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The current study aimed to compare the effects of increasing concentrations of dietary threonine (Thr), tryptophan (Trp), and glycine (Gly) on growth performance, stress biomarkers, and intestinal function in broiler chickens under multiple stress conditions. Five hundred sixty broiler chickens at 21 d old were randomly allotted to 5 treatments with 8 replicates. Birds in a positive control (PC) treatment were raised under low stock density (16.9 birds/m2 per cage) with recommended environmental conditions, whereas birds in 4 treatments were subjected to multiple stress conditions: a cyclic heat stress of 30 ± 0.3 °C for 10 h and 23 ± 0.2 °C for 14 h per day with high stock density (25.3 birds/m2 per cage). A basal diet was assigned to both PC and negative control (NC) treatments. Three additional diets were individually formulated to contain double concentrations of digestible Thr, Trp, or Gly + Ser compared with their concentrations in the basal diet. The experiment lasted for 14 d. Results showed that NC treatment had less growth performance (P

Objective The objective of the present study was to investigate the effect of dietary betaine (BT) supplementation on the hepatic transcriptome profiles in broiler chickens raised under heat stress (HS) conditions. Methods A total of 180 (21-d-old) Ross 308 male broiler chicks were allotted to 1 of 3 treatment groups with 6 replicated cages in a completely randomized design. One group was kept under thermoneutral conditions at all times and was fed a basal diet (PC). Other 2 groups were exposed to a cyclic heat stress condition. One of the 2 groups under heat stress conditions was fed the basal diet as a negative control (NC), whereas the other group was fed the basal diet supplemented with 0.2% BT. All chickens were provided with diets and water ad libitum for 21 d. Following the experiment, the liver samples were collected for RNA sequencing analysis. Results Broiler chickens in NC and BT group had decreased (p

The objective of this study was to investigate the protective effects of functional nutrients including various functional amino acids, vitamins, and minerals on chicken intestinal epithelial cells (cIECs) treated with oxidative stress. The cIECs were isolated from specific pathogen free eggs. Cells were exposed to 0 mM supplement (control), 20 mM threonine (Thr), 0.4 mM tryptophan (Trp), 1 mM glycine (Gly), 10 μM vitamin C (VC), 40 μM vitamin E (VE), 5 μM vitamin A (VA), 34 μM chromium (Cr), 0.42 μM selenium (Se), and 50 μM zinc (Zn) for 24 h with 6 replicates for each treatment. After 24 h, cells were further incubated with fresh culture medium (positive control, PC) or 1 mM H2O2 with different supplements (negative control, NC and each treatment). Oxidative stress was measured by cell proliferation, whereas tight junction barrier function was analyzed by fluorescein isothiocyanate (FITC)-dextran permeability and transepithelial electrical resistance (TEER). Results indicated that cell viability and TEER values were less (p < 0.05) in NC treatments with oxidative stress than in PC treatments. In addition, FITC-dextran values were greater (p < 0.05) in NC treatments with oxidative stress than in PC treatments. The supplementations of Thr, Trp, Gly, VC, and VE in cells treated with H2O2 showed greater (p < 0.05) cell viability than the supplementation of VA, Cr, Se, and Zn. The supplementations of Trp, Gly, VC, and Se in cells treated with H2O2 showed the least (p < 0.05) cellular permeability. In addition, the supplementation of Thr, VE, VA, Cr, and Zn in cells treated with H2O2 decreased (p < 0.05) cellular permeability. At 48 h, the supplementations of Thr, Trp, and Gly in cells treated with H2O2 showed the greatest (p < 0.05) TEER values among all treatments, and the supplementations of VC and VE in cells treated with H2O2 showed greater (p < 0.05) TEER values than the supplementations of VA, Cr, Se, and Zn in cells treated with H2O2. In conclusion, Thr, Trp, Gly, and VC supplements were effective in improving cell viability and intestinal barrier function of cIECs exposed to oxidative stress.

ABSTRACT: The current experiment aimed to investigate the effect of dietary glycine (Gly) supplementation on productive performance, egg quality, stress response, and fatty liver incidence in laying hens raised under heat stress (HS) conditions. A total of two hundred eighty 24-wk-old Lohmann Brown-Lite laying hens were randomly allotted to 1 of 4 dietary treatments with 7 replicates. The negative control (NC) diet was prepared to meet or exceed the nutrient and energy requirement for Lohmann Brown laying hens, whereas the positive control (PC) diet was formulated to increase AMEn by 100 kcal/kg compared with the NC diet. Two additional diets were prepared by supplementing 0.341% and 0.683% Gly to the NC diet. All hens were exposed to cyclic HS at 31.4 ± 1.17°C for 8 h/d and 26.7 ± 1.10°C for the remaining time for a 12-wk trial. Results indicated that increasing supplementation of Gly in diets tended (linear, P = 0.088) to decrease the FCR of laying hens. Increasing supplementation of Gly in diets increased (linear, P < 0.05) eggshell lightness and decreased (linear, P < 0.05) egg yolk color. Moreover, a tendency for a quadratic association (P < 0.10) of serum aspartate aminotransferase and alanine aminotransferase concentrations with increasing supplementation of Gly was observed. Increasing supplementation of Gly in diets decreased (linear, P < 0.05) blood heterophil:lymphocyte ratio of laying hens. Hens fed the NC diet showed higher fatty liver incidence (P < 0.05) than those fed the PC diet, but increasing supplementation of Gly decreased (linear, P < 0.05) fatty liver incidence of laying hens. In conclusion, increasing supplementation of Gly up to 0.683% in diets decreases FCR, stress response, and fatty liver incidence in laying hens raised under HS conditions.

ABSTRACT: This study aimed to investigate the effect of increasing fat supplementation in diets on productive performance, egg quality, and fatty liver incidence in laying hens during the entire laying cycle. A total of three hundred eighty-four 18-wk-old Hy-Line Brown laying hens were randomly allotted to 1 of 3 dietary treatments with 8 replicates for a 52-wk feeding trial. Each replicate comprised 16 consecutive cages with 1 hen per cage. The experimental diets were prepared by supplementing 0, 1.5, or 3.0% tallow to a basal diet, but all nutrients and energy in 3 diets were formulated to be equalized according to the recommended nutrient and energy concentrations at each phase of laying hens. Results indicated that increasing fat supplementation in diets decreased (linear, P < 0.01) feed conversion ratio (FCR) by increased egg mass (linear, P < 0.05) but decreased feed intake (linear and quadratic, P < 0.05) in laying hens during overall periods. Increasing fat supplementation in diets decreased (linear and quadratic, P < 0.05) egg yolk color during overall periods. Increasing fat supplementation in diets had no effects on liver color and hemorrhagic score measured at 60 wk (phase 3) and 70 wk of age (phase 4) without affecting hepatic fat concentrations during overall periods. However, the relative abdominal fat weight in laying hens was increased (linear and quadratic, P < 0.05) during overall periods by increasing fat supplementation in diets. In conclusion, increasing fat supplementation up to 3.0% in diets improves FCR with no impacts on fatty liver incidence and economics in laying hens throughout the entire laying cycle.

ABSTRACT: The current experiment was conducted to investigate the effect of individual or combination of dietary betaine (Bet) and glycine (Gly) on productive performance, stress response, liver health, and intestinal barrier function in broiler chickens raised under heat stress (HS) conditions. A total of four hundred twenty 21-d-old Ross 308 broiler chickens were randomly allotted to 1 of 5 dietary treatments with 7 replicates. Birds in treatment 1 were raised under the thermoneutral condition (TN; 23 ± 0.6°C). Birds in other 4 treatment groups were subjected to a cyclic HS by exposing them to 32 ± 0.9°C for 8 h/d (from 09:00 to 17:00 h) and 28 ± 1.2°C for the remaining time for 14 d. Birds were fed a basal diet in TN condition (TN-C) and one group in HS conditions (HS-C), whereas other birds raised under HS conditions were fed the basal diet supplemented with 0.20% Bet (HS-Bet), 0.79% Gly (HS-Gly), or their combination (0.20% Bet + 0.79% Gly; HS-Bet+Gly). Results indicated that birds in HS-Bet, HS-Gly, or HS-Bet+Gly treatment had higher (P < 0.05) final BW and BW gain, but lower (P < 0.05) feed conversion ratio (FCR) than those in HS-C treatment. However, values for improved final BW, BW gain, and FCR by dietary treatments were lower (P < 0.05) than those measured in TN-C treatment. Under HS conditions, birds in HS-Bet, HS-Gly, or HS-Bet+Gly treatment had lower (P < 0.05) heterophil to lymphocyte ratio than those in HS-C treatment. Birds in HS-Gly or HS-Bet+Gly treatment had higher (P < 0.05) villus height and goblet cell number than birds in HS-C treatment. Intestinal permeability was higher (P < 0.05) in all HS-treatment groups than in TN-C treatment, but it was not affected by dietary treatment. In conclusion, individual supplementation of 0.20% Bet or 0.79% Gly in diets alleviates the negative effect of HS in broiler chickens. However, the synergistic effect of the combination of 0.20% Bet and 0.79% Gly in broiler diets seems lower than expected.

Abstract Background Heat stress (HS) is one of the most important threats for the current poultry industry. Therefore, many efforts have been made to ameliorate the adverse effect of HS on poultry production; however, physiological and molecular mechanisms pertaining to HS are still limited in poultry. Therefore, the objective of the current study was to investigate functional alterations based on individual and integrated transcriptomes in the liver and jejunal mucosa tissues of broiler chickens exposed to HS conditions. Results Broiler chickens exposed to HS showed decreased growth performance and increased corticosterone concentrations in the feather. In the transcriptome analysis, the number of differentially expressed genes (DEGs) were identified in the liver and jejunal mucosa by HS conditions. In the liver, genes related to amino acid oxidation, tryptophan metabolism, lipid metabolism, oxidative phosphorylation, and immune responses were altered by HS, which support the reason why heat-stressed poultry had decreased productive performance. In the jejunal mucosa, genes related to defense systems, glutathione metabolism, detoxification of xenobiotics, and immune responses were differently expressed by HS conditions. The integrated transcriptome analysis with DEGs found in the liver and jejunal mucosa showed a considerable connectivity between the core nodes in the constructed networks, which includes glutathione metabolism, xenobiotic metabolism, carbon metabolism, and several amino acid metabolisms. Conclusions The core network analysis may indicate that increased requirement of energy and amino acids in the jejunal mucosa of broiler chickens exposed to HS conditions is likely compromised by increased oxidation and synthesis of amino acids in the liver. Therefore, our results may provide comprehensive insights for molecular and metabolic alterations of broiler chickens raised under HS conditions, which can aid in the development of the novel strategies to ameliorate the negative effect of HS on poultry productivity and health.

ABSTRACT: The objective of the current experiment was to investigate the effect of dietary concentrations of ME and neutral detergent fiber (NDF) on productive performance, egg quality, fatty liver incidence, and hepatic fatty acid metabolism in aged laying hens. A total of three hundred twenty 75-wk-old Hy-Line Brown laying hens were allotted to 1 of 4 dietary treatments with 8 replicates. Each replicate consisted of 10 consecutive cages with 1 hen per cage. The experiment was conducted using a completely randomized design with 2 × 2 factorial arrangement consisting of 2 levels of ME (normal [commercially recommended AMEn levels; 2,730 kcal/kg] and low [50 kcal/kg reduction in AMEn; 2,680 kcal/kg]) and 2 levels of NDF (low [9.01 and 9.61%; normal-ME and low-ME diets, respectively] and high [12.57 and 13.42%; normal-ME and low-ME diets, respectively]) in the diet. The diets and water were provided to hens on an ad libitum basis for 12 wk. Results indicated that no interactions between dietary concentrations of ME and NDF were observed for all measurements except for egg yolk color, eggshell thickness, and 2 hepatic gene expressions (i.e., carnitine palmitoyl transferase 1A and malic enzyme). For the main effects, increasing NDF concentrations in diets increased (P < 0.05) feed intake without affecting other productive performance. Hens fed normal-ME and high-NDF diets showed the darkest (P < 0.05) egg yolk color among those fed treatment diets, showing an interaction (P < 0.05). Increasing NDF concentrations in low-ME diets did not influence eggshell thickness, but those in normal-ME diets increased eggshell thickness in laying hens, showing an interaction (P < 0.05). For the main effects, increasing concentrations of dietary NDF or ME reduced (P < 0.05) hepatic fat concentrations with decreasing expressions in several genes related to fatty acid synthesis. In conclusion, increasing NDF concentrations in commercially-recommended ME diets decrease hepatic fat concentrations in aged laying hens, and therefore, may have a preventative effect on the fatty liver development in aged laying hens.

Objective The objective of the present study was to investigate the comparative effects of dietary functional nutrients including glutamine (Gln), chromium picolinate (Cr picolinate), vitamin C (Vit C), betaine (Bet), and taurine (Tau) on growth performance, meat quality, immune responses, and stress biomarkers in broiler chickens raised under heat stress conditions. Methods A total of 420 21-d-old Ross 308 male broiler chickens (initial body weight = 866±61.9 g) were randomly allotted to 1 of 7 treatment groups with 6 replicates. One group was kept under thermoneutral conditions and was fed a basal diet (PC, positive control). Other 6 groups were exposed to a cyclic heat stress condition. One of the 6 groups was fed the basal diet (NC, negative control), whereas 5 other groups were fed the basal diet supplemented with 0.5% Gln, 500 ppb Cr picolinate, 250 mg/kg Vit C, 0.2% Bet, or 1.0% Tau. The diets and water were provided ad libitum for 21 d. Results Broiler chickens in NC group had decreased (p

The objective of the present experiment was to investigate the effect of dietary palm kernel meal (PKM) and β-xylanase supplementation on productive performance, egg quality, fatty liver incidence, and excreta characteristics in laying hens. A total of 320 Hy-Line Brown laying hens (33 weeks of age) were allotted to 1 of 4 treatments with 8 replicates in a feeding trial. Each replicate consisted of 10 consecutive cages with 1 hen per cage. The corn-soybean meal-based control diet was prepared. Additional diet was prepared by including 10% of PKM in the control diet with a partial replacement of corn, soybean meal, and animal fat. In addition, 0.025% β-xylanase was supplemented at the expense of celite to those 2 diets to produce 4 treatment diets in a 2 × 2 factorial arrangement. All hens were provided the diet and water ad libitum for 8 weeks. Results indicated no significant interactions between inclusion of dietary PKM and β-xylanase for all measurements; therefore, the main effects were mainly discussed. Hens fed diets containing 10% PKM had greater (p < 0.05) feed intake and yolk color than those fed diets containing no PKM. However, dietary PKM did not influence fatty liver incidence and excreta characteristics. Dietary β-xylanase supplementation had no effects on all measurements, regardless of inclusion of PKM. In conclusion, PKM can be a potential feed ingredient for laying hens at the inclusion of 10% in the diet. It appears that dietary β-xylanase used in the current experiment has little effect on layer productivity, regardless of inclusion of 10% PKM in the diet.

Objective The objective of the current study was to investigate the effects of dietary hatchery by-products (HBPs) as a replacement of fish meal (FM) on growth performance, relative organ weight, plasma measurements, immune organ index, meat quality, and tibia characteristics of broiler chickens. Methods A total of 720 broiler chickens (3 d of age) were randomly allotted to 1 of 9 treatments with 8 replicates. Each replicate consisted of 5 male and 5 female birds. The basal diet was formulated to contain 5.0% commercial FM, whereas eight treatment diets were prepared by replacing 25%, 50%, 75%, or 100% of FM in the basal diet with infertile eggs (IFE) or a mixture of various HBPs (MIX); therefore, the inclusion levels of IFE or MIX in the experimental diets were 1.25%, 2.50%, 3.75%, or 5.00%. The diets and water were provided on an ad libitum basis for 32 d. Results Increasing inclusion levels of IFE as a replacement of FM in diets had no effects on growth performance, plasma measurements, immune organ index, and tibia characteristics of broiler chickens. Increasing inclusion levels of IFE in diets increased (linear, p

The objective of the current study was to investigate the effects of stocking density (SD) and dietary supplementation of vitamin C on growth performance, meat quality, intestinal permeability, and stress indicators in broiler chickens. The study was conducted using a completely randomized design with a 2 × 2 factorial arrangement consisting of 2 different SD and 2 supplemental levels of dietary vitamin C. A total of 1,368 Ross 308 broiler chickens of 21 days of age with similar body weights (BW) were randomly allotted to 1 of 4 treatments with 6 replicates each. Different numbers of birds per identical floor pen (2.0 m × 2.4 m) were used to create 2 different SD levels of low SD (9 birds/m2) and high SD (18 birds/m2). The basal diet was formulated with no supplemental vitamin C to meet or exceed nutrient recommendations of the Ross 308 manual. The other diet was prepared by supplementing 200 mg/kg vitamin C in the basal diet. The study lasted for 14 days. At the end of the study, 3 male birds per replicate were selected to analyze meat quality, intestinal permeability, and stress indicators such as blood heterophil:lymphocyte (H:L) and feather corticosterone (CORT) concentrations. Results indicated that there were no interactions between different SD and dietary supplementation of vitamin C for all measurements. For the main effects of SD, birds raised at high SD had less (p < 0.01) BW, BW gain, and feed intake with increasing stress responses including greater blood H:L and feather CORT concentrations (p < 0.01) than those raised at low SD. Transepithelial electrical resistance in the jejunal mucosa was decreased (p < 0.05) at high SD, indicating an increase in intestinal permeability. However, the main effects of dietary supplementation of 200 mg/kg vitamin C were insignificant for all measurements. In conclusion, high SD of broiler chickens impairs growth performance and intestinal barrier function with increasing stress responses. However, dietary supplementation of vitamin C may have little beneficial effects on broiler chickens raised at the high SD condition used in the present study.

Objective Eggshell color is an important indicator of egg quality for consumers, especially for brown eggs. Various factors related to laying hens and their environment affect brown eggshell coloration. However, there have been no studies investigating hepatic functions of laying hens with variable intensity of brown eggshell color. Therefore, this study was aimed to identify potential factors affecting brown eggshell coloration in aged laying hens at the hepatic transcriptomic level. Methods Five hundred 92-wk-old Hy-line Brown laying hens were screened to select laying hens with different intensity of brown eggshell color based on eggshell color fans. Based on eggshell color scores, hens with dark brown eggshells (DBE; eggshell color fan score = 14.8) and hens with light brown eggshells (LBE; eggshell color fan score = 9.7) were finally selected for the liver sampling. We performed RNA-seq analysis using the liver samples through the paired-end sequencing libraries. Differentially expressed genes (DEGs) profiling was carried out to identify their biological meaning by bioinformatics. Results A total of 290 DEGs were identified with 196 being up-regulated and 94 being down-regulated in DBE groups as compared to LBE groups. The Kyoto encyclopedia of genes and genomes (KEGG) analysis revealed that these DEGs belong to several biological pathways including herpes simplex infection (toll-like receptor 3 [TLR3], cyclin-dependent kinase 1, etc.) and influenza A (TLR3, radical S-adenosyl methionine domain containing 2, myxovirus [influenza virus] resistance 1, etc.). Genes related to stress response (ceremide kinase like) and nutrient metabolism (phosphoenolpyruvate carboxy-kinase 1, methylmalonic aciduria [cobalamin deficiency] cblB type, glycine receptor alpha 2, solute carrier family 7 member 11, etc.) were also identified to be differentially expressed. Conclusion The current results provide new insights regarding hepatic molecular functions related to different intensity of brown eggshell color in aged laying hens. These insights will contribute to future studies aiming to optimize brown eggshell coloration in aged laying hens.

ABSTRACT: The objective of the current experiment was to compare various stress biomarkers including the heterophil to lymphocyte ratio (H:L ratio) in blood and the corticosterone (CORT) concentrations in feathers, claws, and egg yolk and to find the potential stress biomarkers in laying hens exposed to a long-term multiple stress condition. A total of 24 Hy-Line Brown laying hens at 47 wk of age were allotted to 2 distinct conditions including normal condition (NC) and multiple stress condition (MC) with 8 replicated cages. In NC treatment, 8 hens were raised individually in the cage (0.16 m2/hen) under the temperature of 21 ± 0.6°C. In MC treatment, 16 hens were raised with 2 hens per cage to decrease space allowance (0.08 m2/hen) and the temperature was maintained at 31 ± 1.6°C. The experiment lasted for 8 wk. The common diets and water were fed on an ad libitum basis during the experiment. Results indicated no interactions between stress conditions and duration of stress exposure for all measurements. Hens in MC treatment had a greater (P < 0.01) blood H:L ratio than those in NC treatment. The greater (P < 0.05) H:L ratio for MC treatment was observed at all weeks. Hens in MC treatment had greater (P < 0.05) feather CORT concentrations than those in NC treatment. Feather CORT concentrations were increased (P < 0.05) with duration of the experiment. However, stress conditions did not influence claw CORT concentrations. A tendency (P = 0.081) was observed for greater yolk CORT concentrations in MC treatment than in NC treatment. In conclusion, the H:L ratio in blood and CORT concentrations in feathers and egg yolks are considered potential stress biomarkers in laying hens exposed to stress conditions, although each measurement has its respective limitations. However, CORT concentrations in the claw appear to be insensitive to a long-term stress exposure.

The present experiment aimed to compare toxic effects of dietary organic or inorganic selenium (Se) and to predict of Se intake and tissue Se concentrations in broiler chickens based on feather Se concentrations. A total of four hundred twenty 7-day-old Ross 308 male broiler chicks were allotted to 1 of 7 dietary treatments in a completely randomized design. Each treatment had 6 replicates with 10 birds per replicate. Organic Se (selenium yeast) or inorganic Se (sodium selenite) was added to the basal diet at the levels of 5, 10, or 15 mg/kg Se. All experimental diets were fed to birds on an ad libitum basis for 28 d. Results indicated that a significant interaction (P

ABSTRACT: The objective of the current experiment was to investigate the effect of dietary magnesium (Mg) and δ-aminolevulinic acid (ALA) supplementation on productive performance and egg quality in laying hens. The present experiment was performed using a completely randomized design with 2 × 2 factorial arrangements including 2 levels of supplemental Mg (0 and 0.12%) and ALA (0 and 0.25%) in diets. A total of 192 43-wk-old Hy-Line Brown laying hens were allotted to 1 of 4 dietary treatments with 6 replicates. Each replicate consisted of 4 consecutive cages with 2 hens per cage. Treatment diets were fed to hens for 6 wk. Results indicated that dietary Mg supplementation improved (P < 0.01) eggshell strength but decreased (P < 0.05) eggshell color score, regardless of dietary ALA supplementation. However, the decreased eggshell color by dietary Mg supplementation was relieved by dietary ALA supplementation, which led to a significant interaction (P < 0.05). Likewise, an interaction (P < 0.05) was also observed for eggshell lightness (L*) because dietary ALA supplementation decreased eggshell L* values only when Mg was supplemented to diets. In conclusion, dietary Mg supplementation improves eggshell strength but decreases the intensity of brown eggshell color in laying hens. However, this negative effect of dietary Mg supplementation on eggshell color is likely ameliorated by dietary ALA supplementation.

ABSTRACT: The objective of the present experiment was to determine ME concentrations and amino acid (AA) digestibility in various hatchery byproducts (HBPs) for broiler chickens. In experiment 1, a total of forty 60-day-old female broiler chickens were allotted to 1 of 5 dietary treatments with 8 replicates and used to measure ME concentrations in HBPs. The basal diet was prepared to contain corn, soybean meal, corn oil, and other non-energy ingredients. Additional 4 experimental diets were prepared to contain 10% of infertile eggs (IFE), unhatched eggs (UHE), low-grade or dead chicks (LDC), and mixture (MIX; 55% IFE, 10% UHE, 10% LDC, and 25% hatched eggshells). In experiment 2, a total of seven hundred and sixteen 1-day-old mixed-sex broiler chickens (1:1 ratio of males and females) were allotted to 1 of 5 dietary treatments with 7 replicates per treatment and used to determine apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of AA in HBPs. The experimental diets consisted of a nitrogen-free diet and 4 diets containing IFE, UHE, LDC, or MIX as a sole source of AA. Results indicated that AME and AMEn values were greater (P < 0.05) for LDC than for IFE, which had greater (P < 0.05) AME and AMEn values for UHE and MIX. The AID and SID of most AA in LDC were greater (P < 0.05) than those in MIX, whereas IFE and UHE had intermediate AID and SID of those AA as compared to LDC and MIX. Average SID of essential AA in LDC was greater (P < 0.05) than in UHE and MIX, but the average SID of nonessential AA did not differ among 4 HBPs. In conclusion, LDC has the greatest ME concentrations and AA digestibility among 3 individual HBPs (IFE, UHE, and LDC). The mixture of HBPs has the least ME concentrations and AA digestibility in broiler chickens. The ME and AA digestibility of HBPs are likely affected by inclusion amounts of hatched eggshells. However, high concentrations of ME and available AA demonstrate that individual HBPs and their mixture are potential protein ingredients for broiler diets.

The present study was conducted to test whether the dietary supplementation of β-mannanase affects amino acids (AA) digestibility, metabolizable energy (ME) contents of corn, wheat, soybean meal, distillers dried grains with solubles, and palm kernel meal (PKM), nutrient digestibility, and growth performance of pigs. In Exp. 1, 22 cannulated pigs were used for 10 dietary treatments including 5 feed ingredients and 2 β-mannanase concentrations (0 and 0.5 g/kg of the diet) in 6 periods in an incomplete Latin square design to determine the AA and energy digestibility. In Exp. 2, 200 growing pigs were randomly allotted to 4 treatments with 2 nutrient levels (high and low) and 2 concentrations of β-mannanase (2 × 2 factorial arrangement) in 2 phases (phase 1, d 0 to 21; and phase 2, d 22 to 42). In Exp. 1, β-mannanase increased the mean standardized ileal digestibility (SID) of AA in all feed ingredients. The amount of digestible energy was increased (P

Objective As laying hens become aged, laying performance and egg quality are generally impaired. One of the practical methods to rejuvenate production and egg quality of aged laying hens with decreasing productivity is a forced molting. However, the changes in intestinal microbiota after forced molting of aged hens are not clearly known. The aim of the present study was to analyze the changes in excreta bacterial communities after forced molting of aged laying hens. Methods A total of one hundred 66-wk-old Hy-Line Brown laying hens were induced to molt by a 2-d water removal and an 11-d fasting until egg production completely ceased. The excreta samples of 16 hens with similar body weight were collected before and immediately after molting. Excreta bacterial communities were analyzed by high-throughput sequencing of bacterial 16S rRNA genes. Results Bacteroidetes, Firmicutes, and Proteobacteria were the three major bacterial phyla in pre-molting and immediate post-molting hens, accounting for more than 98.0%. Lactobacillus genus had relatively high abundance in both group, but decreased by molting (62.3% in pre-molting and 24.9% in post-molting hens). Moreover, pathogenic bacteria such as Enterococcus cecorum and Escherichia coli were more abundant in immediate post-molting hens than in pre-molting hens. Forced molting influenced the alpha diversity, with higher Chao1 (p = 0.012), phylogenetic diversity whole tree (p = 0.014), observed operational taxonomic unit indices (p = 0.006), and Simpson indices (p

Objective This experiment aimed to investigate the effect of different sources and inclusion levels of dietary fat on productive performance and egg quality in laying hens raised under hot environmental conditions. Methods A total of 480 Hy-Line Brown laying hens at 31 wk of age were randomly allotted to 1 of 5 experimental diets. The control diet contained 2,800 kcal/kg nitrogen-corrected apparent metabolizable energy with no fat addition. Four additional diets were prepared by adding 2.0% or 4.0% of animal fat (AF) or soybean oil (SO). Energy and nutrient concentrations were consistent among all diets. Diets were fed to hens for 4 weeks. Average daily room temperature and humidity were 26.7°C±1.52°C and 77.4%±4.50%. The heat stress index was approximately 76, indicating that hens were raised under heat stress conditions. Results Final body weight (BW) was greater (p

Background: High amounts of nonstarch polysaccharides in the diet may increase the amounts of fermentative materials in the hindgut, leading to an increase in fermentative heat production. Dietary β-mannanase is reported to decrease antinutritional effects of β-mannans, such as the potential increase of body heat; however, its efficacy on broiler chickens raised under hot climatic conditions has not been investigated. Objective: To investigate the effects of dietary β-mannanase on growth performance, cloacal temperature, relative lymphoid organ weight, and blood characteristics of broiler chickens raised under hot climatic conditions. Methods: A total of 1,701 1-day-old Ross 308 broiler chickens were randomly allotted to one of three dietary treatments with nine replicates. A basal diet was prepared and added with β-mannanase at 0.05 or 0.10% inclusion levels. The experiment was conducted for 30 days. Average room temperature was 28.8 ± 1.74 ̊C and average relative humidity (RH) was 76.1 ± 11.49% during the experiment. Results: Growth performance of broiler chickens raised under hot climatic conditions was not affected by β-mannanase inclusion. Cloacal temperature decreased at the end of experiment (linear, p

Abstract Background There are various fat sources with different energy values and fatty acid compositions that may affect growth performance and carcass composition of grow-finishing pigs. A higher net energy was recently reported in choice white grease compared with soybean oil. Therefore, two experiments were conducted to determine whether practical responses confirm that difference between choice white grease and soybean oil, and to extend the observations to other fat sources. Results In Exp. 1, pigs fed fats had lower (P

Objective This experiment was conducted to determine the effects of dietary β-mannanase on the additivity of true metabolizable energy (TME) and nitrogen-corrected true metabolizable energy (TMEn) for broiler diets. Methods A total of 144 21-day-old broilers were randomly allotted to 12 dietary treatments with 6 replicates. Five treatments consisted of 5 ingredients of corn, wheat, soybean meal, corn distillers dried grains with solubles, or corn gluten meal. One mixed diet containing 200 g/kg of those 5 ingredients also was prepared. Additional 6 treatments were prepared by mixing 0.5 g/kg dietary β-mannanase with those 5 ingredients and the mixed diet. Based on a precision-fed chicken assay, TME and TMEn values for 5 ingredients and the mixed diet as affected by dietary β-mannanase were determined. Results Results indicated that when β-mannanase was not added to the diet, measured TME and TMEn values for the diet did not differ from the predicted values for the diet, which validated the additivity. However, for the diet containing β-mannanase, measured TMEn value was greater (p

Objective The objective of this experiment was to investigate the effect of dietary β-mannanase on productive performance, egg quality, and utilization of dietary energy and nutrients in aged laying hens raised under hot climatic conditions. Methods A total of 320 84-wk-old Hy-line Brown aged laying hens were allotted to one of four treatments with eight replicates in a completely randomized design. Two dietary treatments with high energy (HE; 2,800 kcal/kg nitrogen-corrected apparent metabolizable energy [AMEn]) and low energy (LE; 2,700 kcal/kg AMEn) were formulated. Two additional diets were prepared by adding 0.04% (MN4) or 0.08% β-mannanase (MN8) to LE treatment diets. The feeding trial was conducted for 28 d, covering a period from July to August in South Korea. The average daily room temperature and relative humidity were 29.2°C and 83%, respectively. Results Productive performance, egg quality, and cloacal temperature were not influenced by dietary treatments. The measured AMEn values for MN8 diets were similar to those for HE diets, which were greater (p

Objective This experiment investigated the effect of dietary net energy (NE) concentrations on growth performance and NE intake of growing gilts. Methods Five diets were formulated to contain 9.6, 10.1, 10.6, 11.1, and 11.6 MJ NE/kg, respectively. A metabolism trial with 10 growing pigs (average body weight [BW] = 15.9±0.24 kg) was conducted to determine NE concentrations of 5 diets based on French and Dutch NE systems in a 5×5 replicated Latin square design. A growth trial also was performed with five dietary treatments and 12 replicates per treatment using 60 growing gilts (average BW = 15.9±0.55 kg) for 28 days. A regression analysis was performed to predict daily NE intake from the BW of growing gilts. Results Increasing NE concentrations of diets did not influence average daily gain and average daily feed intake of growing gilts. There was a quadratic relationship (p = 0.01) between dietary NE concentrations and feed efficiency (G:F), although the difference in G:F among treatment means was relatively small. Regression analysis revealed that daily NE intake was linearly associated with the BW of growing gilts. The prediction equations for NE intake with the BW of growing gilts were: NE intake (MJ/d) = 1.442+(0.562×BW, kg), R2 = 0.796 when French NE system was used, whereas NE intake (MJ/d) = 1.533+(0.614×BW, kg), R2 = 0.810 when Dutch NE system was used. Conclusion Increasing NE concentrations of diets from 9.6 to 11.6 MJ NE/kg have little impacts on growth performance of growing gilts. Daily NE intake can be predicted from the BW between 15 and 40 kg in growing gilts.

Objective An experiment was conducted to investigate the effect of dietary Ca concentrations in low non-phytate phosphorus (NPP) diets containing phytase on growth performance, bone mineralization, litter quality, and footpad dermatitis (FPD) incidence in growing broiler chickens. Methods A total of 1,800 21-day-old Ross 308 growing broiler chickens were allotted to 1 of 6 dietary treatments with 6 replicated cages. Six diets were formulated to provide increasing Ca concentrations of 4.0, 5.0, 6.0, 7.0, 8.0, or 9.0 g/kg in diets. The concentrations of NPP in all diets were maintained at 3.0 g/kg, and phytase was supplemented to all diets at the level of 1,000 fytase units (FTU)/kg. At the end of the 14-d feeding trial, birds were euthanized for tibia sampling, and litter samples were collected from 3 areas in the cage. The FPD incidence was measured based on a 6-point scoring system. Results Dietary Ca concentrations had no effect on growth performance of growing broiler chickens. However, a tendency (linear, p = 0.05) for decreased feed efficiency was observed as dietary Ca concentrations were increased. The concentrations of Ca and P in the tibia of broiler chickens increased (linear and quadratic, p

Objective An experiment was conducted to determine the effect of superdosing phytase on productive performance and egg quality in laying hens. Methods A total of 200 42-wk-old Hy-Line Brown laying hens were allotted into 1 of 5 dietary treatments with 5 replicates consisting of 8 hens per replicate. The positive control (PC) and negative control diets (NC) were prepared based on the recommended P levels in layer diets. Supplemental phytase was added to the negative control diet at 10,000 (SD10), 20,000 (SD20), or 30,000 (SD30) fytase units (FTU)/kg. Productive performance was summarized for 6 weeks from 42 weeks to 47 weeks of age. Egg quality was assessed from 4 eggs per replicate randomly collected at the conclusion of the experiment. Results The SD20 treatment had greater (p

The objectives of the current experiment were to study the response of the growth performance of early finishing gilts to different net energy (NE) concentrations in diets, and to compare the NE values of diets between calculated NE values and measured NE values using French and Dutch CVB (Centraal Veevoederbureau; Central Bureau for Livestock Feeding) NE systems. In a metabolism trail, the NE concentrations in five diets used for the growth trial were determined based on digestible nutrient concentrations, digestible energy, and metabolizable energy using a replicated 5×5 Latin square design with 10 barrows (initial body weight [BW], 39.2±2.2 kg). In a growth trial, a total of 60 early finishing gilts (Landrace×Yorkshire; initial BW, 47.7±3.5 kg) were allotted to five dietary treatments of 8.0, 9.0, 10.0, 11.0, and 12.0 MJ NE/kg (calculated, as-is basis) with 12 replicate pens and one pig per pen in a 42-d feeding experiment. The NE and amino acid (AA) concentrations in all diets were calculated based on the values from NRC (2012). Ratios between standardized ileal digestible AA and NE concentrations in all diets were closely maintained. Pigs were allowed ad libitum access to feed and water. Results indicated that calculated NE concentrations in diets (i.e., five dietary treatments) were close to measured NE concentrations using French NE system in diets. The final BW was increased (linear and quadratic, p

Background: of distillers dried grains with solubles (DDGS) in lactation diets may contribute to productive performance of lactating sows of different parities. Objective: the objective of this study was to determine the effects of feeding diets containing different levels of DDGS on productive performance of lactating sows of different parities. Methods: a total of 245 sows were divided into 3 parity groups of 1 to 2, 3 to 5, and over 5 parities. Within each parity group, sows were allotted to 1 of 4 dietary treatments that were prepared by inclusion of 0, 10, 20, and 30% DDGS in lactation diets. Diets were fed to sows during the whole lactation period. Results: average piglet weaning weight tended (quadratic, p

The present experiment was conducted to investigate the effect of heat stress (HS) and stocking density (SD) on growth performance, breast meat quality, and intestinal barrier function in broiler chickens. Experimental treatments included two different ambient temperatures (20 °C: thermoneutral conditions, or 27.8 °C: HS conditions) and two different SD (low: 9 birds/m2 and high: 18 birds/m2) in a 2 × 2 factorial arrangement. A total of 1140 21-day-old broiler chickens were allotted 1 of 4 treatments with five replicates. At the end of the experiment (35 days of age), two birds per replicate were euthanized for sample collections. The results indicated no interactions between HS and SD for all measurements. For main effects, HS decreased (p < 0.05) the growth performance of broiler chickens. Similarly, high SD also decreased (p < 0.05) body weight gain and feed intake. HS decreased (p < 0.01) jejunal trans-epithelial electric resistance (TER), whereas high SD did not affect TER. Neither HS nor high SD affected jejunal tight junction-related gene expressions; however, high SD reduced (p < 0.05) occludin expression. In conclusion, HS and high SD are key environmental factors decreasing broiler performance; however, the interactive effects of HS and high SD are not significant under the current conditions.

An experiment was conducted to evaluate the effect of dietary supplementation of histidine, β-alanine, blood meal (BM), magnesium oxide (MgO), and their combination on carnosine and anserine concentrations of broiler breast meat. A total of 210 1-d-old broiler chicks were randomly allotted to 3 replicates of 7 dietary treatments: (1) Control diet (C), (2) C+histidine (His), (3) C+β-alanine (β-Ala), (4) C+histidine+β-alanine (His+β-Ala ); (5) C+histidine+β-alanine+MgO (His+β-Ala+MgO), (6) C+5% BM (BM), and (7) C+5% BM+MgO (BM+MgO). Histidine, β-alanine, and MgO were supplemented to diets at 2.9, 3.7, and 4.0 g/kg diet, respectively. The broilers were fed experimental diets for 32 d and the concentrations of carnosine and anserine in breast meat were measured weekly and at 32 d of the age. Results indicated that the concentrations of carnosine, anserine, and their sum in breast meat were increased (linear, P

The objective of this experiment was to measure the effects of soybean oil (SBO) and choice white grease (CWG) on apparent ileal digestibility (AID) of amino acids (AA) in corn-soybean meal-distillers dried grains with solubles-based diets fed to growing pigs. Three diets were prepared. The control diet contained corn, soybean meal, distillers dried grains with solubles (DDGS), cornstarch, and no additional fat. Two additional diets were formulated by adding 5% SBO or 5% CWG to the control diet at the expense of cornstarch. Twelve growing barrows with initial body weight of 37.6 kg (standard deviation = 3.22) were equipped with a T-cannula at the end of the ileum and they were allotted to one of three dietary treatments during six experimental periods.The AID of indispensable AA (e.g., arginine, histidine, isoleucine, leucine, phenylalanine, and valine) and dispensable AA (e.g., alanine, aspartic acid, cysteine, and proline) was improved (pEl objetivo de este experimento fue medir el efecto del aceite de soya (SBO) y la grasa blanca (grasa de cerdo, CWG) sobre la digestibilidad ileal aparente (DIA) de aminoácidos (AA) en dietas maíz-soya adicionadas con derivados solubles de destilería para cerdos en crecimiento. Tres dietas fueron preparadas. La dieta control contenía maíz, harina de soya, granos secos de destilería con solubles (DDGS), almidón de maíz, y sin grasa adicionada. Dos dietas adicionales fueron formuladas adicionando 5% de SBO o de GTC a la dieta control, a expensas de la fécula de maíz. Doce cerdos machos castrados, con peso inicial de 37.6 kg (desviación estándar =3.22), fueron equipados con una cánula en T en el extremo del íleo y fueron asignados a uno de los tres tratamientos dietarios durante seis periodos experimentales. La DIA de AA esenciales (por ejemplo, arginina, histidina, isoleucina, leucina, fenilalanina y valina) y no esenciales (por ejemplo, alanina, ácido aspártico, cisteína y prolina) se mejoró (pO objectivo deste experimento foi avaliar o efeito do óleo de soja (SBO) e gordura branca (de suino, CWG) sobre a digestibilidade ileal aparente (AID) de aminoácidos (AA) em dietas com adição de derivados de milho-soja solúvel de destilaria para suínos em crescimento. Três dietas foram preparadas. A dieta controle continha milho, farelo de soja, grãos secos de destilaria com solúveis (DDGS), amido de milho, e não tinha gordura adicionada. As outras duas dietas tinham uma adição de 5% SBO e a outra com 5% de GTC à custa de amido de milho. Doze suínos machos castrados, com peso inicial de 37.6 kg (DP = 3.22) foram equipados com uma cânula T no final do íleo. O núcleo do AA (por exemplo, arginina, histidina, isoleucina, leucina, fenilalanina e valina) e não-essenciais (por exemplo, alanina, ácido aspártico, cisteína e prolina) foi melhorada (p

The objective of the present review is to provide an overview on the effects of the addition of acidifiers to nursery pig diets. Researchers have proposed that dietary acidifiers decrease pH in the stomach and the lower gastrointestinal tract (GIT) of weanling pigs, and thus, protect the host from pathogenic invasion and proliferation and improve nutrient digestion. These benefits may subsequently result in improved growth performance of weanling pigs. In experiments on nursery pigs, dietary acidifiers decreased stomach pH at least to a small extent, but had little influence on the pH of the lower GIT. Studies found no observable changes in microbial populations upon providing weanling pigs with dietary acidifiers, but they found a slight reduction in lactobacilli or lactic acid-producing bacteria throughout the GIT. Dietary acidifiers improved protein digestion in many cases despite variable results regarding the digestibility of amino acids and improved growth performance. Such positive responses were more apparent during the first or second week of experiments than the later stages. However, growth responses were inconsistent among different sources and varying inclusion rates of acidifiers. Information on the dietary acidifiers’ mode of action is quite limited, and large variations exist in results regarding the effects of dietary acidifiers. Based on the present review, the benefit of dietary acidifiers for nursery pigs is not entirely convincing. Further research is required to clarify the acidifiers’ mode of action and its association with subsequent growth performance in weanling pigs.El objetivo de esta revisión es ofrecer una visión general sobre los efectos de la adición de acidificantes orgánicos en la dieta de cerdos destetos. Se ha propuesto que los acidificantes dietarios reducen el pH en el estómago y tracto gastrointestinal (TGI) de los cerdos recién destetados, y por lo tanto protegen al huésped de la invasión y proliferación de patógenos, al tiempo que mejoran la digestión de nutrientes. Estos beneficios podrían resultar en una mejora del crecimiento de dichos animales. En experimentos con cerdos destetados, los acidificantes dietarios han mostrado que pueden disminuir el pH del estómago, al menos en pequeña medida, pero han tenido poca influencia en el pH del tracto gastrointestinal posterior. Algunos estudios no encontraron cambios observables en las poblaciones microbianas al ofrecer acidificantes en la dieta a estos animales, pero se reporta una ligera reducción de los lactobacilos o bacterias lácticas productoras de ácido en todo el tracto gastrointestinal. En muchos casos, los acidificantes parecen mejorar la digestión proteica, a pesar de ofrecer resultados variables con respecto a la digestibilidad de los aminoácidos y mejora del crecimiento. Tales respuestas positivas parecen ser más evidentes durante la primera o segunda semana de los experimentos que en etapas posteriores. Sin embargo, la respuesta en crecimiento ha sido inconsistente respecto a diferentes fuentes y niveles de inclusión de acidificantes. La información sobre el modo de acción de los acidificantes dietarios es bastante limitada y existen grandes variaciones en los resultados respecto a sus efectos. De acuerdo con esta revisión, el beneficio potencial de los acidificantes dietarios en cerdos destetados no está del todo justificado. Se requiere investigación adicional para aclarar su modo de acción y su relación con el crecimiento de los cerdos recién destetados.O objetivo desta revisão é fornecer uma visão geral dos efeitos da adição de acidificantes orgânicos na dieta de leitões desmamados. Tem sido proposto que a dieta acidificante reduz o pH do estômago e do trato gastrointestinal (TGI) de leitões desmamados, e assim proteger o hospedeiro da invasão e proliferação de patogênicos, melhorando a digestão dos nutrientes. Estes podem resultar em um maior crescimento destes animais. Em experimentos com suínos desmamados, a acidificação da dieta têm sido mostrados para diminuir o pH do estômago, pelo menos em pequena medida, mas tiveram pouca influência sobre o pH do trato gastrointestinal posterior. Alguns estudos não encontraram alterações observáveis em populações microbianas ao oferecer acidificantes na dieta, mas tem-se reportado uma ligeira redução de lactobacilos ou bactérias lácticas produtoras de ácido em tudo o trato gastrointestinal. Em muitos casos, os acidificantes parecem melhorar a digestão de proteínas, apesar de oferecer resultados variáveis com respeito à digestibilidade dos aminoácidos e melhora o crescimento. ais respostas positivas parecem ser mais evidentes durante a primeira ou segunda. No entanto, a resposta de crescimento tem sido inconsistente com relação a diferentes fontes e níveis de inclusão de acidificantes. A Informação sobre o modo de ação dos acidificantes na dieta é bastante limitado e existem grandes variações nos resultados sobre seus efeitos. De acordo com essa análise, o benefício potencial de alimentar leitões desmamados com acidificantes não é inteiramente justificado. Mais pesquisas são necessárias para esclarecer seu modo de ação e sua relação com o crescimento de leitões desmamados.

Interleukin-34 (IL-34) is a newly recognized cytokine with functions similar to macrophage colony-stimulating factor 1. It is expressed in macrophages and fibroblasts, where it induces cytokine production; however, the mechanism of chicken IL-34 (chIL-34) signaling has not been identified to date. The aim of this study was to analyze the signal transduction pathways and specific biological functions associated with chIL-34 in chicken macrophage (HD11) and fibroblast (OU2) cell lines. We found that IL-34 is a functional ligand for the colony-stimulating factor receptor (CSF-1R) in chicken cell lines. Treatment with chIL-34 increased the expression of Th1 and Th17 cytokines through phosphorylation of tyrosine and serine residues in Janus kinase (JAK) 2, tyrosine kinase 2 (TYK2), signal transducer and activator of transcription (STAT) 1, STAT3, and Src homology 2-containing tyrosine phosphatase 2 (SHP-2), which also led to phosphorylation of NF-κB1, p-mitogen-activated protein kinase kinase kinase 7 (TAK1), MyD88, suppressor of cytokine signaling 1 (SOCS1), and extracellular signal-regulated kinase 1 and 2 (ERK1/2). Taken together, these results suggest that chIL-34 functions by binding to CSF-1R and activating the JAK/STAT, nuclear factor κ B (NF-κB), and mitogen-activated protein kinase signaling pathways; these signaling events regulate cytokine expression and suggest roles for chIL-34 in innate and adaptive immunity.

BACKGROUND: The liver plays a central role in nutrient and xenobiotic metabolism, but its functionality declines with age. Senior dogs suffer from many of the chronic hepatic diseases as elderly humans, with age-related alterations in liver function influenced by diet. However, a large-scale molecular analysis of the liver tissue as affected by age and diet has not been reported in dogs. METHODOLOGY/PRINCIPAL FINDINGS: Liver tissue samples were collected from six senior (12-year old) and six young adult (1-year old) female beagles fed an animal protein-based diet (APB) or a plant protein-based diet (PPB) for 12 months. Total RNA in the liver tissue was extracted and hybridized to Affymetrix GeneChip® Canine Genome Arrays. Using a 2.0-fold cutoff and false discovery rate

BACKGROUND: We have previously reported the effects of age and diet on nutrient digestibility, intestinal morphology, and large intestinal fermentation patterns in healthy young adult and senior dogs. However, a genome-wide molecular analysis of colonic mucosa as a function of age and diet has not yet been performed in dogs. METHODOLOGY/PRINCIPAL FINDINGS: Colonic mucosa samples were collected from six senior (12-year old) and six young adult (1-year old) female beagles fed one of two diets (animal protein-based vs. plant protein-based) for 12 months. Total RNA in colonic mucosa was extracted and hybridized to Affymetrix GeneChip® Canine Genome Arrays. Results indicated that the majority of gene expression changes were due to age (212 genes) rather than diet (66 genes). In particular, the colonic mucosa of senior dogs had increased expression of genes associated with cell proliferation, inflammation, stress response, and cellular metabolism, whereas the expression of genes associated with apoptosis and defensive mechanisms were decreased in senior vs. young adult dogs. No consistent diet-induced alterations in gene expression existed in both age groups, with the effects of diet being more pronounced in senior dogs than in young adult dogs. CONCLUSION: Our results provide molecular insight pertaining to the aged canine colon and its predisposition to dysfunction and disease. Therefore, our data may aid in future research pertaining to age-associated gastrointestinal physiological changes and highlight potential targets for dietary intervention to limit their progression.

Beta-mannan (β-mannan) is a polysaccharide composed of repeating units of mannose, galactose, and glucose. The increased amount of β-mannan is present in various plant protein sources such as soybean meal, palm kernel meal, copra meal, and guar meal. β-mannan is considered an antinutritional factor for non-ruminant animals. Endo-β-mannanase enzymes are endo-hydrolases that can cleave the internal glycosidic bonds of the mannan backbone. As a result, β-mannanase is used to break down β-mannan in animal feeds, thereby aiming to reduce its potential anti-nutritional effects. Previous research has demonstrated that dietary β-mannanase supplementation improves energy and nutrient utilization in broiler diets possibly by decreasing digesta viscosity in the gastrointestinal tract. However, results from previous studies have been inconsistent, mainly due to variable experimental conditions including animals, experimental design, and environment. Meta-analysis is a useful method to comprehensively evaluate and integrate various results from previous studies, thereby providing reliable and practical insights. Therefore, the objective of this study was to conduct the meta-analysis to evaluate the effect of dietary β-mannanase supplementation on digesta viscosity, and energy and nutrient utilization in diets for broiler chickens. Through an extensive literature search conducted on Scopus, PubMed, Web of Science, and Google Scholar between January 2003 and December 2023, we identified 10 eligible studies. The meta-analysis was performed using the “metafor” package in R software version 4.1.3. (R Core Team, 2023), and the standardized mean difference (SMD) and its 95% confidence interval (CI) were calculated using the random effect model. The results revealed that dietary β-mannanase supplementation increased apparent total tract retention (ATTR) of dry matter (SMD = 1.84; 95% CI: 0.46 to 3.21; P = 0.016), gross energy (SMD = 2.16; 95% CI: 1.19 to 3.12; P = 0.001), and nitrogen-corrected apparent metabolizable energy (AMEn ) in broiler diets (SMD = 3.38; 95% CI: 1.63 to 5.14; P = 0.002; Table 1). Moreover, dietary β-mannanase supplementation increased apparent ileal digestibility (AID) of gross energy (SMD = 6.65; 95% CI: 3.78 to 9.53; P = 0.002) and nitrogen (SMD = 1.41; 95% CI: 0.55 to 2.27; P = 0.006) in broiler diets (Figures 1 and 2). Finally, digesta viscosity (SMD = -3.35; 95% CI: -4.69 to -2.02; P < 0.001) in broiler chickens was decreased by dietary β-mannanase supplementation. In conclusion, the current meta-analysis indicates that dietary β-mannanase supplementation improves the overall utilization of energy and nutrients in diets with decreasing digesta viscosity in broiler chickens. [ABSTRACT FROM AUTHOR]

Beta-mannan (β-mannan) is commonly found in various feedstuffs and is well-recognized as an anti-nutritional factor for non-ruminant animals. In broiler chickens, dietary β-mannan is known to increase digesta viscosity, which is highly associated with decreased growth performance and intestinal health. Moreover, dietary β-mannan comprises surface components of various pathogens, which are recognized by innate immune systems, leading to an overstimulation of immune system. This over-expression of immune system by dietary β-mannan is likely considered the reason for decreased performance and health in broiler chickens. One potential solution to mitigate this antinutritional effect of dietary β-mannan is the supplementation of exogenous β-mannanase in broiler diets. Previous studies have demonstrated that dietary supplementation of β-mannanase improves growth performance, immune responses, and intestinal morphology in broiler chickens by improving nutrient digestion and absorption in the gastrointestinal tract. However, existing research on the effect of dietary supplementation of β-mannanase has shown highly variable results, possibly due to large variations in experimental designs such as number of animals, animal genotype, experimental locations, and rearing conditions. Therefore, to obtain a comprehensive understanding of previously reported various results regarding the effect of dietary β-mannanase, it is necessary to integrate them into quantitative analysis through meta-analysis. Subsequently, the objective of this study was to conduct a meta-analysis summarizing the outcomes of the effect of dietary β-mannanase on growth performance, immune organ weight, and intestinal morphology of broiler chickens. A total of 27 eligible studies were identified through a comprehensive literature search conducted on Scopus, PubMed, Web of Science, and Google Scholar between January 2003 and December 2023. The meta-analysis was performed with the package “metafor” of the R software version 4.1.3. (R Core Team, 2023), and the standardized mean difference (SMD) and its 95% confidence interval (CI) were calculated using the random effect model. The results indicated that dietary supplementation of [ABSTRACT FROM AUTHOR]

Poultry feeds primarily comprise plant ingredients such as cereal grains and cereal by-products that are high in non-starch polysaccharides (NSPs). However, poultry has limited digestive enzymes to efficiently utilize NSPs, and therefore, exogenous NSP-degrading enzymes (NSPase) are typically supplemented to poultry diets. Xylanase is the most widely used as NSPase in poultry diets because xylanase degrades arabinoxylans which is in increased amounts in most feed grains like corn and wheat, thereby improving dietary nutrient utilization and subsequent productive performance. β-glucanase is another potential exogenous NSPase used to degrade β-glucans present in plant ingredients. Although the benefits of dietary xylanase are well-documented, limited information regarding effects of dietary xylanase and β-glucanase complex is available. Therefore, this study aimed to investigate the effect of dietary supplementation of xylanase alone or combination of xylanase and β-glucanase on growth performance and intestinal measurements in broiler chickens. A total of four hundred 8-d-old male and female Ross 308 broiler chicks were randomly allotted to 1 of 4 dietary treatments with 10 replicates. Each replicate had 5 male and 5 female birds. Dietary treatments included a positive control (PC) diet with adequate energy and nutrients, a negative control (NC) diet with high NSPcontaining ingredients and less AMEn by 100 kcal/kg than PC diet, and 2 NC-based diets supplemented with 0.1% xylanase (4,000,000 units/kg) or 0.1% xylanase-glucanase complex (4,000,000 units/kg xylanase and 2,000,000 units/kg β-glucanase). The experiment lasted for 28 d. For intestinal measurements including jejunal morphology and ileal digesta viscosity, 1 male chicken per replicate was selected based on the body weight at the end of the experiment. Results indicated that birds fed PC diets had less (P < 0.05) FCR than those fed NC diets (Table 1). Birds fed diets supplemented with xylanase alone or combination of xylanase and β-glucanase had also less (P < 0.05) FCR than those fed NC diets. No difference in FCR was observed between birds fed PC diets and those fed diets supplemented with xylanase alone or combination of xylanase and β-glucanase. However, dietary treatments had no effects on body weight, body weight gain, and feed intake of broiler chickens. Jejunal villous height to crypt depth ratio (VH:CD) was greater (P < 0.05) for birds fed PC diets or diets supplemented with combination of xylanase and β-glucanase than those fed NC diets (Table 2). Feeding diets supplemented with xylanase alone or combination of xylanase and β-glucanase decreased (P < 0.05) ileal digesta viscosity as compared with feeding NC diets (Table3). In conclusion, feeding high NSP and low energy diets supplemented with either 0.1% xylanase alone or 0.1% xylanase and β-glucanase complex results in similar productive performance of broiler chickens as compared with feeding typical corn-soybean meal-based diets possibly due to improved intestinal structure and decreased digesta viscosity. [ABSTRACT FROM AUTHOR]

The objective of the current experiment was to investigate the effects of increasing glycine (Gly) equivalent in low crude protein (LCP) diets on growth performance in broiler chickens raised under multiple stress (MS) conditions. Ross 308 broiler chickens (n = 450; 22 d of age) were randomly allotted to 1 of 6 treatments with 6 replicates in a 2 × 3 factorial arrangement. The first factor included two different environmental conditions (normal condition vs. MS condition) and the second factor included three dietary treatments (CON, control diets; LCP, low crude protein diets; LCP+Gly, LCP diets with Gly supplementation). Birds in normal conditions were raised under recommended environmental conditions (22 ± 0.9°C and 53.6 ± 5.99 %) with low stock density (SD; 16.9 birds/m² ). Birds in MS conditions were exposed to a cyclic heat stress condition (32 ± 0.1°C for 8 h/d and 26°C ± 0.3°C for the remaining time) with high SD (25.3 birds/m² ). The average relative humidity was 37.9 ± 4.94%. In addition, 15 birds per cage were assigned in MS conditions to increase SD, whereas 10 birds per cage were assigned in normal conditions. The treatment diets included CON diets with adequate energy, crude protein (19.50% CP and 1.15% Gly equivalents), and other nutrients recommended for growing broiler chickens and LCP diets with low CP content (16.50% CP and 1.15% Gly equivalents) but adequate other nutrients. The LCP+Gly diets had increasing concentrations of Gly equivalents (17.19% CP and 1.73% Gly equivalents) by Gly supplementation to LCP diets. The diets and water were provided ad libitum throughout the experiment. Experiment lasted for 16 d from 22 d to 37 d of age. At the conclusion of the study, growth performance including body weight gain (BWG), feed intake (FI), and feed conversion ratio (FCR) was determined. All data were analyzed by 2-way ANOVA in a completely randomized design using the PROC MIXED procedure of SAS (SAS Institute Inc., Cary, NC). Results indicated that no interactions between environmental conditions and dietary treatments were observed for all growth performance measurements (Table 1). For the main effects, as expected, MS conditions decreased (P < 0.001) growth performance of broiler chickens, regardless of dietary treatments. The LCP diets increased (P < 0.05) FI and FCR as compared with CON diets, regardless of environmental conditions. However, LCP+Gly diets decreased FI (P < 0.05) and tended to decrease FCR (P = 0.076) as compared with LCP diets. In conclusion, either MS conditions or LCP diets impair growth performance in broiler chickens with no significant interaction. However, increasing Gly equivalents by Gly supplementation to LCP diets are likely to improve feed efficiency in broiler chickens regardless of stress environments. [ABSTRACT FROM AUTHOR]