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A 1932 editorial in Poultry Science stated that sampling theory, or experimental power, could be useful for "the investigator to know how many … birds to put into each experimental pen." Nevertheless, in the past 90 yr, appropriate experimental power estimates have rarely been applied to research with poultry. To estimate the overall variation and appropriate use of resources with animals in pens, a nested analysis should be conducted. Bird-to-bird and separate pen-to-pen variances were separated for 2 datasets, one from Australia and one from North America. The implications of using variances for birds per pen and pens per treatments are detailed. With 5 pens per treatment, increasing birds per pen from 2 to 4 decreased the SD from 183 to 154, but increasing birds/pen from 100 to 200 only decreased the SD from 70 to 60. With 15 birds per treatment, increasing pens/treatment from 2 to 3 decreased SD from 140 to 126, but increasing pens/treatment from 11 to 12 only decreased the SD from 91 to 89. Choosing the number of birds to include in any study should be based on expectations from historical data and the amount of risk investigators are prepared to accept. Too little replication will not allow relatively small differences to be detected. On the other hand, too much replication is wasteful in terms of birds and resources, and violates the fundamental principles of the ethical use of animals in research. Two general conclusions can be made from this analysis. First, it is very difficult to detect 1% to 3% differences in broiler chicken body weight with only one experiment consistently because of inherent genetic variability. Second, increasing either birds per pen or pens per treatment decreased the SD in a diminishing returns fashion. The example presented here is body weight, of primary importance to production agriculture, but it is applicable whenever a nested design is used (multiple samples from the same bird or tissue, etc.)., (Copyright © 2023. Published by Elsevier Inc.)

Re-emergence of enteric diseases in the postantibiotic era has imposed severe loss to the poultry industry leading to the urgent need for appropriate additives to maintain gut health. Recently, more attention has been paid to animal plasma due to its high concentrations of active components such as albumins and globulins. The objective of this study was to evaluate the effects of spray-dried porcine plasma (SDP) supplementation during the starter phase (d 0-10) on growth performance, intestine health, and immune response of broilers under necrotic enteritis (NE) challenge. A total of 720 day-old male broiler parental line chicks (Ross 308) were randomly assigned to a 2 (NE challenge: no, yes) × 2 (SDP: 0, 2%) factorial arrangement with 12 replications of 15 chicks each. To induce NE, birds were inoculated with live Eimeria vaccine on d 9 and Clostridium perfringens on d 14. The body weight of birds and feed consumption were measured per pen on d 8, 10, 24, and 29 to calculate performance parameters. On d 16, three birds per pen were sampled to analyse the intestinal lesion score, gut permeability, villi morphology, relative weight of organs, and immune response. Results showed that SDP improved (P < 0.001) FCR in the pre-challenge phase (d 0-8). The results indicated that supplementing SDP lowered (P < 0.01) FCR at the end of the experiment (d 29). Dietary SDP decreased (P < 0.05) the concentration of FITC-d in serum samples of challenged broilers, although it did not affect the intestinal morphology and lesion score. Birds fed with SDP had a higher (P < 0.05) relative weight of bursa (g/kg live body weight) compared to non-supplemented birds. Supplementing SDP reduced the concentration of interleukin-6 (P < 0.05) and α-1 acid glycoprotein (P = 0.051) in serum samples of broilers. In conclusion, supplementation of SDP in the starter phase enhanced feed efficiency and gut integrity in NE challenged broilers, possibly through manipulating the immune response, while further studies targeting intestinal microflora and key genes are required to explore the mode of action., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

The aim of this study was to evaluate the importance of considering dietary soluble non-starch polysaccharides (sNSP) when formulating broiler diets, due to their impact on the gastrointestinal tract environment. Cobb 500 broilers (n = 480, 80 birds per treatment) were fed either wheat- or corn-soybean meal-based diets formulated to contain either a high, medium or low sNSP content, resulting in 6 dietary treatments in a 2 × 3 factorial arrangement of treatments. On d14 and d 35 of age, pH of the gizzard, ileum and caeca, ileum viscosity, caecal short chain fatty acid (SCFA) concentration, and ileal and caecal microbiota profile were determined. Ileal viscosity at d 35 was greater in birds fed high sNSP compared to low sNSP (P = 0.022). At both d 14 and d 35, birds fed the wheat-based diet presented higher ileal viscosity (P < 0.001) and lower ileal pH (P = 0.027 and P < 0.001, respectively) compared to those fed the corn-based diet. At d 14, birds fed low sNSP exhibited higher caecal pH (P = 0.010) and propionic, isobutyric and valeric acid concentrations (P = 0.035, P = 0.007 and P = 0.011, respectively), and lower ileal Lactobacillus content (P = 0.043), compared to birds fed high sNSP. This effect was also seen for total SCFA (P = 0.017) and acetic acid (P = 0.005) concentrations in the caeca at d 14, but only in birds fed wheat-, not corn-, based diets. At d 35, total caecal SCFA concentration was greater in birds fed the wheat-based diet with high sNSP level compared to those fed the corn-based diet with high or low sNSP level (P = 0.028). In comparison to birds fed corn, birds fed wheat presented greater caecal concentrations of acetic, butyric, lactic, and succinic acids (P = 0.001, P < 0.001, P = 0.003 and P = 0.007, respectively) and Bifidobacteria at d 35 (P = 0.003) and succinic acid at d14 (P = 0.041). However, caecal populations of Ruminococcus and concentrations of valeric acid at d14 and isobutyric acid at d 35 were greater in birds fed the corn- compared to wheat-based diets (P = 0.043, P = 0.019 and P < 0.001, respectively). These results illustrate that dietary sNSP concentration, as well as its composition, have a direct impact on gastrointestinal viscosity and pH, and fuel beneficial microbial species, resulting in production of SCFA. It appears to be particularly important to consider sNSP level when formulating wheat-based diets for broilers., (Crown Copyright © 2021. Published by Elsevier Inc. All rights reserved.)

This study was conducted to investigate the effects of zinc (Zn), as a combination of oxide (ZnO) and sulfate (ZnSO 4 ), compared with incremental levels of zinc hydroxychloride (ZH) on tibia traits, intestinal integrity, expression of selected jejunal genes, cecal short chain fatty acids and microbial composition in broilers. Day-old male Ross 308 chicks (n = 784) were randomly allocated to seven dietary treatments, each replicated seven times with 16 chicks per replication. The dietary treatments included a negative control diet (NC) with no supplemental Zn, a positive control (PC) with 100 mg/kg supplemental Zn from an ionic bound source combination (50 mg/kg ZnO + 50 mg/kg ZnSO 4 ), and the NC diet supplemented with one of 20, 40, 60, 80, or 100 mg/kg Zn as ZH. The diets were fed over starter (1-14 d) and grower (14-35 d) phases, with tissue and digesta samples collected from 3 birds per replicate on days 14 and 35. The results showed that dietary Zn level had a significant effect on tibia breaking strength on d 35 (P < 0.05), and tibia Zn concentration both on d 14 and d 35 (P < 0.01). Dietary Zn levels linearly (P < 0.01) increased cecal lactic acid production, increased Lactobacillus, and decreased Bacillus and total bacteria counts (P < 0.05). Inclusion of 80 and 100 mg/kg Zn as ZH tended to upregulate the expression of claudin-1 (P = 0.088) and tight junction protein-1 (P = 0.086). The results obtained in this study suggest that a non-Zn supplemented diet can negatively influence tibia development and gut microbiota composition in broiler chickens. Higher supplemental Zn in the diet alters cecal microbiota population in favor of Lactobacillus and can decrease the total bacterial load. Supplemental Zn level in the feed have the potential to manipulate the jejunal gut integrity at a molecular level., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

The study investigated the benefit of a Bacillus subtilis probiotic (Bs 29,784) in necrotic enteritis (NE)-challenged broilers. Four treatments were performed with 312 male day-old Ross 308 reared in floor pens from day 0 to day 35: 2 groups fed control diet without or with NE challenge (CtrlNC and CtrlNE); 2 groups fed probiotic and antibiotic supplements in the control diet with NE challenge (ProNE and AntNE). Necrotic enteritis challenge procedures commenced with inoculation of Eimeria spp 1 mL/bird per os at day 9 and Clostridium perfringens EHE-NE18 (approximately 10 8  cfu/mL) 1 mL/bird per os at day 14 and day 15. Performance parameters were measured on day 16 and day 35. Lesion, cecal microbiota, and jejunal gene expression were analyzed on day 16. Necrotic enteritis challenge significantly suppressed the performance parameters compared with CtrlNC: 27% weight gain reduction, 11 points feed conversion ratio (FCR) increase at day 16, and 12% weight gain reduction, 5-point FCR increase at day 35. By day 35, ProNE and AntNE treatments enabled significantly higher weight gain (4 and 9%, respectively) than CtrlNE. Compared with CtlrNE and contrary to AntNE, ProNE treatment exhibited upregulation of genes coding for tight junctions proteins (CLDN1, JAM2, TJP1), cytokines (IL12, interferon gamma, TGFβ), and Toll-like receptors (TLR5, TLR21) suggesting enhanced immunity and intestinal integrity. 16S NGS analysis of cecal microbiota at day 16 showed a decreased alpha diversity in challenged groups. Principal component analysis of operational taxonomic unit (OTU) abundance revealed that ProNE and AntNE grouped closely while both distantly from CtrlNC and CtrlNE, which were separately grouped, indicating the similar effects of ProNE and AntNE on the OTU diversity that were however different from both CtrlNC and CtrlNE. Microbiota analysis revealed an increase of genera Faecalibacterium, Oscillospira, and Butyricicoccus; and a decrease of genera Ruminococcus, Lactobacillus, and Bacteroides; and an increase of the Firmicutes-to-Bacteroidetes ratio in ProNE and AntNE groups compared with the CtlrNE group. It is concluded that Bs 29,784 may enable improved health of broiler chickens under NE conditions thus performance implications., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Identification of sex in broiler chickens allows researchers to reduce the level of variation in an experiment caused by the sex effect. Broiler breeds commonly used in research are no longer feather sexable because of the change in their genetics. Other alternate sexing methods are costly and difficult to apply on a large scale. Therefore, a sexing method is required that is both cost effective and highly sensitive as well as having the ability to offer high throughput genotyping. In this study, high-resolution melting (HRM) analysis was used to detect DNA variations present in the gene chromodomain helicase DNA binding 1 protein (CHD1) on the Z and W chromosomes (CHD1Z and CHD1W, respectively) of chickens. In addition, a simplified DNA extraction protocol, which made use of the basal part of chicken feathers, was developed to speed up the sexing procedure. Three pairs of primers, that is, CHD1UNEHRM1F/R, CHD1UNEHRM2F/R, and CHD1UNEHRM3F/R, flanking the polymorphic regions between CHD1Z and CHD1W were used to differentiate male and female chickens via distinct melting curves, typical of homozygous or heterozygous genotypes. The assay was validated by the HRM-sexing of 1,318 broiler chicks and verified by examining the sex of the birds after dissection. This method allows for the sexing of birds within a couple of days, which makes it applicable for use on a large scale such as in nutritional experiments., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

Undigested proteins entering the hindgut may favor the proliferation of Clostridium perfringens. Using phytase to eliminate the need for meat and bone meal (MBM) as a P source may reduce potential infection with C. perfringens. A study was conducted to determine the impact of MBM, phytase, and antibiotics (AB) on intestinal permeability and morphology, organ weights, and jejunal gene expression in Ross 308 chickens challenged with subclinical necrotic enteritis (NE). Male Ross 308-day-old chicks (672 each) were randomly allocated to 8 treatments with 6 replicate pens each housing 14 birds. A 2 × 2 × 2 factorial arrangement of treatments was used: MBM (no or yes); AB (no or yes-Zn bacitracin 100 in S and 50 ppm in G/F and salinomycin Na 60 ppm in all phases); phytase (500 or 1,500 FTU/kg, both using 500 FTU matrix values) using wheat-SBM-canola meal diets. Birds were challenged with Eimeria spp on day 9, and C. perfringens strain EHE-NE18 on day 14 and 15. An AB × MBM interaction (P < 0.05) was detected for relative gizzard weight (with contents) being lower in birds fed MBM and AB compared to those fed MBM and no AB. A MBM × AB interaction (P > 0.01) was detected for lymphocyte counts being lower with MBM and AB compared to MBM without AB. A phytase × AB interaction (P < 0.05) was observed for villi length being increased with high phytase and no AB compared to with AB. Inclusion of MBM increased (P < 0.05) blood FICT-d concentration, whereas AB decreased it (P < 0.05). Antibiotics increased RBC (P < 0.05), Hgb (P < 0.05), and PCV (P < 0.05) and expression of Ca-binding protein, CALB1 (P > 0.05). Inclusion of MBM decreased expression of MUC2 (P < 0.05). Results indicate that dietary MBM has a detrimental effect on gut health of broilers but this may be counteracted using AB., (Copyright © 2020. Published by Elsevier Inc.)

Necrotic enteritis (NE) is an infection of the gastrointestinal tract and is estimated to cost the global poultry industry billions of dollars annually. A study was conducted to examine whether reducing the crude protein might offset the severity of NE in broilers experimentally challenged with Eimeria spp. on day 9 and Clostridium perfringens on days 14 and 15. Furthermore, increasing the dietary amino acid (AA) density of the diet was also examined owing to identified benefits of improving performance compromised from low protein (LP) diets or NE. A 2 × 2 × 3 factorial arrangement of treatments at 6 replicates per treatment was used with 972 Ross 308 cockerels fed wheat-sorghum-soy-based diets to 35 D. Factors were NE challenge: no or yes; protein: standard (SP) or LP; and AA density: 100% AA, 115% with only essential AA (115% EAA) increased, and 115% AA with both essential and nonessential AA (115% AA) increased. The performance was measured in grower (days 7-21), finisher (days 21-35), and overall (day 7-35) periods. In addition, on day 16, intestinal lesion score and cecal short-chain fatty acids were measured. Only in nonchallenged birds fed LP diets, 115% AA increased grower feed intake (P < 0.01) and body weight gain (P < 0.05) compared to 115% EAA treatments. Challenge increased jejunal lesions (P < 0.001) with no difference between dietary treatments. Finisher body weight gain was greater in nonchallenged birds fed the 115% AA diets than in challenged birds (P < 0.05). Feeding diets with higher nonessential AA encouraged faster recovery from NE challenge. When fed the SP diets, NE challenge increased cecal butyric acid (P < 0.01) and total short-chain fatty acids (P < 0.05). The nutrient matrix used in LP diets does not favor beneficial butyric acid-producing bacteria. Using LP diets to mitigate NE severity does not offset the predisposing effect of E. spp. when attacking the gastrointestinal tract, and NE recovery is favored when feeding SP diets or additional AA., (Copyright © 2019. Published by Elsevier Inc.)

This study investigated the influence of meat and bone meal (MBM), phytase, and antibiotics (AB) on the performance, intestinal pH, ileal digestibility, cecal microbiota, and tibial mineralization in Ross 308 broilers challenged with necrotic enteritis (NE). A total of 672-day-old male Ross 308 chicks were allocated to 8 treatments with 6 replicate pens, with 14 birds each. The study employed a 2 × 2 × 2 factorial arrangement of treatments: MBM (no or yes), AB (no or yes, zinc bacitracin + salinomycin), and phytase level (500 or 1,500 FTU/kg; both using 500 matrix recommendations). Diets were based on wheat-soybean meal-canola meal. All birds were challenged with Eimeria spp on day 9 and Clostridium perfringens (C. perfringens) strain EHE-NE18 on day 14 and day 15. On day 21 (postchallenge), birds fed MBM had reduced weight gain (WG; P < 0.05) relative to without MBM. A 2-way phytase × AB interaction for WG on day 14 (P < 0.001) and day 21 (P < 0.001) and feed conversion ratio on day 21 (P < 0.001) and day 42 (P < 0.01) indicated positive effects of high phytase on bird performance in the presence of AB. On day 42, a 3-way MBM × phytase × AB interaction (P < 0.01) was observed for WG, showing high phytase increased WG with AB, relative to the birds without AB in the presence of MBM. A 2-way MBM × phytase interaction (P < 0.01) was observed for apparent ileal digestibility of Ca and P on day 16, whereby there was a notable reduction in Ca and P digestibility in birds fed MBM-free diets and a low phytase level, but with the high phytase level, Ca and P digestibility was not influenced by MBM. In conclusion, in NE challenged birds, high phytase has a beneficial effect on leg health and mineral utilization to the extent that it can replace MBM and has beneficial effects on bird performance in the presence of AB., (Copyright © 2019. Published by Elsevier Inc.)

Reducing dietary CP can reduce N pollution. Much research has been reported in corn-based diets; however, the amino acid (AA) profiles of wheat-based diets differ. Poor performance as a result of reduced protein (RP) has been overcome in corn-based diets with essential AA and glycine (Gly) supplementation. The current study examined RP levels and Gly in wheat-based diets. An industry standard protein (SP) diet plus 3 RP diets with and without Gly supplementation, to match the SP treatment at 0.713 and 0.648% digestible Gly for the grower and finisher periods respectively, were fed to male broilers from day 10 of age. Grower CP included 22.5, 20.6, 18.3, and 17.7% (days 10-21) and finisher CP included 19.7, 17.8, 16.2, and 15.5% (days 21-35). Performance, meat yield, N efficiency, water intake, and apparent ileal digestibility of N and AA were measured. No difference in body weight gain (BWG), feed intake, or feed conversion ratio (FCR) were observed at 20% CP compared to the SP treatment. However, further reducing protein reduced BWG (P < 0.001), feed intake (P < 0.001), and increased FCR (P < 0.001). Supplementation of 0.713% Gly in the grower period increased BWG (P < 0.001) and reduced FCR (P < 0.001). Relative meat yield was not affected by dietary protein, however reducing CP increased relative fat pad weight (P < 0.001). Nitrogen efficiency increased with decreased CP in both grower (R 2 = 0.69) and finisher (R 2 = 0.80) treatments. Water intake decreased (R 2 = 0.83) with decreasing CP intake. Apparent ileal digestibility of AA and N were higher in RP diets (P < 0.05). The benefits of reduced water intake and increased N efficiency and the disadvantages of poor performance and increased body fat in RP corn-based diets have been identified in RP wheat-based diets. Furthermore, at 18.5% CP the supplementation of crystalline AA and Gly can maintain BWG and FCR observed in SP diets., (Copyright © 2019. Published by Elsevier Inc.)

Subclinical necrotic enteritis (NE) is primarily caused by the gram-positive bacterium, Clostridium perfringens (Cp). The trend towards removal of in-feed antimicrobials and subsequent increased emergence of infection in poultry has resulted in a wide interest in better understanding of the mechanism behind this disease. The virulence of NE, to a large extent, depends on the virulence of Cp strains. Thus, this study was to assess how 2 different strains of Cp affect performance and gut characteristics of broiler chickens. Ross 308 male broilers (n = 468) were assigned to a 2 × 3 factorial arrangement of treatments with antibiotics (Salinomycin at 72 ppm and zinc bacitracin at 50 ppm -, or +) and challenge (non-challenge, Cp EHE-NE18, or Cp WER-NE36). Oral administration of Eimeria oocysts (day 9) followed by inoculation with 1 mL 108 CFU Cp strains (day 14 and 15) were used to induce NE. Broiler performance was analyzed at day 10, 24, and 35. On day 16, intestinal lesion score and intestinal pH were evaluated and samples of cecal content were analyzed for bacterial counts and short-chain fatty acid concentrations (SCFA). Birds in both challenged groups showed higher feed conversion ratio (FCR), lower weight gain (P < 0.001), increased lesion scores in the jejunum (P < 0.01), and reduced pH in the ileum and cecum (P < 0.01), compared to the non-challenged birds. They also showed decreased numbers of Bacillus spp. (P < 0.001), and Ruminococcus spp. (P < 0.01) in the cecal content. On day 35, the NE36 challenged birds had a lower weight gain (P < 0.001) and higher FCR (P < 0.001) compared to the NE18 challenged birds. Interestingly, cecal Lactobacillus and lactate were increased by the NE challenge (P < 0.001), and to a greater extent in birds challenged with NE36 compared to the NE18 strain (P < 0.001). This study suggests that Cp strains varying in virulence produce different levels of disease in broiler chickens through modulating the gut environment, intestinal microbiota, and SCFA profile to different extents., (© 2019 Poultry Science Association Inc.)

Using accurate nutrient values for ingredients is of vital importance for efficient diet formulation. The net energy (NE) system accounts for the real available amount of feedstuff energy for body maintenance and production as it considers energy dissipated as heat increment. The NE content of diets for pigs and broilers has been estimated from their nutrient contents. However, such estimates have not been made specifically for laying hens. This study reports the development of equations to predict NE for laying hens based on the chemical composition of 16 different diets meeting minimum nutrient specifications but varying in nutrient composition. Heat production and energy metabolism were measured in layers ranging from 32 to 62 weeks of age in closed-circuit calorimetry chambers with 8 replicates per diet in a randomized design. Each replicate consisted of a chamber with 3 layers that were adapted for 4 D to diets and chambers prior to measurement. The measurements included feed intake, metabolizable energy (ME) content, nitrogen balance, egg production, gas exchange, heat production, energy efficiency, and energy partition for a 3-D period. The average AME/GE and NE/AME ratios of the 16 diets were 77 and 74%, respectively. The latter ratio increased with energy efficiency (EE) content and decreased with CP content of diets. The results indicate that diet NE content can be predicted from AME, CP, and EE contents and the NE/AME ratio varied positively with EE and negatively with CP. A validation experiment with 2 diets fed to layers in calorimetry chambers confirmed the estimation from NE prediction equations. In conclusion, NE of diets can be predicted in laying hens from equations based on AME and CP and EE contents in laying hens being similar to those reported in broilers., (© 2019 Poultry Science Association Inc.)

A total of 90 male Ross 308 broiler chicks were used in a digestibility and performance bioassay to explore the effect of reduction in dietary protein and digestible amino acids and inclusion of an exogenous mono-component protease on amino acid digestibility, net energy, jejunal gene expression, and bird performance. Four dietary treatments were created by the supplementation, or not, of 2 control diets with a mono-component exogenous protease. The control diets were corn/wheat/soybean meal-based and were formulated to be either nutritionally adequate or reduced in protein and amino acids (around 3%). The 2 control diets were supplemented with xylanase and phytase (2000 FYT). Treatments were therefore arranged as a 2 × 2 factorial design. The reduction in diet nutrient density had no significant effect on various experimental outcomes (including bird performance, amino acid digestibility, and net energy [NE]) that were measured with the exception of a reduction in the expression of aminopeptidase N and glucose transporter 2. However, the addition of exogenous protease resulted in an increase in weight gain and a reduction in feed conversion ratio (around 4%; P < 0.05) and an increase in the digestibility of several amino acids (P < 0.05) and starch (P = 0.06). Protease addition also resulted in an increase in both apparent metabolizable energy (AME) (+73 kcal/kg; P < 0.05) and NE (+107 kcal/kg; P < 0.05). The addition of exogenous protease to the diet also increased the jejunal expression of genes responsible for peptide transport (PepT2; P < 0.01) and starch digestion (sucrase isomaltase; P = 0.06). These results confirm the efficacy of exogenous protease in broiler diets that contain both xylanase and phytase and suggest substantial beneficial effects that extend beyond protein and amino acid nutrition. The effect of exogenous protease on energy partitioning, starch digestibility and the efficiency of nitrogen cycling is an area for further study., (© The Author(s) 2018. Published by Oxford University Press on behalf of Poultry Science Association.)

Necrotic enteritis (NE) causes significant economic losses in the broiler chicken industry, especially in birds raised without in-feed antibiotics. L-glutamine (Gln) is an amino acid that may compensate for metabolic losses from infection and improve the intestinal development. This study investigated the effects of dietary Gln (10 g/kg) supplementation on growth performance, intestinal lesions, jejunum morphology, and serum biochemical indices of broiler chickens during NE challenge. The study employed a factorial arrangement of treatments with factors: NE challenge, no or yes; dietary Gln inclusion, 0 g/kg in starter (S), d 0 to 10, grower (G) d 10 to 24, and finisher (F) d 24 to 35; 10 g/kg in S, G, F, or 10 g/kg in S, G only. Each treatment was replicated in 6 floor pens with 17 birds per pen as the experimental unit for performance and 2 birds for other measurements. Challenge significantly reduced bird performance, increased incidence of intestinal lesions, and affected intestinal development and serum biochemical indices. Regardless of challenge, Gln supplementation increased gain (P < 0.05), feed intake (P < 0.05), and decreased FCR (P < 0.05) on d 24. On d 35, Gln improved gain (P < 0.05) and FCR (P < 0.001) whereas withdrawing Gln from finisher tended to diminish the beneficial effect on weight gain but not FCR. Dietary Gln reduced lesion scores in the jejunum (P < 0.01) and ileum (P < 0.01) in challenged birds. On d 16, Gln increased villus height to crypt depth ratio in unchallenged birds (P < 0.05) and reduced crypt depth of challenged birds on d 24 (P < 0.05). Regardless of challenge, supplementation with Gln reduced crypt depth on d 16 (P < 0.05), and increased villus height (P < 0.01) and the villus height to crypt depth ratio (P < 0.001) on d 24. Dietary Gln lowered serum uric acid level regardless of challenge (P < 0.05). The current study indicates that dietary Gln alleviates adverse effects of NE and may be useful in antibiotic-free diets.

Improving diet digestibility is important to the broiler industry. Therefore, this study focused on optimizing the physical structure of feed ingredients and addition of dietary fiber as strategies to improve nutrient digestibility in low and high sodium diets. A total of 672 day-old Ross 308 male broilers was allocated to 48 pens using a 2 × 2 × 2 factorial arrangement of treatments with 2 particle sizes of corn (coarse 3,576 μm or fine 1,113 μm geometric mean diameter), 2 levels of sugarcane bagasse (SB) (0 or 2%), and 2 levels of Na (0.16 or 0.4%). Protein digestibility coefficient was measured using pooled distal ileal digesta of 3 birds per pen on d 24. Meanwhile, starch and gross energy digestibility coefficients were measured using pooled duodenal, distal jejunal, and distal ileal digesta of 3 birds per pen on d 24. Coarsely ground corn (CC) resulted in improved ileal protein digestibility (P < 0.05). Addition of 2% SB increased starch digestibility in the duodenum (P < 0.05), distal jejunum (P < 0.001), and distal ileum (P < 0.001), and increased protein digestibility in distal ileum (P < 0.01). A significant particle size × SB × Na interaction was observed for ileal energy digestibility (P < 0.05). The SB increased ileal energy digestibility only in birds fed the diet with finely ground corn (FC) and 0.16% Na. These findings demonstrate that SB and CC are able to improve nutrient digestibility. It can be recommended for the poultry industry to use SB and coarsely ground corn in feed to improve the utilization of nutrients.

Necrotic enteritis (NE) causes significant economic losses in the broiler chicken industry, especially in birds raised without in-feed antibiotics. A standardized blend of plant-derived isoquinoline alkaloids (IQA) derived from Macleaya cordata has shown to have anti-inflammatory potency and promoted animal productivity. This study investigated the effects of IQA supplementation on broiler chickens under NE challenge. A 2 × 2 factorial arrangement of treatments was employed with factors: NE challenge (no or yes), and additives (no additive or IQA at 0.15 g/kg) in starter, grower, and finisher diets. Birds were challenged with Eimeria spp. on d 9 and 108 to 109Clostridium perfringens on d 14. Each treatment had 7 replicate floor pens with 17 birds each. NE challenge negatively affected growth performance, livability, and carcass traits. Regardless of challenge, IQA increased feed intake and gain on d 24 (P < 0.05) and 35 (P < 0.01) and improved FCR (P < 0.05), flock uniformity (P < 0.01) and breast meat yield (P < 0.001) on d 35. Supplementation of IQA also reduced lesions in the duodenum (P < 0.05), jejunum (P < 0.001), and ileum (P < 0.001). This study suggests that IQA may protect broilers from NE indicating its role as a promising antibiotic alternative., (© 2017 Poultry Science Association Inc.)

Two broiler chicken experiments were conducted to investigate the effects of canola meal (CM) replacing soybean meal (SBM) in diets supplemented with carbohydrase and protease on performance and partitioning of energy. First, a 2 × 2 × 2 factorial arrangement of treatments was employed to evaluate: protein meals (CM vs. SBM), carbohydrase (none or 300 mg/kg), protease (none or 200 mg/kg), and their interactions. Each treatment was fed to 6 replicated pens of 16 male broilers (Ross 308) from d 10 to 35. In the second experiment, 32 broiler chicks were used in a 2 × 2 factorial arrangement to investigate CM and carbohydrase effects on energy partitioning. Birds were transferred into 16 closed-circuit calorimeter chambers (4 chambers/diet; 2 birds/chamber) to measure heat production (HP), metabolizable and net energy (NE) by gaseous exchange, and total excreta collection from d 25 to 28. There were no 3-way interactions among experimental factors for any of the performance parameters measured. Birds given CM diets consumed less feed, had lower BW, and exhibited higher FCR compared to the control birds (P < 0.01). Both enzymes, alone or in combination, improved final BW and FCR (P < 0.05). There was an interaction between carbohydrase and protease for FCR over the grower period (P < 0.01), in which the combination of the enzymes resulted in further improvement of FCR. Energy, DM, and crude protein digestibility values were higher in control birds (P < 0.05). There was an interaction of protein meal and carbohydrase for HP, respiratory quotient (P < 0.05), and NE:ME ratio of the diets (P = 0.06). Inclusion of CM without carbohydrase increased HP and decreased NE and NE:ME ratio of the diets (P < 0.05). Carbohydrase decreased HP and increased retained energy (P = 0.06) and NE and NE:ME ratio (P < 0.05). In conclusion, high CM in the diet negatively affects growth performance through reduction in feed consumption, nutrient digestibility, and NE of the diet, which could partly be restored by enzyme supplementation., (© 2017 Poultry Science Association Inc.)

Broiler chickens are commonly placed on wood shavings as litter, but alternative litter sources are required due to the scarcity of wood shavings in many parts of the world. This study aimed to compare pelleted straw, chopped wheat straw, wood shavings, rice hulls, and shredded paper as litter candidates. Three-hundred-sixty Ross 308 one-day-old male chicks were used in this study. There were 5 litter treatments with 6 replicate pens, each with 12 birds. The feed conversion ratio (FCR) of birds reared on pelleted straw was improved compared (P < 0.05) to that of birds raised on rice hulls, whereas it did not differ for birds placed on wood shavings, rice hulls, chopped straw, or shredded paper. It was observed that the birds reared on wood shavings had higher relative gizzard weight at d 24 compared to those reared on pelleted straw (P < 0.05). Gizzard pH and measured cecal bacterial groups were not affected by the type of bedding material. Cecal bacterial groups measured at d 10 were not affected by bedding material. Birds reared on pelleted wheat straw had a lower incidence of footpad lesions than those on chopped straw and shredded paper on d 24 (P < 0.001) and 29 (P < 0.01). Litter source did not affect the occurrence of breast blisters at d 24, 29, or 35. On d 24, 29, and 35, pelleted straw litter was less caked than chopped straw and shredded paper (P < 0.001) whereas no significant differences were observed among pelleted straw, wood shavings, and rice hulls. The study demonstrated the potential benefits to using pelleted wheat straw as a bedding material. Further assessment of pelleting of wheat straw and other materials on broiler health, performance, and welfare are needed to determine the economic benefits of pelleted litter., (© 2017 Poultry Science Association Inc.)

A pair-feeding study was conducted to determine if reduced feed intake (FI) in broiler chickens fed high canola meal (CM) diets per se accounts for reduced growth performance and whether this lower growth rate can be mitigated by increasing dietary amino acid (AA) levels. Five experimental wheat-based diets were formulated as follows: soybean meal (SBM) diet, high CM diet with normal AA concentration, and high CM diets with 3, 6, or 9% additional AA concentration (Lys, Met+Cys, Thr, Ile, Arg, and Val). Another group of birds was pair-fed with SBM diet to the consumption levels of birds fed CM diet with normal AA. There were 6 replicates of 17 male 10-day-old Ross 308 chicks per treatment over grower and finisher periods. Birds fed the CM diets had reduced FI and BWG, but improved FCR (P < 0.01) compared to SBM ad libitum fed birds. The SBM pair-fed birds gained the same weight and exhibited similar FCR compared to CM fed birds. Additional 9% AA improved FCR (P < 0.01) compared to SBM and CM diets with normal AA. No significant differences were observed in ileal digestibility of DM, energy, crude protein, and AA between CM with normal AA and SBM diets. The additional 6 and 9% AA in CM diets increased digestibility of crude protein and some AA (P < 0.05). SBM ad libitum and CM + 6 and 9% AA fed birds had the highest and lowest relative weight of abdominal fat, respectively (P < 0.05). Addition of 6 and 9% AA in CM diets increased relative carcass and breast yields (P < 0.01). Serum triglyceride level was higher in SBM ad libitum fed birds (P < 0.05). The composition of microbiota in the ceca was not affected by treatments. This study showed that reduced growth of birds fed high CM diets is primarily mediated through reduced FI. This growth depression could partially be ameliorated by increasing dietary AA levels., (© 2016 Poultry Science Association Inc.)

The net energy (NE) value may be a better measure than apparent metabolizable energy (ME) of the effect of supplemental phytase on energy utilization in broilers. The present study was conducted to assess the impact of 3 microbial phytases supplemented at an unconventionally high level (1,000 FTU/kg feed) on performance and NE of broilers using the indirect calorimetric method (IC). Four treatments included: 1) Control, formulated to be deficient in ME (12.35 MJ/kg in the starter diet; 12.56 MJ/kg in the grower diet), calcium (0.72% in the starter diet; 0.60% in the grower diet), and available phosphorus (0.25% in the starter diet; 0.20% in the grower diet); 2) control + intrinsically thermostable phytase A; 3) control + intrinsically thermostable phytase B; and 4) control + coated phytase C. A completely randomized design was employed. A total of 384 male broiler chicks were used, and each treatment had 6 replicates with 16 birds per replicate. The birds were reared until d 21 in floor pens with hardwood shavings. Thirty-two birds (8 birds per treatment) were randomly selected to determine heat production and NE (from 25-28 d) following a 3-d acclimatization in the respiratory chambers. Performance results at d 21 showed that supplementation with either of the 3 phytases improved body weight (P < 0.001) and feed intake (P < 0.05), and increased the relative weights of tibia ash (P < 0.05) and toe ash (P < 0.01). Phytases A and B increased the NE value of the diet (P < 0.05). It may be concluded that the negative effects imposed by calcium and available phosphorus down-specification can be compensated by phytase supplementation in general, and intrinsically thermostable phytases improve the ME and NE value. However, phytase did not reduce heat production, heat increment, or increase NE:ME in birds., (© 2015 Poultry Science Association Inc.)

There is generally no information regarding the influence of distillers dried grains with solubles (DDGS) on the net energy (NE) value of broiler diets. It was hypothesized that the ME content of DDGS may overestimate its productive energy, leading to higher heat increment when used in broiler diets. Furthermore, it was of interest to investigate the potential benefits of a mixture of carbohydrases and protease on energy partitioning in diets containing DDGS. In this study, 2 evaluations, comparative slaughter (CS) or indirect calorimetry (IC), were conducted using the same batch of birds and feed. Two levels of DDGS (0 or 30%) without or with an enzyme mixture were used in a 2 × 2 factorial arrangement of treatments. The CS evaluation used 240 male Ross 308 broiler chicks with 6 replicates (10 birds each) per treatment from d 18 to 28. Carcass energy values were examined in 2 birds per replicate on each of d 18 and 28 to determine heat production (HP), NE, and ME. The IC evaluation used 32 birds acclimatized to 16 closed-circuit calorimeters (2 birds per chamber) following energy partitioning measurement by gaseous exchange and total excreta collection from 18 to 24 d. Birds fed DDGS had increased feed efficiency during starter and grower phases (P < 0.001). The CS showed no difference in HP between birds fed diets with or without DDGS. When measured by IC, birds fed diets containing DDGS had higher HP and lower NE (P < 0.01). Enzyme supplementation had no effect on HP, ME, or NE:ME ratio measured using CS or IC but increased NE and NE intake (P < 0.01) from d 18 to 28. Carcass fat retention was decreased (P < 0.05) and there was a lower NE (P < 0.01) in birds fed the DDGS-diets. This study showed that 30% dietary DDGS affects energy partitioning in broilers with more heat produced, decreased dietary NE, and less fat retained in the carcass., (©2014 Poultry Science Association Inc.)

Excessive accumulation of lipids in the adipose tissue is one of the main problems faced by the broiler industry nowadays. In chicken, lipogenesis occurs essentially in the liver, in which much of the triglycerides that accumulate in avian adipose tissue are synthesized. In order to better understand the gene expression and its regulation in chicken liver, the gene expression profiles of liver at developmental stages of chicken (1 week, 4 weeks and 7 weeks of age) were investigated and differentially expressed genes between lean and fat chicken lines divergently selected for abdominal fat content for eight generations were screened. Our data indicated that 4 weeks of age was a very important stage on chicken liver lipogenesis compared to 1 week and 7 weeks of age, and the glycometabolism in chicken liver could be related to lipid metabolism and the difference of glycometabolism could be another potential reason for the fat and lean phenotype occurrence besides the difference of lipogenesis in chicken liver. Our result have established groundwork for further study of the basic genetic control of chicken obesity and will benefit chicken research communities as well as researches that use chicken as a model organism for developmental biology and human therapeutics.