCP) with nanohydroxyapatite (NHA) was investigate as a potential strategy to enhance mineral bioavailability and reduce feed costs. This study explored the impact of varying levels of dietary NHA on broiler chicks' growth performance, carcass traits, digestive tract measurements, and immune organs. A total number of 1080 unsexed one-day-old "Cobb 500" broiler chicks were distributed in a completely randomized design of six treatments with three replicates (60 chicks each). The control group (T1) contained 100% DCP of diet, treatments two (T2) to six (T6) were supplemented with NHA, which represent replacement rates of 100, 80, 60, 40 and 20% of DCP in the basal diet, respectively. The results indicate that broilers fed with 100% DCP demonstrated superior growth performance and carcass weight (P≤0.05) compared to those receiving lower NHA dosages. Specifically, the 100% DCP group achieved higher carcass weight (P≤0.05), while diets containing 80% NHA substitution for DCP resulted in higher carcass percentages. In contrast, birds on lower NHA diets (60 and 40%) exhibited higher giblet percentage (P≤0.05), and lower (P≤0.05) abdominal fat weights were observed at 40% NHA levels. The control group with 100% DCP had a significantly higher (P≤0.05) relative gut weight compared to other treatments. The spleen percentage was notably highest in the group receiving 100% NHA and NHA significantly increased thymus weight and percentage, especially T4, with similar improvements in groups T3, T4, T5, and T6. Additionally, birds fed 40% NHA showed a notable increase in the relative weight and percentage of the bursa compared to other groups. In conclusion, while NHA offer potential benefits in broiler chicken nutrition; further research are needed to determine the optimal dosage, specific conditions, sustainable and environmentally friendly options for incorporating these nanoparticles into broiler chicken feed. [ABSTRACT FROM AUTHOR]

A feeding trial was conducted with the objective of evaluating the effect of replacing wheat bran with cactus pear meal on feed intake, digestibility, growth performance and carcass characteristics of Tigray highland sheep fed a basal diet of mixed grass hay. Twenty uncastrated, growing male sheep (14.56 ± 1.54 kg) were used in a randomized complete block design with five treatments in four replications. Wheat bran was replaced with cactus pear meal at a ratio of 0% (T1), 25% (T2), 50% (T3), 75% (T4) and 100% (T5) on a dry matter basis. The data were analysed using SAS statistical tools. The result showed that there was no statistical difference in feed intake, body weight gain, feed conversion efficiency, digestibility or carcass characteristics among the dietary treatments (P > 0.05). However, crude protein intake was slightly higher in the control sheep group than that of the cactus-containing supplement groups (P < 0.05). Dressing percentage was affected by diet (P < 0.05), while the rib-eye muscle area did not show variation (P > 0.05). It is concluded that in situations where conventional feeds are neither readily available nor reasonably priced, cactus can be a good substitute for wheat bran as a source of energy for smallholder livestock production. [ABSTRACT FROM AUTHOR]

Sensory beef qualities could be impacted throughout the farm-to-fork continuum. The aim of this work was to predict the sensory quality classes of Longissimus muscle established from three sensory descriptors: tenderness, juiciness and flavour intensity. The extreme classes of meat quality were: Q + class including the highest scores for tenderness and juiciness, and an intermediate score for flavour intensity and Q − class including low scores for tenderness, juiciness and flavour intensity. To predict the extreme quality classes, seven decision trees were performed using the individual data related to rearing factors (p = 50), carcase traits (p = 13) and/or aged meat traits (p = 9) of 100 Charolais heifers. The decision trees established from rearing factors and carcass trait data (RF-CARCA-Tree) allowed the highest accuracy of prediction (79.7%) with 90.7% and 66.7% of correctly classified individuals, respectively. Our results showed that different combinations of factors could produce Q + class. Three rearing factors (i.e. the calculated average of concentrates' net energy content in the diet during the pasture period of pre-weaning period (PWP); the number of days concentrates were offered in calf diet during PWP; and the calculated average of concentrates' crude protein content in the fattening diet) and the conformation score could be considered as action levers to improve meat quality. These three rearing factors were related to the pre-weaning and fattening periods of the heifer, slowing a possible management of the potential beef quality from rearing factors throughout the life of the heifer. Highlights: Beef quality can be improved throughout the heifer's life by rearing factors related to concentrate in the diet. Sensory beef quality classes could be managed from rearing factors and carcass traits. Raw aged meat data did not allow to improve the prediction of sensory beef quality classes. [ABSTRACT FROM AUTHOR]

Poultry meat, particularly Peking ducks, holds a significant global market share, prized for their high meat yield and fat content. However, understanding of the molecular genetic mechanisms influencing carcass yield in ducks is limited. This research aims to use genome‐wide association analysis to uncover single‐nucleotide polymorphisms influencing carcass yield in Peking ducks, followed by identifying candidate genes linked to carcass traits. In this study, we analyzed seven traits of 643 Peking ducks at age 42 days and identified novel loci associated with these traits. A total of 35 significant loci were detected, with eight SNPs reaching genome‐wide significance. KIF20B, AGBL5, SGSM1, MRO, PLAG1, XKR4, and TGS1 were considered as important candidate genes influencing carcass yield in ducks. This study adds to the list of genes affecting Peking duck body traits, aiding marker‐assisted breeding and enhancing economic yield. [ABSTRACT FROM AUTHOR]

Objective: The improvement of carcass traits is essential for the Hanwoo industry because of the Hanwoo grade determination system, and genome-wide association study (GWAS) analysis is an instrumental tool for identifying the genetic factors that impact these traits. While GWAS analysis utilizing family data offers advantages in minimizing genetic bias, research on family-based GWAS in Hanwoo is currently lacking. Methods: This study classified Group A using both parental and offspring genetic information, and Group B based solely on offspring genetic information, to compare GWAS analysis results of Hanwoo carcass traits. Results: A total of 16 significant single nucleotide polymorphism (SNP) markers were identified in Group A, comprising 7 for carcass weight (CWT), 3 for back fat thickness (BFT), and 6 for marbling score (MS). In Group B, 7 significant SNP markers were identified, including 3 for CWT, 1 for eye muscle area, 1 for BFT, and 2 for MS. Functional annotation analysis revealed only one common function related to carcass traits between the groups, while protein-protein interaction analysis indicated more gene interactions in Group A. The reliability of estimated values for common SNP markers identified between the groups was higher in Group A. Conclusion: GWAS analysis utilizing parental genetic information holds greater potential for application, owing to its higher reliability of estimated values and the ability to explore numerous candidate genes. [ABSTRACT FROM AUTHOR]

Simple Summary: Tibetan sheep are known for their high-quality meat and strong ability to adapt, but limited information is available on the effect of dietary concentrate-to-forage ratio on carcass traits, meat quality, rumen fermentation and gut microbiota of Tibetan sheep during the cold season. Therefore, this study investigated the impact of the different concentrate-to-forage ratios on slaughter performance, meat quality, rumen fermentation, and rumen and fecal microbial community composition. The results revealed that an increase in the dietary concentrate level from 30% to 70% positively impacted slaughter performance, tenderness, and juiciness of Tibetan sheep meat. Meat color was optimized with high acceptability by consumers and was observed at a dietary concentrate-to-forage ratio of 50:50. Correlation analysis revealed a strong correlation between specific gastrointestinal bacteria and slaughter performance as well as with meat quality. These findings offer insights into the effect of the diet on slaughter performance, meat quality, rumen microbiota, and fecal microbiota of Tibetan sheep, which may inform decisions regarding feeding strategies. This study aimed to investigate the effects of different dietary concentrate-to-forage ratios on slaughter performance, meat quality, rumen fermentation, rumen microbiota and fecal microbiota in Tibetan sheep. A total of sixty male Tibetan sheep were equally allocated into three dietary groups based on concentrate-to-forage ratios, i.e., 30:70 (C30), 50:50 (C50), and 70:30 (C70). Compared with the C30 group, sheep fed the C70 diet resulted in a higher (p < 0.05) slaughter live weight (SLW), hot carcass weight (HCW), dressing percentage (DP), eye muscle area, average daily gain (ADG), and ruminal total volatile fatty acids concentration and propionate molar proportion and lower (p < 0.05) shear force and cooking loss of meat, and ruminal acetate molar proportion and acetate:propionate ratio. Sheep in the C50 group exhibited a higher (p < 0.05) SLW, HCW, ADG, and ruminal propionate molar proportion and lower (p < 0.05) shear force and cooking loss of meat, and ruminal acetate molar proportion and acetate: propionate ratio compared with the C30 group. In rumen fluid, the relative abundance of Butyrivibrio was lower (p = 0.031) in the C30 group, and that of Ruminococcus was higher (p = 0.003) in the C70 group compared with the C50 group. In feces, genus Monoglobus and UCG_002 were the most abundant in the C30 group (p < 0.05), and the relative abundance of Prevotella was significantly higher in the C70 group than in other groups (p = 0.013). Correlation analysis revealed possible links between slaughter performance and meat quality and altered microbiota composition in the rumen and feces of Tibetan sheep. Overall, feeding a C70 diet resulted in superior carcass characteristics and meat quality in Tibetan sheep, thus laying a theoretical basis for the application of short-term remote feeding during the cold season. [ABSTRACT FROM AUTHOR]

A total of 23 studies were identified in a literature search performed in the Scopus, Science Direct and Google Scholar databases for meta‐analysis. The criteria used include studies that were published from 2015 to 2023 and those reporting the effects of insect meal utilisation in poultry diets. Data on live weight (LW), carcass weight (CW), moisture, meat pH, lightness (L*), redness (a*), yellowness (b*), proximate composition (protein, fat and ash content) and shear force in broilers were subjected to OpenMEE software, and data were pooled using a random‐effect model. Subgroup analysis and meta‐regression were performed to ascertain the influence of dietary insect meals on the response of meat aspects and the source of heterogeneity, respectively, using the following moderators (insect species, dosage level, feeding duration and age at slaughter). The results indicated that dietary insect meal did not affect LW, CW, meat L*, pH, shear force, moisture, fat and ash content. In contrast, dietary insect meal increased the a* of the meat (standardised mean differences (SMDs) = 1.03; 95% confidence intervals (CIs) = 0.484–1.578; p ≤ 0.001), b* (SMD = 1.117; 95% CI = 0.334–1.90; p = 0.005), and meat protein content (SMD = 0.365; 95% CI = 0.031–0.7; p = 0.032). The subgroup analysis showed that insect meal dosage of ≤10% and age at slaughtered ≤35 days had improved the LW, CW and meat L*. In addition, the meat a*, protein and ash content were also influenced by insect species, dosage levels and age at slaughter. In conclusion, ≤10% of either Hermetia illucens or Tenebrio molitor can be included in broiler diets without compromising the LW, CW, meat pH, colour, shear force, moisture, fat and ash content in broilers. The study therefore indicated that insect meals have a bright future as an alternative protein source in poultry diets. [ABSTRACT FROM AUTHOR]

Cottonseed meal (CSM) has emerged as an alternative source of protein-based poultry feed because of the increasing cost and scarcity of soybean meal. However, it contains toxic gossypol, which restricts its use. This systematic review examines solid-state fermented CSM's impact on broiler chickens, focusing on growth performance, carcass traits, and blood parameters. To identify relevant papers, a comprehensive search of Web of Science, Scopus, and PubMed was conducted. In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology, peer-reviewed experimental articles published in English up to September 2023 were screened. A total of 60 articles were evaluated over four stages, resulting in 9 articles that met the predefined inclusion and exclusion criteria. The reduction in gossypol content was effective with bacteria like Bacillus subtilis, Aspergillus oryzae, and Aspergillus niger. The content of free gossypol in CSM is significantly reduced after solid-state fermentation using various microorganisms. Fermented CSM increased the body weight gain and feed intake of broilers, while maintaining feed efficiency, and improved growth performance. Fermented CSM included in diets positively affected carcass traits, including increased carcass weight and breast muscle development. It also resulted in decreased fat content and enhanced immune organ development. An improvement in total protein, albumin, and immunoglobulin levels was observed in blood biochemical parameters, suggesting an improved humoral immune response. Depending on the microorganisms used and their concentrations, fermented CSM also had positive effects on cholesterol, triglycerides, and LDL levels. Solid-state fermented CSM can be an effective and sustainable source of protein for broiler chickens. A future research focus should be on long-term effects, underlying mechanisms, economic feasibility, and scalability. In addition, it could be used in novel feed formulations and other livestock species to further enhance animal agriculture. [ABSTRACT FROM AUTHOR]

In this study, the effects of fully littered, slatted and their varying combinations on growth, performance, carcass and meat quality characteristics in broiler chickens were investigated. In the experiment, five treatment groups were formed as fully littered (FL), fully slatted (FS), 1/3 littered + 2/3 slatted (2/3 SF), 1/2 littered + 1/2 slatted (1/2SF), 2/3 littered + 1/3 slatted (1/3 SF). Each treatment group included 5 replicates (24 chicks in each) and a total of 600 male-female mixed fast growing broiler chicks (Ross-308) were used during 6 weeks. Weekly body weight (BW, g), feed intake (FI, g), feed conversion ratio (FCR, g.feed intake/g.weight gain), livability (%) and EPEF (European Production Efficiency Factor) were determined as performance characteristics. Carcass yield (CY, %), and the percentages of abdominal fat (AFP, %), edible internal organs (EIOP, %), gizzard (GP, %), breast (BRP, %) and thigh (TP, %) meat were the carcass characteristics. Meat quality measured by pH and color (L*: lightness, a*: redness, b*: yellowness) of breast and thigh meat, and occurrence of white striping and hemorrhaging in breast meat. The weekly BW differences among the floor treatments were significant (P < 0.01), and 1/3SF broilers were the heaviest at slaughter age (3311.6 g). The 6-week FCR in FS broilers was significantly worse than the others (1.471), but FI, livability and EPEF were similar among treatments. AFP tended to be higher in FL birds (P = 0.066), while CY, EIOP, GP, BRP and TP did not differ between groups. Breast pH was similar between treatments, with 1/2SF showing the highest (6.34) and FL the lowest (6.24) breast pH (P < 0.01). The partially slatted systems caused lighter, redder and yellower color values in breast meat (P < 0.01) than the fully littered or slatted systems, but did not change the color of the thigh meat. White striping and hemorrhaging in breast meat were not affected by the floor treatments. This study suggests that the use of partially slatted systems in broiler chickens improves meat color without compromising performance traits (body weight, feed efficiency, EPEF), litter moisture and slaughter traits and these systems could be an alternative to fully littered systems. [ABSTRACT FROM AUTHOR]

This experiment aimed to explore the effects of flavonoids in Fructus Aurantii Immaturus (FFAI) on carcass traits, meat quality, and the antioxidant capacity of finishing pigs. The results indicated that the addition of an appropriate amount of FFAI into their diet could significantly reduce the backfat thickness and perirenal fat percentage of finishing pigs, as well as the drip loss, water-holding capacity, shear force, and the levels of lactate, glucose-6-phosphate, glucose, ATP, phosphofructokinase, and pyruvate in the longissimus dorsi (LD) muscle. It also elevated the levels of flavor amino acids such as glutamate, serine, and threonine, and enriched the composition of flavor substances, including benzene and octanal, which significantly contributed to the enhancement of pork flavor. Furthermore, it enhanced the expression levels of MyHC I and MyHC IIa. In summary, the appropriate addition of FFAI to the diet could improve the carcass traits, meat quality, and antioxidant capacity of finishing pigs. The optimal level of FFAI supplementation is 0.12%. [ABSTRACT FROM AUTHOR]

The study aimed to determine the effect of dietary supplementation with leaves of industrial hemp (Cannabis sativa L.) on live weight, carcass (carcass weight, dressing percentage, individual cuts and giblets) and meat quality (pH, color, EZ-DripLoss, thawing loss, cooking loss, and shear force) traits of broiler chicken meat. The study was conducted on 100 male Ross 308 chickens, which were divided into 4 experimental groups. The control group (K-0) was fed without hemp leaves, while groups P-1, P-2 and P-3 were fed with the addition of 1%, 2%, and 3% industrial hemp leaves, respectively. The animals were slaughtered at 42 days of age. Group P-2 had the highest wing proportion (10.30%), which was significantly different from the group P-1 (9.43%; P = 0.004). Abdominal fat was significantly lower in groups P-2 (0.66%) and P-3 (0.59%) compared to group P-1 (1.06%; P = 0.004). The breast meat of group P-2 was the lightest (L* = 48.28) and differed significantly from that of group P-1 (L* = 46.24; P = 0.044). Group P-1 had the highest shear force value (17.22 N), which was significantly different from groups P-2 (P = 0.0047) and P-3 (P = 0.0506). Hemp leaves may improve the quality of broiler meat, but more research is needed to understand their full effect on other traits and health.

Information on the genetic architecture of the production traits of indigenous African chicken is limited. We performed a genome-wide association study using imputed Affymetrix Axiom® 600K SNP-chip genotypes on 1,113 chickens from three agroecological zones of Ghana. After quality control, a total of 382,240 SNPs remained. Variance components and heritabilities for some growth, carcass and internal organ traits were estimated. The genetic and phenotypic correlations among these traits were also estimated. The estimated heritabilities of body weight at week 22 (BW22), average daily gain (ADG), dressed weight, breast weight, thigh weight, wing weight, drumstick weight, and neck weight were high and ranged from 0.50 to 0.69. Estimates of heritabilities for head weight, shank weight, and gizzard weight were moderate (0.31-0.35) while those of liver weight, back weight, dressing percentage, and heart weight were low (0.13-0.21). The estimated heritabilities of dressed weight, breast weight, wing weight, drumstick weight, neck weight, shank weight, and gizzard weight, corrected for BW22, were moderate (0.29-0.38), while the remaining traits had low heritability estimates (0.13-0.21). A total of 58 1-Mb SNP windows on chromosomes 1, 2, 4, 5, 6, 7, 8, 9, 13, 18, and 33 each explained more than 1% of the genetic variance for at least one of these traits. These genomic regions contained many genes previously reported to have effects on growth, carcass, and internal organ traits of chickens, including EMX2, CALCUL1, ACVR1B, CACNB1, RB1, MLNR, FOXO1, NCARPG, LCORL, LAP3, LDB2, KPNA3, and CAB39L. The moderate to high heritability estimates and high positive genetic correlations suggest that BW22, ADG, dressed weight, breast weight, thigh weight, wing weight, drumstick weight, and neck weight could be improved through selective breeding.

The present experiment studied the effects of egg composition (egg yolk content; Y) of two different chicken genotypes (selected by computed tomography; CT) on hatched chick growth performance, slaughter traits, and meat quality. Three thousand five hundred eggs per genotype were scanned by CT. Then, for each genotype, eggs were selected according to their Y content: low (21.0 ± 0.88 - 350 eggs), medium (24.5 ± 0.15- 350 eggs) and high (28.3 ± 0.98 - 350 eggs). The remaining eggs were excluded from the study. At 11 weeks of age, 15 chickens per group were slaughtered, carcasses were dissected and breast and legs were excised and dedicated to meat quality evaluations. Many parameters were influenced in the meat-type (EE) chickens, including slaughter, breast and leg weights, and abdominal fat content, whereas only the breast incidence on slaughter weight was affected in Tetra-H hybrid. In neither genotype were the meat traits affected by Y content. Two exceptions were represented by leg thawing loss, higher in low Y group compared to medium and high Y group, and by tibia length, longer in high Y content group than in the medium one, both for EE chickens. Similar findings were observed for the meat fatty acid (FA) profile, as only some single FA were influenced by Y content, however, apparently without a specific physiological meaning. The present work demonstrated that the Y content, measured by CT, allowed to select high-quality meat-type animals characterised by the best productive performances in terms of growth rate, live weight, slaughter weight, breast and thigh weights, and with lower abdominal fat content. These findings would bring positive advantages to hatcheries in terms of chick quality and also to farmers in terms of economic revenues: They would rear robust animals that would guarantee a higher probability of survival in the first rearing period and would be characterised by a high slaughter weight at the end of the productive cycle.

Background and Aim: The creation of objective methods for the evaluation and improvement of quantitative and qualitative indicators of meat productivity in farm animals should be based on a comprehensive analysis of the genetic, physiological, and biochemical parameters of the animal. This study aimed to investigate the effects of growth hormone (GH) and thyroglobulin (TG5) gene polymorphisms on the hormonal status, slaughter traits, and chemical, amino acid, and fatty acid composition of meat in Hereford bulls. Materials and Methods: Hereford bulls (n = 9) were reared under the same feeding and housing conditions until the age of 21 months, after which they were slaughtered. Polymerase chain reaction-restriction fragment length polymorphism was performed for genotyping GH L127V and TG5 C422T polymorphisms. The experimental animals were evaluated to determine slaughter traits (including pre-slaughter weight, carcass, and internal fat weight and yield), chemical, fatty acid, and amino acid composition of ground beef, and hormonal status using serum concentrations of GH, triiodothyronine, and thyroxine. Results: Animals with the valine homozygous (VV) genotype of GH had the maximum serum GH level of 9.33 mIU/mL (p = 0.10) higher than leucine homozygous (LL) genotype carriers. Individuals with the LL genotype outperformed V-allele carriers in serum thyroxine (T4) concentration by 21.3–30.5 nmol/L (16.15%–24.86%; p < 0.01–0.05). Genetic differentiation induced by TG5 C422T polymorphism was determined to a lesser extent by the hormonal status of the Hereford animals. The V-allele was associated with increased carcass weight, with VV homozygotes significantly outperforming LL individuals by 45.0 kg (13.61%; p < 0.05). The T allele at the TG5 gene polymorphism was associated with more intense lipogenesis and less protein synthesis in muscle tissue and these effects were enhanced in the homozygous state. Young animals with the TT variant of the TG5 gene exhibited a significantly superior polyunsaturated fatty acid/saturated fatty acid ratio of 0.012 units (p < 0.01). Carriers of the LL genotype were characterized by minimum amino acid content in muscle tissue. Heterozygous bulls exceeded LL homozygotes in the sum of essential amino acids by 3.09% (p = 0.10) and non-essential amino acids by 1.9% (p < 0.05). Conclusion: The development of breeding programs for the Hereford breed should be carried out considering genetic features that determine the formation of economic traits in animals. Analysis of polymorphisms in the TG5 gene is a promising method for the early diagnosis of the fatty acid composition of beef. Identification of polymorphisms in the GH gene allows the prediction of higher productivity potential and amino acid composition of meat. The different effects of the GH and TG5 genes on the development of various economic traits allowed us to determine further vectors for scientific research on their complex associations in Hereford cattle, which will be useful for planning effective breeding schemes.

Background: A typical broiler production program includes three feeding phases: Pre-starter (from day 1 to 10), Starter (11-21 days), and Grower (from day 22 to slaughter). The program should allow the bird to express its genetic potential and respond to the nutritional challenges. Objective: To determine the effect of duration of the starter and grower phases on growth performance parameters (feed intake and feed conversion), mortality, skin pigmentation, and carcass yield in broiler chickens. Methods: A total of 1,500 Ross 308 AP male broilers were randomly assigned to five feeding programs with different duration, feed presentation (pellet vs. crumble), and anticoccidial (narasin + nicarbazin vs. salynomicin). The variables evaluated were growth performance (body weight, feed intake, and feed conversion), carcass (weight and yield), breast weight and yield, and skin pigmentation. Statistical evaluations were conducted on d 28 and 40 of age. Results: On d 28 of age, differences (p<0.05) were observed for body weight and feed conversion, but not for feed intake. T4 and T5 resulted in the best weight and feed conversion. Differences (p<0.05) were recorded on d 40 for body weight, with higher values in T4 and T5 compared to T1. Carcass weight differed between T1 and T4 (p<0.05), without difference for carcass or breast performance. The statistical analyses of carcass pigmentation showed an effect on redness ("a") and yellowness ("b") at d 28. Conclusions: Body weight and feed conversion of broilers from d 22 to 28 improve by extending the starter phase one week, using pelleted feed added with an ionophore anticoccidial. Skin pigmentation of broilers at slaughter is not affected by restricting pigment intake for one week. [ABSTRACT FROM AUTHOR]

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Feed additive antibiotics have been used for many decades as growth promotors or antibacterial substances worldwide. However, the adverse impacts of using antibiotics in animal or poultry feeds are not widely recognized. Therefore, the search for alternatives, such as probiotics, prebiotics, phytobiotics, post-biotics, bacteriophages, enzymes, essential oils, or organic acids (OAs), has become urgent. OAs are produced by beneficial intestinal bacteria through the fermentation of carbohydrates. OAs and their salts are still used as feed preservatives. They have long been added to feed in order to minimize contamination and the growth of harmful bacteria and fungi, reduce deterioration, and prolong the shelf life of feed commodities. Moreover, they have been mostly added to poultry feed as a blend to obtain maximal beneficial effects. The supplementation of poultry with OAs could improve the growth performance parameters and carcass traits, promote the utilization of nutrients, boost the immune response, and inhibit the growth of pathogenic bacteria. Therefore, this review article provides valuable insights into the potential benefits of using OAs in reducing microbial load, enhancing performance parameters in broilers and layers, improving gut health, and boosting the immune response. [ABSTRACT FROM AUTHOR]

Introduction: Aflatoxin B1 is the most dangerous form of aflatoxins that could be produced by Aspergillus flavus and Aspergillus parasiticus molds. Contamination of feedstuffs with aflatoxins is problematic during the manufacturing, processing, storage, and transportation stages, and it has adverse effects on the health and productivity of poultry and human health. By using inorganic and organic toxin binders in poultry feed, aflatoxins are not allowed to be absorbed through the animal's digestive system, and it is considered a good solution to reduce their negative effects. Materials and Methods: In this research, the effects of adding a multi-component toxin binder to diets containing aflatoxin B1 were investigated on growth performance, carcass traits, and immune parameters of broilers, by using 180 one-day-old male broilers (Ross 308) in a 3×3 factorial arrangement in a completely randomized design with three levels of toxin binder (0.0, 0.5, and 1.0 kg/ton) and three levels of aflatoxin B1 (0.0, 0.5, and 1.0 mg/kg) in nine treatments, four replications, and five chickens in each replicate. Results and Discussion: The results showed that the using of 1.0 kg/ton of toxin binder significantly reduced the negative effects of 0.5 mg/kg of aflatoxin B1 on the average daily feed intake and weight gain in the finisher and entire production periods and the final live weight in whole production period (P<0.05). The regression equations (Y= -25.033x+ 65.734) with (R²= 0.97), (Y= -23.961x+ 64.844) with (R²= 0.91), and (Y= -15.133x+ 64.319) with (R²= 0.75) were obtained to predict the average daily weight gain of birds fed with treatments containing 0.0, 0.5, and 1.0 kg/ton of "Delta bond®" toxin binder and different levels of aflatoxin B1, respectively. Feeding chickens with diets containing aflatoxin B1 significantly increased liver and spleen weights (P<0.05). All treatments containing 1.0 mg/kg of aflatoxin B1 and treatments containing 0.5 mg/kg of aflatoxin B1 and 0.0 and 0.5 kg/ton of toxin binder showed a significant decrease in the bursa of Fabricius weight compared to the other treatments (P<0.05). In addition, the treatment containing 1.0 mg/kg of aflatoxin B1 without a toxin binder increased heart weight compared to the other treatments (P<0.05). In the case of immune parameters, the amount of heterophils and the ratio of heterophils to lymphocytes were significantly increased and the number of lymphocytes was significantly decreased as the aflatoxin B1 level increased (P<0.05). Furthermore, there were no significant effects for the main and interaction of aflatoxin B1 and the toxin binder for the Newcastle antibody titer. Conclusion: Based on the results, the addition of 1.0 kg/ton of a multi-component toxin binder to diets containing 0.5 mg/kg aflatoxin B1 can improve the average daily feed intake and weight gain in the finisher and entire production periods, final live weight, and bursa of Fabricius weight of broilers. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the impact of dietary zinc (Zn) and selenium (Se) supplementation on the growth, blood parameters, antioxidant levels, immune response, and carcass traits of rabbits under summer heat stress in Egypt. Thirty male New Zealand White rabbits, aged 35 days with an average weight of 637.96 ± 15.70 g, were divided into three groups: a control group, a zinc-supplemented group (50.0 mg/kg diet), and a selenium-supplemented group (0.3 mg/kg diet). The results revealed that Zn supplementation led to significant improvements in feed intake, body weight, and feed conversion ratio compared to Se supplementation and the control. Both Zn and Se supplementation increased serum total protein, albumin, superoxide dismutase (SOD), glutathione peroxidase (GPx), lysozyme, and immunoglobulin A (IgA), while decreasing total cholesterol, triglycerides, low-density lipoprotein (LDL), very low-density lipoprotein (VLDL), urea, creatinine, and MDA. However, no significant differences were observed in all hematological parameters, blood contents of high-density lipoprotein (HDL), alanine aminotransferase (ALT), aspartate aminotransferase (AST), or immunoglobulin G (IgG), as well as carcass traits among the experimental groups. In conclusion, supplementing rabbit diets with Se (0.3 mg/kg diet) or Zn (50 mg/kg diet) could ameliorate the adverse effects of heat stress on rabbit growth and health in hot climates of the summer season in Egypt. [ABSTRACT FROM AUTHOR]

This study investigated the impact of heat stress on growth and carcass traits in four poultry genotypes—Giriraja, Country chicken, Naked Neck and Kadaknath reared in a hot and humid tropical environment. Birds from all genotypes had ad libitum access to feed and water while being challenged with consistently high environmental temperatures in the experimental shed. Daily diurnal meteorological data were recorded inside and outside the shed. The study specifically examined growth variables and carcass characteristics. Significant differences (p < 0.01) were observed in body weight and average daily gain at various intervals. Notably, feed intake showed significant differences (p < 0.01) across weeks, indicating interactions between genotypes and time intervals. The feed conversion ratio (FCR) varied significantly (p < 0.01), with the highest FCR recorded in the Kadaknath breed. Livability percentages were similar across groups, except for Giriraja, which had significantly lower livability (p < 0.01). Carcass traits, including dressing, wings, feathers and giblet percentages, showed significant differences among genotypes (p < 0.01). Hepatic mRNA expression of growth‐related genes revealed numerical variations, with Naked Neck displaying the highest (p < 0.05) fold change in IGF‐1 expression compared to other genotypes. The study recognized in the Naked Neck genotype to possess higher resilience in maintaining homoeostasis and uncompromised growth under heat stress, providing valuable insights for sustainable poultry farming in challenging environmental conditions. [ABSTRACT FROM AUTHOR]

Background: Poultry production quality could be adjusted or improved through the introduction of local plant resources into the diet. The current study evaluated the effects of total corn substitution with triticale and bentonite supplementation on broiler performance, carcass meat characteristics and blood profiles. Methods: Ninety one-day old broiler Cobb 500 chicks were allocated in a completely randomized experimental design, with three dietary treatments totaling 30 birds per treatment. The treatments contained either corn as a control group (BD), triticale (TRT) as a sole grain source, or triticale + 2% bentonite (TRT2%). The diets were provided from 14 to 47 days of age. Growth performance, carcass and breast meat quality and serum components were measured. Result: The chicks fed a triticale-based diet (TRT2%) had a higher final body weight and weight gain (P<0.05), while the FCR increased in the birds fed a triticale-bentonite-based diet (TRT2%). The data obtained indicated that total replacement of triticale for corn and dietary supplementation with bentonite resulted in better growth performance and an increase in breast yield (P<0.05). Moreover, the dietary supplementation of bentonite and triticale had a significant influence (P< 0.05) on the serum levels of triglycerides and calcium. The chicks fed a basal diet had significantly (P<0.05) higher triglycerides and lower calcium blood serum levels than those fed experimental diets. However, there was no significant effect on breast meat traits (P>0.05). [ABSTRACT FROM AUTHOR]

The purpose of the experiment was to determine the effect of the addition of dried ground whole leaves of the herb Salvia officinalis L in the feed for fattening rabbits, on the productive parameters, some blood indicators and carcass characteristics. The inclusion of ground dry leaves of the herb sage in feed for fattening rabbits has a positive effect on productive performance. In the experimental group were improved average daily gain by 29,2% (P<0,05), feed conversion ratio by 19% (P<0,05) for the entire experimental period and average daily feed consumption by 3,8% (P<0,05) during the first week of the experiment compared to the control.The tested additive did not reliably affect the parameters of the slaughter analysis, the chemical analysis of the meat and blood parameters. [ABSTRACT FROM AUTHOR]

The growing animal welfare concerns regarding poultry production have led to the rearing of slow-growing meat type chickens also known as free-range chickens. In Zimbabwe these slow-growing chickens are gaining popularity as an alternative to the commercial broiler chickens owing to their preferred sensory attributes comparatively. Little is known regarding the quality of the meat versus that of the conventional broilers. We evaluated the physical characteristics and nutritional composition of meat from dual purpose slow-growing hybrids, Sasso C431 and TR51 in comparison with the commercial broiler breed Ross 308, under intensive feeding conditions. Birds were fed the standard commercial chicken feed produced by Hamara, a local chicken and chicken feed producing company. Birds were slaughtered on days 42, 56 and 70 of life where carcass and breast yield were measured. The pH, drip loss and cooking losses were determined for all carcasses. Proximate composition (dry matter, ash, protein, fat, carbohydrate) and mineral composition (iron, zinc and phosphorus) were determined for all the meat samples. The fast-growing broiler breed had a higher breast yield; than the slower-growing breeds, Sasso C431 and TR51 breeds (P<0.05). The highest cooking and drip loss were observed in the faster growing breed Ross 308 and the lowest ones for Sasso C431 and TR51 breeds (P<0.05). Shear texture values were higher in the Sasso C431 and TR51 than the Ross 308 breed (P<0.05). The Sasso C431 and TR51 breeds can produce more meat with a lower fat and a higher protein compared to the Ross breeds. [ABSTRACT FROM AUTHOR]

Simple Summary: This study explored the effects of age, sex, and muscle type on post-mortem muscle acidification in Botucatu rabbits, addressing the gap between recommended meat quality assessment standards and industry practices. The World Rabbit Science Association (WRSA) suggests chilling carcasses for 24 h at 0–4 °C, while Brazilian practices often involve immediate freezing at temperatures below −18 °C. This study aimed to clarify how these practices affect muscle pH and rigor mortis development. Eighty Botucatu rabbits were categorized into young females and males, does, and bucks. Carcasses were chilled for 24 h at 4 °C. pH and temperature measurements were taken hourly for 24 h post-mortem in the Longissimus lumborum (LL) and Biceps femoris (BF) muscles. Rigor mortis was assessed manually alongside pH measurements. Botucatu does were heavier, with a less marked initial pH drop in the LL and delayed stabilization at 6 h post-mortem. Muscle acidification was more pronounced in the LL than in the BF. Rigor mortis set in at 5 h for young rabbits and bucks, and 6 h for does, resolving by 18 h. Thus, chilling rabbit carcasses for at least 18 h at 4 °C aligns WRSA guidelines with industry needs, ensuring effective rigor mortis and muscle-to-meat transformation. The aim of the present study was to evaluate the characteristics of carcasses, monitor their pH evolution during the first 24 h post-mortem, and determine the time required for the establishment and resolution of rigor mortis in different categories of Botucatu rabbits. Live weight at slaughter, carcass weight, and yield were higher in 12-month-old animals compared to 3-month-old rabbits, regardless of sex. There was an effect of muscle type, age, and sex on the kinetics of muscle acidification, with the Biceps femoris showing a significantly higher pH than the Longissimus lumborum from 4 h post-mortem onward. The establishment of rigor mortis occurred at 5 h post-mortem in young rabbits and bucks and at 6 h post-mortem in does, along with pH stabilization, while the resolution of rigor occurred at 18 h post-mortem for all types of carcasses evaluated. In conclusion, Botucatu rabbit carcasses should be chilled continuously at 4 °C for a minimum of 18 h to ensure efficient rigor mortis progression and muscle-to-meat transformation throughout the carcass. [ABSTRACT FROM AUTHOR]

Culling of guinea pigs can provide a large number of animals per year for meat production, but little information is available in the scientific literature on the carcass characteristics and non-carcass components of these animals. The objective of this study was to evaluate the carcass and non-carcass characteristics of cull guinea pigs in comparison to their fattening counterparts. Forty-eight fattening (3 months-age, 24 females and 24 males) and forty-eight cull (14 months-age, 24 females and 24 males) guinea pigs were slaughtered and carcass yield, linear measurements, tissular composition, and non-carcass components were evaluated. In general, cull guinea pigs had higher carcass, tissue, and non-carcass component weights. Cull male and both female guinea pig groups had similar carcass yields. Cull animals had higher carcass and hind leg lengths, lumbar and thoracic circumferences, and carcass compactness than their young counterparts. However, a sex effect was found for leg compactness depending on whether they were fattened or cull. Tissue percentages values were similar between fattening and culling animals of the same sex. However, females had a higher percentage of fat tissue than males. Fattening females had the best muscle to bone ratio, followed by cull males. The non-carcass elements were more represented in fattening animals than in culls, probably due to an allometric growth of the viscera in relation to the rest of the body. In commercial and cooking terms, this information is valuable for producers and researchers who need to understand the factors that influence carcass characteristics of guinea pigs. [ABSTRACT FROM AUTHOR]

The present experiment studied the effects of egg composition (egg yolk content; Y) of two different chicken genotypes (selected by computed tomography; CT) on hatched chick growth performance, slaughter traits, and meat quality. Three thousand five hundred eggs per genotype were scanned by CT. Then, for each genotype, eggs were selected according to their Y content: low (21.0 ± 0.88 - 350 eggs), medium (24.5 ± 0.15- 350 eggs) and high (28.3 ± 0.98 - 350 eggs). The remaining eggs were excluded from the study. At 11 weeks of age, 15 chickens per group were slaughtered, carcasses were dissected and breast and legs were excised and dedicated to meat quality evaluations. Many parameters were influenced in the meat-type (EE) chickens, including slaughter, breast and leg weights, and abdominal fat content, whereas only the breast incidence on slaughter weight was affected in Tetra-H hybrid. In neither genotype were the meat traits affected by Y content. Two exceptions were represented by leg thawing loss, higher in low Y group compared to medium and high Y group, and by tibia length, longer in high Y content group than in the medium one, both for EE chickens. Similar findings were observed for the meat fatty acid (FA) profile, as only some single FA were influenced by Y content, however, apparently without a specific physiological meaning. The present work demonstrated that the Y content, measured by CT, allowed to select high-quality meat-type animals characterised by the best productive performances in terms of growth rate, live weight, slaughter weight, breast and thigh weights, and with lower abdominal fat content. These findings would bring positive advantages to hatcheries in terms of chick quality and also to farmers in terms of economic revenues: They would rear robust animals that would guarantee a higher probability of survival in the first rearing period and would be characterised by a high slaughter weight at the end of the productive cycle. [ABSTRACT FROM AUTHOR]

The impacts of cumulative Chlorella vulgaris intake (proportion of microalga in the diet multiplied by the total feed consumed by each bird) on broiler carcass traits, meat quality and oxidative stability were reviewed to identify the optimal intake levels for maximising benefits. Our findings indicate that a cumulative intake of 8.73 g/bird significantly enhances thigh yield, while levels ranging from 8.73 to 401 g/bird optimise carcass weight and overall meat quality. However, higher cumulative levels may reduce carcass dressing percentage due to metabolic inefficiencies. Furthermore, C. vulgaris intake improves the oxidative stability of broiler meat by increasing antioxidant levels and balancing pro- and antioxidants. Including C. vulgaris in broiler diets boosts total carotenoid content, and antioxidant assays confirm that it enhances meat oxidative stability, with low to moderate cumulative intake levels (8.73 to 401 g/bird) providing the best balance of benefits. Optimal oxidative stability and antioxidant properties were observed at a cumulative intake level of 401 g/bird, showing significant improvements in meat antioxidant capacity. Higher levels may lead to diminishing returns or potential negative effects due to the digestibility issues of the microalga. Future research should refine intake models, understand the bioavailability of C. vulgaris nutrients and explore cost-effective methods to enhance its digestibility, to ensure its viability and sustainability as a feed additive. [ABSTRACT FROM AUTHOR]

Context: Traditional smallholder pig farming plays an important role in farmers' income and national food security in the low- and middle-income countries in Southeast Asia including Laos; however, its productivity is low and it is often environmentally unsustainable. Aims: The objectives of this study were to evaluate the effects of using fermented bed-floor housing compared with the conventional concrete-floor housing on growth, carcass treats and economic return on raising Laos native pigs. Methods: The study was conducted at the Faculty of Agriculture, National University of Laos. Twenty four castrated native pigs, aged ±3 months with initial liveweight of 17 ± 2 kg/head, were randomly assigned to the following housing types as treatments: (1) conventional concrete-floor system (CS) as control, and (2) fermented bed-flooring system (FB). The pigs were fed with similar diet with 16.01% crude protein and 11,796 kJ/kg gross energy for a period of 84 days after a 14-day adaptation to the feed. Each treatment was replicated four times (pens), with three pigs/pen. Data on feed intake, liveweight change, carcass trait and costs and returns of production in the two treatments were analysed using Student's paired-sample t -test. Key results: Pigs kept in FB flooring had higher DM and nutrient (crude protein, crude fibre, ether extract and organic matter) intakes than did their counterparts raised in the CS, but the differences were not significant when adjusted to bodyweight basis. There were also no significant differences in growth performance (average daily gain (ADG) and feed conversion ratio (FCR)), and carcass traits, except that pigs from FB had higher hot carcass weight, dressing percentage and rib and bone weights. Native pigs kept in the FB system had significantly higher total production costs because of the cost of the bedding material, but also had four-fold higher net income return generated from the sale of the fermented floor compost. Conclusions: Fermented bed-flooring system has no significant impact on growth and key carcass traits, but significantly enhanced profit. Implications: Fermented bed-flooring system should be promoted for rearing local pigs under smallholder farms to increase profit and protect the environment in the low- and middle-income countries. Traditional indigenous pig farming using concrete floor has low productivity and is environmentally unsustainable. Fermented bed-flooring system enhances net profit by four fold through sale of the flooring compost. Fermented bed floor provides a profitable and environmentally sustainable option for smallholder pig farming in the developing countries. This article belongs to the Collection Sustainable Animal Agriculture for Developing Countries 2023. [ABSTRACT FROM AUTHOR]

Background: Ningxiang pigs are known for tasty meat and high intramuscular fat content. Currently, the slow growth rate and low lean meat rate of Ningxiang pigs have greatly restricted the development of its market. Therefore, the objective of this study is to explore the changes in carcass traits, meat quality, visceral organ weight indices, bones and muscles development with slaughter ages of Ningxiang pigs. Methods: The experiment used 0, 60, 120, 180, 240, 300 and 360 days old Ningxiang pigs as the research objects, and 6 castrated male pigs in each group were randomly selected. The carcass traits, meat quality, visceral organs weights and skeletal muscle weights were measured. The correlation between carcass traits and meat quality were analyzed by bivariate analysis, and the regression equations between slaughter ages and these indicators were established. Result: The results showed that pre-slaughter weight and weights of carcass, head, feet, skeleton and muscle, loin eye area, cooking yield, marbling and the large intestine weight index at 0 d, backfat thickness at 60 d, fat percentages at 60 and 120 d and the lean meat percentage at 240 d, redness at 120 d of Ningxiang pigs were lowest, the heart, lung, kidney and small intestine weight percentages were highest at 0 d (P<0.05). Carcass traits and meat quality had different significant correlation at different slaughter ages. So the indices of carcass, meat quality, bones and muscles of Ningxiang pigs changed with slaughter ages. In general, the overall performance of 300 d Ningxiang pigs is better. [ABSTRACT FROM AUTHOR]

Introduction: At the last days of incubation, avian mortality commonly happens due to the lack of enough nutrients and amino acids (Fardoost et al. 2019). However, in ovo injection or in ovo feeding is considered a new technique for improving growth of chickens (Ebrahimi et al. 2017). Most studies indicated improving effect of in ovo feeding of nutrients (especially amino acids) on small intestine growth and histology as well as higher absorptive capacity of digestive system (Ebrahimi et al. 2017, 2018a,b; Elwan et al. 2019; Fardoost et al. 2019). Previous studies indicated an improving effect of excess feeding of arginine on growth performance, carcass traits, blood metabolites, and intestinal histology of broilers (Ebrahimi et al. 2013, 2014, 2016b). However, there are few records regarding the impact of in ovo injection of arginine on intestine histology of chickens. Accordingly, the present study was designed to evaluate the effect of in ovo injection of different levels of arginine on carcass traits, blood metabolites, and small intestine histology of broiler chickens. Materials and methods: For this reason, 300 fertile broiler breeder eggs were divided into three treatment groups: 1- 0.5% L-arginine in ovo injection group (100 eggs), 2- 1% L-arginine in ovo injection group (100 eggs), 3- control group included distilled water injected (sham-control subgroup, 50 eggs) and non-injected (control subgroup, 50 eggs). Eggs were then set into the incubator for the first 18 days with the temperature of 37.8°C and six rotations per day. At d 14 of incubation, eggs were injected into the amniotic fluid (Ebrahimi et al. 2017) as follows: 1- in ovo injection of 5 mg Larginine/ ml distilled water, 2- in ovo injection of 10 mg of L-arginine/ml distilled water, 3- control group included sham-control (in ovo injection of 1 ml distilled water) and control (received no injection). For in ovo injection, solution pH was set at 7.0. At d 18 of incubation, eggs were moved into hatchery boxes. After hatching, chicks were reared for 24 days. During the experiment, chicks received standard commercial diets based on Ross recommendations asstarter (0-10 days) and grower (11-24 days), (Table 1). At d 24, blood samples of three chickens per each replicate were collected, centrifuged (3000 rpm for 20 minutes), and serum was separated to evaluate cholesterol, glucose, triglyceride, uric acid, and total protein by the Enzymatic Colorimetric method (Ebrahimi et al. 2017). Then, all birds were weighed, slaughtered, some carcass traits (scalped carcass, eviscerated carcass, breast, thigh, gizzard, proventriculus, pancreas liver without gall bladder, heart, duodenum, jejunum, and ileum were weighed, and their relative weight to chicken body weight were calculated. Also, length of duodenum, jejunum, and ileum was evaluated and their samples were stored in 10% formalin for fixation to evaluate histological parameters (crypt depth, villus height, villus thickness, mucosal thickness, and crypt diameter) using Hematoxylin - Eosin staining method (Ebrahimi et al. 2017). Then, villus height to crypt depth ratios were calculated. Afterwards, data were analyzed based on a completely randomized design by the Proc GLM of SAS software (Ver 9.2). Also, TukeyKramer test was used for comparing treatments and results presented as least square means ± standard error. Results and discussion: Based on the results, in ovo injection of different levels of L-arginine did not affect hatchability, day-old chick weight, chick weight to egg weight ratio, 24-day-old chicken weight, feed conversion ratio, relative weight of all carcass traits, cholesterol, glucose, total protein and blood urea nitrogen (P> 0.05), (Table 2). However, serum triglyceride was significantly affected by experimental treatments (P <0.01) and the highest amount was observed in 0.5% L-arginine in ovo injection group (Table 2). In a similar study, Gao et al. (2017) indicated that L- arginine in ovo injection increased weight gain of broiler chickens. Furthermore, Abdolalizadeh Alvanegh et al. (2017) reported the improving effect of in ovo injection of different ratios of L- arginine to L- lysine on chick weight and their carcass traits. Also, they reported higher serum total protein level, while lower blood urea nitrogen of broiler chicks with in ovo injection of different ratios of L- arginine to L- lysine (Abdolalizadeh Alvanegh et al., 2017). Present results indicated no significant effect of in ovo injection of L-arginine on most weight and length parameters of small intestine length (P>0.05); however, relative weight of jejunum was significantly affected by in ovo injection of L-arginine (P<0.05) and the highest amount was observed in 0.5% L-arginine in ovo injection group (Table 3). Present results indicated no significant effect of in ovo injection of L-arginine on duodenal crypt diameter; jejunal villus height, crypt depth and diameter, and mucosal thickness; and ileum villus height, crypt depth, villus height/crypt depth ratio, and mucosal thickness (P>0.05), (Table 3). However, significant effect of in ovo injection of Larginine was observed on duodenal villus height, villus thickness, crypt depth, villus height/crypt depth ratio, and mucosal thickness; jejunal villus thickness and villus height/crypt depth ratio; and ilium villus thickness and crypt diameter (P<0.05), (Table 3). Also, the highest amount in most histological parameters was observed in 1% arginine treatment (Table 3). In a similar study, it was reported that in ovo injection of L- methionine had a positive impact on small intestine length and weight with improvement in villus height, crypt diameter, crypt depth, and villus height/crypt depth ratio of duodenum and jejunum (Fardoost et al. 2019). Also, in ovo injections of L- lysine improved histological parameters of duodenum, jejunum, and ileum (Ebrahimi et al. 2017). Ebrahimi et al. (2018b) with in ovo injection of different DL- methionine to L- lysine ratios reported higher small intestinal weight and length along with higher Villus height and Villus height to crypt depth ratio. Conclusion: Based on the overall results of the study, injection of 0.5% arginine showed a positive effect on the growth and small intestine morphology of broiler chickens. [ABSTRACT FROM AUTHOR]

This study investigated the carcass traits, physicochemical characteristics, fatty acid profile and protein profile of male Khiew-Phalee native (KP), Pradu Hang Dam (PHD), and commercial broiler chickens (CBR). All samples were collected from farms in Uttaradit province and determined the carcass traits and physicochemical characteristics, including proximate composition, pH, meat color, shear force, drip loss, cooking loss, and also analyzed the fatty acid profile, purine content, and protein profile. The results showed that carcass traits such as live weight, carcass weight, and cutting percentage showed a highly significant decrease (p

Meat rabbits are a small herbivorous livestock and have been popularly raised in China for producing high-quality meat. Therefore, it is economically important to genetically improve both carcass performance and meat quality in meat rabbits. However, we still know less about the underlying candidate genes that may determine phenotypic variation on carcass and meat traits of meat rabbits. The main objective of this study was to identify candidate genes whose mRNA expression levels may be significantly involved in regulating carcass and meat traits of meat rabbits based on the transcriptome-wide association studies (TWAS). Five carcass traits of the carcass weight (CW), dressing out percentage (DP), cut weight of hind legs (LW), weight ratio of cut hind legs to carcass (RLW), and weight of visceral and interscapular fat (WF), as well as two meat traits of the drip loss (DL) and cooking loss (CL) were phenotyped in a F1 crossbred population (N = 119) between Zika rabbits and Sichuan White rabbits. The effects of mRNA expression levels of a total of 10,288 genome-wide genes on these seven traits were statistically estimated using the mixed linear model, in which the polygenic background effects were accounted for. Our results revealed two candidate genes (RDH5 and MTARC2) that were statistically significantly associated with LW trait (the adjusted p values

We hypothesized that transportation might impact beef sensory quality, particularly as the distance between farms and the slaughterhouse increases. Specifically, we expected that pre-slaughter transport over longer distances would induce stress in the cattle, resulting in elevated ultimate pH and, consequently, reduced beef quality. Thus, this study aimed to specifically study the effects of transport in commercial conditions of Limousin cows from farms located in different areas of France to slaughter on ultimate pH (pHu) measured in the Longissimus thoracis muscle (LT), marbling (two major factors affecting eating quality) and the MSA Index (a global indicator of potential eating quality at the carcass level). Cattle were studied according to distance (

The leaves of Rumex nervosus (RNL) have beneficial effects associated with phytochemical products, such as gallic acid (GA), and could therefore have a positive effect on breast quality traits in broilers. This study aimed to assess the potential effects of supplementation with RNL as a natural herb on breast quality, carcass characteristics, and production indices of broilers. A total of 120 broiler chicks were arbitrarily assigned to four dietary treatment groups, each with five replicates (♂:♀ = 3:3 per replicate). Each experimental meal was designed to contain a basal diet with 0 g RNL (CONT), 1 g RNL (T1), 3 g RNL (T2), and 5 g RNL (T3). During the study, production parameters were collected for each replicate. On day 34, one male broiler from each replicate was slaughtered for breast meat quality parameters. The present findings revealed that broilers treated with T2 had a larger absolute carcass weight (g) and dressing yield (%) (P

The importance of using agro-industrial by-products in feeding livestock is important in terms of preserve the environment and conversely, reducing the cost of feeding and production. Therefore, the purpose of this study was to assess how feeding jojoba meal (JOJ) affected growth performance, cost of production, and carcass features of growing lambs. Twenty-four Awassi lambs weighing 16.4 kg ± 0.17 kg were randomly selected and given two diets; a control diet without the inclusion of JOJ (CON), and JOJ100 with the presence of 100 g/kg dry matter (DM) of JOJ. The experiment lasted for 63 days preceded by 10 days as a period of adaptation. As scheduled on day 49 of the trial and, to assess nutritional digestibility and N balance, five lambs were randomly selected. During this period, lambs were housed in metabolic cages that allowed the collection of total fecal and urinary outputs. Lambs were slaughtered to investigate carcass features on day 64. Acid detergent fiber and EE intakes were greater (p ≤ 0.007) in the JOJ100 than in CON diet. Nutrient digestibility, N balance, growth rate, and carcass traits were not affected (p ≥ 0.136) by consumption of JOJ100. Cost of production declined (p = 0.046) by 17% with the JOJ100 group. High-density lipoprotein was increased (p = 0.012) with lambs consuming the JOJ100 diet. In summary, adding jojoba meal to the diet of lambs appeared to have no adverse effect on their performance, carcass quality, or health. Most importantly, this dietary supplement appeared to enhance the economic efficiency by reducing the cost of production.

This study estimated the heritabilities (h2) and genetic and phenotypic correlations between reproductive traits, including calving interval (CI), age at first calving (AFC), gestation length (GL), number of artificial inseminations per conception (NAIPC), and carcass traits, including carcass weight (CWT), eye muscle area (EMA), backfat thickness (BF), and marbling score (MS) in Korean Hanwoo cows. In addition, the accuracy of genomic predictions of breeding values was evaluated by applying the genomic best linear unbiased prediction (GBLUP) and the weighted GBLUP (WGBLUP) method. The phenotypic data for reproductive and carcass traits were collected from 1,544 Hanwoo cows, and all animals were genotyped using Illumina Bovine 50K single nucleotide polymorphism (SNP) chip. The genetic parameters were estimated using a multi-trait animal model using the MTG2 program. The estimated h2 for CI, AFC, GL, NAIPC, CWT, EMA, BF, and MS were 0.10, 0.13, 0.17, 0.11, 0.37, 0.35, 0.27, and 0.45, respectively, according to the GBLUP model. The GBLUP accuracy estimates ranged from 0.51 to 0.74, while the WGBLUP accuracy estimates for the traits under study ranged from 0.51 to 0.79. Strong and favorable genetic correlations were observed between GL and NAIPC (0.61), CWT and EMA (0.60), NAIPC and CWT (0.49), AFC and CWT (0.48), CI and GL (0.36), BF and MS (0.35), NAIPC and EMA (0.35), CI and BF (0.30), EMA and MS (0.28), CI and AFC (0.26), AFC and EMA (0.24), and AFC and BF (0.21). The present study identified low to moderate positive genetic correlations between reproductive and CWT traits, suggesting that a heavier body weight may lead to a longer CI, AFC, GL, and NAIPC. The moderately positive genetic correlation between CWT and AFC, and NAIPC, with a phenotypic correlation of nearly zero, suggesting that the genotype-environment interactions are more likely to be responsible for the phenotypic manifestation of these traits. As a result, the inclusion of these traits by breeders as selection criteria may present a good opportunity for developing a selection index to increase the response to the selection and identification of candidate animals, which can result in significantly increased profitability of production systems.

Currently, in pork auctions in Korea, only carcass weight and backfat thickness provide information on meat quantity, while the production volume of primal cuts and fat contents remains largely unknown. This study aims to predict the production of primal cuts in pigs and investigate how these carcass traits affect pricing. Using the VCS2000, the production of shoulder blade, loin, belly, shoulder picnic, and ham was measured for gilts (17,257 pigs) and barrows (16,365 pigs) of LYD (Landrace × Yorkshire × Duroc) pigs. Single and multiple regression analysis were conducted to analyze the relationship between the primal cuts and carcass weight. The study also examined the correlation between each primal cut, backfat thickness (1st thoracic vertebra backfat thickness, grading backfat thickness, and Multi-brached muscle middle backfat thickness), pork belly fat percentage, total fat yield, and auction price. A multiple regression analysis was conducted between the carcass traits that showed a high correlation and the auction price. After conducting a single regression analysis on the primal cuts of gilt and barrow, all coefficients of determination (R2) were 0.77 or higher. In the multiple regression analysis, the R2 value was 0.98 or higher. The correlation coefficient between the carcass weights and the auction price exceeded 0.70, while the correlation coefficients between the primal cuts and the auction prices were above 0.65. In terms of fat content, the backfat thickness of gilt exhibited a correlation coefficient of 0.70, and all other items had a correlation coefficient of 0.47 or higher. The correlation coefficients between the Forequarter, Middle, and Hindquarter and the auction price were 0.62 or higher. The R2 values of the multiple regression analysis between carcass traits and auction price were 0.5 or higher for gilts and 0.4 or higher for barrows. The regression equations between carcass weight and primal cuts derived in this study exhibited high determination coefficients, suggesting that they could serve as reliable means to predict primal cut production from pig carcasses. Elucidating the correlation between primal cuts, fat contents and auction prices can provide economic indicators for pork and assist in guiding the direction of pig farming.

Abstract Background Carcass traits are essential economic traits in the commercial pig industry. However, the genetic mechanism of carcass traits is still unclear. In this study, we performed a genome-wide association study (GWAS) based on the specific-locus amplified fragment sequencing (SLAF-seq) to study seven carcass traits on 223 four-way intercross pigs, including dressing percentage (DP), number of ribs (RIB), skin thinkness (ST), carcass straight length (CSL), carcass diagonal length (CDL), loin eye width (LEW), and loin eye thickness (LET). Results A total of 227,921 high-quality single nucleotide polymorphisms (SNPs) were detected to perform GWAS. A total of 30 SNPs were identified for seven carcass traits using the mixed linear model (MLM) (p

Background: The Hanwoo industry must develop technologies that can increase the production of preferred cuts to match changing consumer trends. In this study, we aimed to estimate the genetic parameters for carcass traits (carcass weight, eye muscle area, back fat thickness, and intramuscular fat) and primal cut traits (tenderloin, loin, strip loin, neck, clod, top round, bottom round, brisket, shank, and rib) in a Hanwoo population to obtain basic data for improving primal cut productivity. Methods: Data from 1,905 Hanwoo steers, including carcass traits and primal cut weights, were collected. Genetic parameters were estimated using REMLF90 in a multi-trait analysis. Results: High heritability was found for carcass weight (0.52) and strip loin yield (0.63). Genetic correlations between carcass weight and primal cut weights ranged from 0.52 to 0.93. Conclusions: This study demonstrates the significant potential for genetic improvement in Hanwoo cattle through selective breeding, particularly for traits with high heritability and genetic correlations. These findings provide crucial insights into optimizing breeding programs to improve Hanwoo cattle production efficiency.

Background and Aim: Artemisia annua (AA), used as a growth promoter in poultry, lowers feed costs and enhances economic efficiency. This study aimed to assess the impact of varying AA concentrations on broiler chicken growth, gene expression, and profitability. Materials and Methods: Two hundred 1-day-old male Cobb chicks were randomly allocated into four treatment groups, each containing five replicates and 10 birds. The experimental groups consisted of G1 (basal diet), G2 (basal diet with 0.3% AA), G3 (basal diet with 0.6% AA), and G4 (basal diet with 0.9% AA). The birds had continuous access to feed and water throughout the study. The experiment lasted for 42 days. we measured the growth performance (Feed intake, Life weight), carcass traits (weight after slaughter, dressed carcass, heart, gizzard, spleen, giblet and thymus weight), liver and spleen antioxidants (CAT, GSH, SOD), and gene expression of anti-inflammatory and immune- related genes. Results: The primary findings revealed that the addition of 0.6% AA had a positive impact (p < 0.05) on all investigated variables compared with the control and other groups. Dietary supplementation with 0.6% AA led to increased breast, giblet, skeleton, and total yield, and net return compared with the control group. Supplementation with AA exhibited antioxidant, anti-inflammatory, and immunological effects through improved levels of antioxidant superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) in tissue homogenates of the liver and spleen. It also upregulated the relative messenger RNA levels of anti-inflammatory interleukin (IL)-10, SOD, CAT, and GSH-Px, whereas IL-1β and tumor necrosis factor-alpha were downregulated. Conclusion: The study found that AA is a promising replacement for antibiotics in poultry farming as a growth promoter for chickens. 0.6% AA in the broiler diet yielded the best results, striking a balance between superior performance and robust economic benefits.