Effect of different bedding depths of rice hulls on growth performance and carcass traits of White Pekin ducks.

Duck meat is recognized as a healthier poultry product that contains higher amounts of unsaturated and essential fatty acids, iron, and excellent amounts of protein. It has been found to possess the ability to reduce low-density lipoprotein cholesterol and subsequently, blood pressure in the human body; and improve the immunity system. The current study investigated the appropriate bedding depths of rice hulls as a preferred bedding material by evaluating the growth performance and carcass traits of White Pekin ducks raised for 42 days. A total of 288 one-day-old White Pekin ducklings were randomly allotted to floor cages with one of four bedding depths at 4 cm, 8 cm, 12 cm, and 16 cm. Ducklings were fed standard duck starter (days 1-21) and finisher (days 22-42) diets. The birds were stocked at a rate of 6 birds/m2 with 6 replicates per treatment. Growth performance evaluation for the body weight, average daily gain, and average daily feed intake were measured to calculate the weekly feed conversion ratio. Breast, leg, and carcass yield were assessed as carcass traits. The muscle color and proximate composition were also analyzed for meat quality. Footpad dermatitis was also evaluated on day 42. Ducks reared on 16 cm bedding depth over the 42 days recorded higher (p < 0.05) body weight, average daily, average daily feed intake, and improved feed conversion ratios compared to other groups. The crude fat in breast meat also lowered (p < 0.05) in ducks reared at 16 cm (1.02%) when compared to ducks raised at 4 cm bedding depth (2.11%). Our results showed improved redness (p < 0.05) when the depth of bedding materials was elevated. Except for the breast meat fat, the dissimilar bedding depths did not affect (p < 0.05) the breast and leg meat composition, footpad dermatitis, and mortality for the current study. In conclusion, this study indicated that the bedding depths would directly or indirectly affect the growth performance and meat color of White Pekin ducks; and the bedding depth of rice hulls at 16 cm improved the growth performance of White Pekin ducks for 42 days.

Runs of homozygosity analysis for selection signatures in the Yellow Korean native chicken.

Objective: Yellow Korean native chicken (KNC-Y) is one of the five pure Korean indigenous chicken breeds that were restored through a government project in 1992. KNC-Y is recognized for its superior egg production performance compared to other KNC lines. In this study, we performed runs of homozygosity (ROH) analysis to discover selection signatures associated with egg production traits in the KNC-Y population. Methods: A total of 675 DNA samples from KNC-Y were genotyped to generate single nucleotide polymorphism (SNP) data using custom 60K Affymetrix SNP chips. ROH analysis was performed using PLINK software, with predefined parameters set for the analysis. The threshold of ROH island was defined as the top 1% frequency of SNPs withing the ROH among the population. Results: In the KNC-Y population, a total of 29,958 runs of homozygosity (ROH) fragments were identified. The average total length of ROH was 120.84 Mb, with each ROH fragment having an average length of 2.71 Mb. The calculated ROH-based inbreeding coefficient (FROH) was 0.13. Furthermore, we revealed the presence of ROH islands on chromosomes 1, 2, 4, 5, 7, 8, and 11. Within the identified regions, a total of 113 genes were annotated, and among them were genes related to economic traits, including PRMT3, ANO5, HDAC4, LSS, PLA2G4A, and PTGS2. Most of the overlapping quantitative trait locus (QTL) regions with ROH islands were found to be associated with production traits. Conclusion: This study conducted a comprehensive analysis of ROH in the KNC-Y population. Notably, among the findings, the PTGS2 gene is believed to play a crucial role in influencing the laying performance of KNC-Y.

Laying hen responses to multi-strain Bacillus-based probiotic supplementation from 25 to 37 weeks of age.

OBJECTIVE: This study aimed to investigate the efficacy of Bacillus-based probiotics supplemented at two different levels to modulate the productive performance, egg quality, tibia traits, and specific cecal bacteria counts of Hy-Line Brown layers from 25 to 37 weeks of age. METHODS: A total of 216 twenty-five-week-old hens were randomly distributed into 3 experimental diets with 12 replicates of 6 birds per cage. Diets included basal diet supplemented with 0 (CON), 3×108 (PRO1), or 3×109 (PRO2) colony-forming unit (CFU) of the test probiotic containing Bacillus subtilis PB6, Bacillus subtilis FXA, and Bacillus licheniformis G3 per kilogram of feed. RESULTS: Improved egg weights and mass at 29 weeks; and feed intake at 31 weeks (p<0.10) were noticed with the probiotic-supplemented PRO1 and PRO2 diets. Considering egg quality, the shell thickness, Haugh units, and yolk color were improved; but yolk cholesterol was lowered (p<0.05) with PRO1 and PRO2 diets at 29 weeks. At both 33 and 37 weeks, the egg-breaking strength, shell color and thickness, albumen height, Haugh units, and yolk color were improved; but yolk cholesterol was similarly lowered (p<0.05) with the PRO1 and PRO2 diets. Improved tibia Ca, ash, weights, and density; and raised cecal counts of Bifidobacteria and Lactobacilli (p<0.05) were noticed with PRO1 and PRO2 diets. Improved tibia P but reduced Clostridia counts (p<0.10) were also observed with the PRO1 and PRO2 diets. CONCLUSION: Probiotic supplementation of Bacillus subtilis PB6, Bacillus subtilis FXA, and Bacillus licheniformis G3 at 3×108 CFU/kg of feed is adequate to significantly improve egg quality, lower yolk cholesterol, enhance several tibia traits, and raise the populations of beneficial cecal bacteria. Modest improvements in several productive parameters and tibia P but reduced Clostridia were also observed; and could warrant further investigation of probiotic effects beyond the current test period.

Xylanase supplementation in energy-deficient corn-based diets: impact on broiler growth, nutrient digestibility, chyme viscosity and carcass proximates.

OBJECTIVE: The goal of the current study was to investigate the impact of various concentrations of xylanase in energy-deficient corn-based diets on the growth performance, carcass characteristics, nutrient digestibility, and digesta viscosity in broilers from 7 to 35 days of age. METHODS: A total of 280 seven-day-old Ross 308 broilers were randomly allocated to one of the five dietary treatments following a completely randomized design with 8 replicates and 7 birds per cage. The treatments were: i) positive control (PC, without xylanase); ii) NC-1 (80 kcal/kg ME reduced from PC); iii) NC-2 (100 kcal/kg ME reduced from PC); iv) NCX-1 (NC-1 + 2,000 U/kg xylanase); and v) NCX-2 (NC-2 + 3,000 U/kg xylanase). Body weight, weight gain, feed intake, and feed conversion ratio were determined weekly to evaluate growth performance. One bird per pen was sacrificed for ileal digesta collection to determine the viscosity and digestibility of energy, dry matter, crude protein on days 24 and 35, however breast and leg meat samples were obtained for proximate analysis (moisture, crude protein, fat, and ash) on day 35. RESULTS: Birds fed diets supplemented with xylanase regardless of the amount had higher (p<0.05) body weights, daily gains, and improved feed efficiency compared to NC diets all throughout the experimental period. Feed intake was not affected (p>0.05) by the addition of xylanase. Moreover, lowered (p<0.05) viscosity of the ileal digesta were observed upon xylanase inclusion in the diets compared to the birds fed NC diets on day 24. Ileal nutrient digestibility and meat proximate composition were not affected (p>0.05) by xylanase. CONCLUSION: The present study indicated that the xylanase at 2,000 U/kg and 3,000 U/kg levels compensates for the 80 kcal/kg and 100 kcal/kg dietary energy levels, respectively, without having adverse effects on the growth performance, carcass characteristics, nutrient digestibility, and digesta viscosity of broilers.

Major histocompatibility complex genes exhibit a potential immunological role in mixed Eimeria-infected broiler cecum analyzed using RNA sequencing.

OBJECTIVE: This study was conducted to investigate the differential expression of the major histocompatibility complex (MHC) gene region in Eimeria-infected broiler. METHODS: We profiled gene expression of Eimeria-infected and uninfected ceca of broilers sampled at 4, 7, and 21 days post-infection (dpi) using RNA sequencing. Differentially expressed genes (DEGs) between two sample groups were identified at each time point. DEGs located on chicken chromosome 16 were used for further analysis. Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis was conducted for the functional annotation of DEGs. RESULTS: Fourteen significant (false discovery rate <0.1) DEGs were identified at 4 and 7 dpi and categorized into three groups: MHC-Y class I genes, MHC-B region genes, and non-MHC genes. In Eimeria-infected broilers, MHC-Y class I genes were upregulated at 4 dpi but downregulated at 7 dpi. This result implies that MHC-Y class I genes initially activated an immune response, which was then suppressed by Eimeria. Of the MHC-B region genes, the DMB1 gene was upregulated, and TAP-related genes significantly implemented antigen processing for MHC class I at 4 dpi, which was supported by KEGG pathway analysis. CONCLUSION: This study is the first to investigate MHC gene responses to coccidia infection in chickens using RNA sequencing. MHC-B and MHC-Y genes showed their immune responses in reaction to Eimeria infection. These findings are valuable for understanding chicken MHC gene function.

Research Note: Evaluation of standardized ileal amino acid digestibility in feed ingredients for Pekin ducks.

The digestibility of crude protein (CP) and amino acids (AA) in feedstuffs including corn, soybean meal (SBM), and corn distillers dried grains with solubles (DDGS) was investigated in White Pekin ducks. The test ingredients were the sole source of AA and CP. A nitrogen-free diet was also formulated for determining endogenous losses of AA and nitrogen. Birds were fed a standard starter diet for the first 15 d posthatch. On d 16, 96 ducklings (860 ± 50 g BW) were selected and allocated into 1 of 4 dietary treatments containing the test ingredients with 6 replicates per treatment in a randomized complete block design. All the crumbled assay diets were offered ad-libitum for 5 d and contained chromic oxide as an indigestible marker at 0.05%. On d 21, ducks were euthanized to collect the ileal digesta for digestibility analysis. Basal endogenous losses were abundant in glutamine, aspartic acid, leucine, proline, and serine, consecutively. For apparent ileal digestibility (AID), lysine and methionine were the highest (P < 0.05) in SBM, followed by corn and DDGS. For threonine, the highest values (P < 0.05) were similarly noted for SBM, followed by DDGS and corn; the values were 80.44, 69.88, and 64.89%, consecutively. Considering standardized ileal digestibility (SID), higher values (P < 0.05) for SBM were similarly noted for all the amino acids including lysine, methionine, and threonine; the values were 89.40, 93.58, and 86.50%, respectively. Conclusively, improved AA and CP digestibility was noted with SBM. Dietary protein source affected the extent of digestibility at the distal ileum; and the utilization of digestible amino acid coefficients during ducks' feed formulation is emphasized.

Differences in bedding material could alter the growth performance of White Pekin ducks raised for 42 days.

The effect of different commercially available bedding materials on the growth performance and carcass characteristics of ducks for 42 days was investigated. 336 one-day-old White-Pekin ducklings (60.48 ± 0.16 g) were randomly allocated into 24-floor pens with one of the three beddings namely i) coco peat, ii) rice husks, or iii) sawdust. 14 ducklings per pen and 8 replicate pens per bedding material were used. Birds were fed a starter diet from days 1-21 and a grower diet from days 22-42. Weekly growth performance evaluation was conducted for the average body weight, weight gains, daily feed intake, and feed conversion efficiency. One bird per pen was sacrificed on day 42 for the evaluation of carcass characteristics including the carcass, breast, and leg muscle percentages. Breast and leg muscle samples were then collected and analyzed for their proximate and pH values. Higher body weights (p < 0.05) were noticed with rice husks on day 42 only. Improved daily gains (p < 0.05) were also noticed for birds raised with rice husks over the entire period (days 1-42). Concerning feed intake, higher values (p < 0.05) were similarly noted with rice husks for the grower phase (days 22-42), and the entire experimental period (days 1-42). Marginally improved feed intake values were also noted with the use of rice husks as the bedding materials on day 42 (p = 0.092). Improved feed efficiency (p < 0.05) was noticed with rice husks on day 35, the grower period, and the entire 42-day period. However, no significant differences were noticed for most of the carcass characteristics that were evaluated. Nevertheless, higher (p < 0.05) pH values for the breast muscle were noticed with the use of coco peat and sawdust as the bedding. Conclusively, the bedding type could have a significant impact on the growth performance of ducks without adverse effects on carcass characteristics. The use of rice husks as bedding might be advantageous and is therefore recommended.

Efficacy and Equivalency of Phytase for Available Phosphorus in Broilers Fed an Available Phosphorus-Deficient Diet.

This study was conducted to assess the effectiveness of phytase on the performance, carcass traits, nutrient digestibility, tibia characteristics, and inositol phosphorus (IP) degradation in broiler chickens. Additionally, the available phosphorus (AP) equivalency of phytase in AP-deficient diets was estimated for 35 days after hatching. A total of 336 one-day-old Ross 308 broiler chicks were allocated to one of seven dietary treatments with six replications with eight birds per cage. The dietary treatments were as follows: (1) positive control containing 0.45% AP of the starter and 0.42% AP of the grower diet (PC), (2) 0.10% AP deficiency from the PC (NC-1), (3) 0.15% AP deficiency from the PC (NC-2), (4) 0.20% AP deficiency from the PC (NC-3), (5) NC-3 +phytase (500 FTU/kg; NC-3-500), (6) NC-3 + phytase (1000 FTU/kg; NC-3-1000), and (7) NC-3 + phytase (1500 FTU/kg; NC-3-1500). On d 35, the NC-3 diet exhibited lower tibia weight compared to the other treatments (p < 0.001). The NC-3-1500 group had higher calcium and phosphorus contents in the tibia than the other treatments on d 35 (p < 0.01). Phytase supplementation led to a reduced IP6 concentration and increased IP3 concentrations in different sections of the gastrointestinal tract on d 21 and 35 compared to the control diet (p < 0.05). In conclusion, based on the tibia phosphorus content, this study determined that 500 FTU/kg phytase was equivalent to 0.377% and 0.383% AP in the diet on d 21, and 0.317% and 0.307% AP in the diet on d 35, respectively. Likewise, 1000 FTU/kg was determined to be equivalent to 0.476% and 0.448% AP on d 21, and 0.437% and 0.403% AP on d 35, respectively. Furthermore, 1500 FTU/kg was determined to be equivalent to 0.574% and 0.504% AP on d 21, and 0.557% and 0.500 AP on d 35, respectively.

Combinatorial Effect of Dietary Oregano Extracts and 3,4,5-Trihydroxy Benzoic Acid on Growth Performance and Elimination of Coccidiosis in Broiler Chickens.

We aimed to compare the combinatorial effect of 3,4,5-trihydroxybenzoic acid (THB) and oregano extracts (OE) with THB alone on the growth performance and elimination of deleterious effects in coccidiosis-infected broilers. A total of 210 one-day-old broilers were randomly assigned to one of five dietary treatments, with six replicates each, for 35 days. Dietary treatments were: 1) non-challenged, non-treated (NC); 2) challenged, non-treated (PC); 3) PC+ Salinomycin (0.05 g/kg; AB); 4) PC+THB (0.1 g/kg; THB); and 5) PC+THB+OE (0.1 g/kg; COM). On day 14, all groups except for NC were challenged with a 10-fold dose of Livacox® T anticoccidial vaccine to induce mild coccidiosis. All treatments significantly improved (P<0.05) body weight, average daily gain, and average daily feed intake, compared to PC, on days 21, 28, and 35. However, all treatments significantly reduced (P<0.05) the feed conversion ratio of PC by more than 14.60% on day 35, 11.76% during growing period, and 10.36% through the entire period. Broilers receiving anticoccidial treatments had 54.23% and 51.86% lower lesion scores (P<0.05) at 4 and 7 days post-infection, respectively, compared to PC. Additionally, the villus height of COM was significantly longer (P < 0.05) than that of THB. Although the molecular action of COM remains unclear, OE addition to THB reduced the shedding of oocysts better than THB alone (P<0.05, 9-11 days post-infection). Most importantly, COM effectively minimized the mortality of challenged birds from as high as 11.90% (PC) to 0%, a level similar to NC and AB, while THB maintained a mortality of 2.38%. In conclusion, the anticoccidial effect of THB can be enhanced by the addition of OE for better animal performance and the elimination of deleterious effects from coccidiosis-infected broilers for 35 days.

Time-series transcriptome analysis identified differentially expressed genes in broiler chicken infected with mixed Eimeria species.

Coccidiosis caused by the Eimeria species is a highly problematic disease in the chicken industry. Here, we used RNA sequencing to observe the time-dependent host responses of Eimeria-infected chickens to examine the genes and biological functions associated with immunity to the parasite. Transcriptome analysis was performed at three time points: 4, 7, and 21 days post-infection (dpi). Based on the changes in gene expression patterns, we defined three groups of genes that showed differential expression. This enabled us to capture evidence of endoplasmic reticulum stress at the initial stage of Eimeria infection. Furthermore, we found that innate immune responses against the parasite were activated at the first exposure; they then showed gradual normalization. Although the cytokine-cytokine receptor interaction pathway was significantly operative at 4 dpi, its downregulation led to an anti-inflammatory effect. Additionally, the construction of gene co-expression networks enabled identification of immunoregulation hub genes and critical pattern recognition receptors after Eimeria infection. Our results provide a detailed understanding of the host-pathogen interaction between chicken and Eimeria. The clusters of genes defined in this study can be utilized to improve chickens for coccidiosis control.

Physiological responses of broiler chickens fed reduced-energy diets supplemented with emulsifiers.

OBJECTIVE: To investigate the physiological effects of exogenous emulsifiers in broiler chickens that were fed tallow-incorporated reduced-energy diets over 35 days. METHODS: A total of 256 Ross 308 one-day-old broilers (42.28±0.16 g) were randomly allocated in a 2×2 factorial arrangement to 32 pens with eight chicks per cage. Birds were fed one of four dietary treatments as follows: i) positive control (PCN; energy sufficient diet); ii) negative control (NCN; energy-deficient diet, -100 ME kcal/kg); iii) PCL (PCN plus 0.05% emulsifier); and iv) NCL (NCN plus 0.05% emulsifier). Growth performance was evaluated weekly whereas assessments for the carcass traits, digestibility, some blood metabolites, ileal morphology, and meat quality were measured on d 21 and d 35. RESULTS: Birds fed the NCL diet had higher (p<0.05) body weights, daily gains, daily feed intake, and improved feed efficiency over the entire 35-day period. Improvements (p<0.05) for the ileal digestibility of crude fat, energy, and dry matter commensurate with longer (p<0.05) villus heights were also observed with emulsifiers in the NCL and PCL diets. For the carcass measurements, only the liver weights were increased (p<0.05) with emulsifiers in the supplemented groups. For blood metabolites, higher (p<0.05) lipase levels were noticed with emulsifiers in the NCL and PCL diets. In addition, marginal reductions (p = 0.076; p = 0.095, respectively) were also noted with emulsifiers for the total cholesterol and triglyceride contents on d 35. Regarding meat quality, breast muscle yellowness was increased (p<0.05) with emulsifier use in supplemented groups. CONCLUSION: Our results suggest that emulsifier supplementation at 0.05% in diets could potentially improve the growth performance and nutrient digestibility of broilers over 35 days. This could compensate for the lower growth performance that could be recorded with fat-incorporated lower-energy diets.

Broiler responses to dietary 3,4,5-trihydroxybenzoic acid and oregano extracts under Eimeria challenge conditions.

This study was conducted to evaluate the efficacy of a combination 3,4,5-trihydroxybenzoic acid (THB) and oregano extracts (i.e., Carvacrol and Thymol) at intake/dietary different levels on growth performance, intestinal health indicators, immune responses and fecal oocyst shedding in broiler chickens under Eimeria challenged condition. A total of 336 one-day-old broilers were randomly assigned to one of six dietary treatments with seven replications per treatment. Dietary treatments were: i) Non-challenged bird without any dietary treatment (NCNT), ii) Challenged bird without any dietary treatment (CNT), iii) Challenged birds fed a THB diet (0.1 g/kg, THB), iv) Challenged birds fed a combination of THB and oregano extracts diet (0.1 g/kg, COM 100), and a gradual increase of combination of THB and oregano extracts likely v) 0.15 g/kg (COM 150), and 0.2 g/kg (COM 200). On day 14, all groups except for NCNT have orally challenged with a 10-fold dose of Livacox® T anticoccidial vaccine to trigger coccidiosis. The results indicated that Eimeria-challenged broilers fed COM 100 and COM 200 diets increased (p < 0.05) body weight than CNT diet on day 35. Furthermore, birds fed COM 100 and COM 200 diets increased (p < 0.05) average daily gain compared to those fed CNT diets for the entire experimental period. There is no significant (p > 0.05) in average daily feed intake, feed efficiency between NCNT and birds fed with combined THB and oregano extracts for the entire experimental period. A combination of THB and oregano extract regardless of concentration levels or THB alone reduced (p < 0.05) lesion score in ileum compared to the CNT diet for 7 days post-infection (dpi). Birds fed COM 100 diet had lower (p < 0.05) intestinal lesion scores in jejunum and caeca on 7 dpi compared to those were in the CNT diet. No (p > 0.05) difference was observed in the oocysts per gram of feces count, intestinal morphology, carcass traits and blood cytokine concentration among the infected treatments. Collectively, we conclude that birds fed with a combination of THB and oregano extracts regardless of the ratios that were used demonstrated better recovery of health after the coccidial challenge than using only THB alone.