Evaluation of dietary metabolizable energy concentrations on meat quality and lipid metabolism-related gene expression in yellow-feathered chickens.

This study evaluated the effects of different dietary metabolizable energy (ME) concentrations on the meat quality, carcass traits, volatile flavour and lipid metabolism-related gene expression levels in yellow-feathered chickens. In total, 600 Huxu female chickens aged 90 days were randomly assigned to six dietary treatments, each with 10 replicates of 10 birds. During the finisher phase, the birds were fed diets containing 2880 (low), 2940, 3000, 3060, 3120 and 3180 (high) kcal ME/kg. The results showed that the average daily gain of chickens increased as the dietary ME concentration increased, while the feed to gain improved (p < 0.05), and the intramuscular fat content of breast muscle increased (p < 0.05). The energy concentration had no effect on the breast muscle pH (45 min and 24 h), colour parameter (L*) or percentage of drip loss (p > 0.05), but the shear force values decreased significantly (p < 0.05). The diameter and area of the breast muscle fiber decreased and the muscle fibre density increased as the dietary ME concentration increased (p < 0.05). The highest ME concentration (3180 kcal) increased the percentages of aldehydes (hexanal, heptanal, 2,4-nonadienal, octanal, nonanal and 2-decenal), alcohols (2-nonen-1-ol, trans-2-undecen-1-ol, 7-hexadecenal, 2-hexyl-1-decanoal and n-nonadecanol-1,3,7,11-trimethyl-1-dodecanol), alkanes (2,6-dimethyl-heptadecane) and carboxylic acids (9-hexadecenoic acid), but reduced the percentages of octadecanal, octadecane, heneicosane and tetradecanal (p < 0.05). In addition, the mRNA gene expression levels of fatty acid-binding protein 3 and apolipoprotein B were significantly upregulated in the liver, whereas that of cholesteryl ester transfer protein was significantly downregulated. In conclusion, increasing the ME diet to 3180 kcal/kg significantly improved the quality and flavour of the meat from yellow-feathered broilers. our finding may help poultry producers to improve the taste of meat by regulating genes related to lipid metabolism, thereby achieving the flavour and taste characteristics preferred by consumers.

Effects of dietary methionine on productivity, reproductive performance, antioxidant capacity, ovalbumin and antioxidant-related gene expression in laying duck breeders.

The study investigated whether dietary methionine (Met) affects egg weight and antioxidant status through regulating gene expression of ovalbumin (OVAL), nuclear factor erythroid 2 like 2 (Nrf2) and haem oxygenase 1 (HO-1) in laying duck breeders. Longyan duck breeders (n 540, 19 weeks) were randomly assigned to six treatments with six replicates of fifteen birds each. Breeders were fed diets with six Met levels (2·00, 2·75, 3·50, 4·25, 5·00 and 5·75 g/kg) for 24 weeks. The egg weight (g), egg mass (g/d), feed conversion ratio, hatchability, 1-d duckling weight, albumen weight, albumen proportion and OVAL mRNA level improved with dietary Met levels, whereas yolk proportion decreased (P<0·05). The weight of total large yellow follicles increased linearly (P<0·001) and quadratically (P<0·05) with dietary Met concentration, and their weight relative to ovarian weight showed a linear (P<0·05) effect. Dietary Met level had a linear (P<0·05) and quadratic (P<0·001) effect on the gene expression of glutathione peroxidase (GPX1), HO-1 and Nrf2, and quadratically (P<0·05) increased contents of GPX and total antioxidant capacity (T-AOC) in liver of duck breeders. In addition, maternal dietary Met enhanced gene expression of GPX1, HO-1 and Nrf2, increased contents of GPX and T-AOC and reduced carbonylated protein in the brains of hatchlings. Overall, dietary Met concentration affected egg weight and albumen weight in laying duck breeders, which was partly due to gene expression of OVAL in oviduct magnum. A diet containing 4·0 g Met/kg would achieve optimal hepatic GPX1 and Nrf2 expression, maximise the activity of GPX and minimise lipid peroxidation.

Dietary vitamin A supplementation improved reproductive performance by regulating ovarian expression of hormone receptors, caspase-3 and Fas in broiler breeders.

The effects of dietary vitamin A (VA) supplementation on reproductive performance, VA deposition, and potential mechanisms of action were studied in Chinese yellow-feathered broiler breeders. A total of 528 yellow-feathered broiler breeders that were 46 wk old were fed a corn-soybean meal basal diet supplemented with 0; 5,400; 10,800; or 21,600 IU/kg VA for 9 wk. Each dietary treatment had 6 replicates with 22 birds per replicate. After 7 wk of treatment, 60 settable eggs per replicate were collected for hatching. The results showed that dietary VA improved the laying rate, egg-to-feed ratio, and hatch weight of offspring (P < 0.05). Hepatic retinyl palmitate in broiler breeders and hatchlings (within 12 h) increased with increasing VA (P < 0.05). VA supplementation increased insulin-like growth factor 1 (IGF-I) receptor transcripts in the ovarian stroma and the walls of yellow follicles, follicle stimulating hormone (FSH) receptor expression in the walls of white and yellow follicles, and luteinizing hormone (LH) receptor and growth hormone (GH) receptor transcripts in the walls of yellow follicles (P < 0.05). Caspase-3 and Fas mRNA levels in the ovarian stroma and the walls of white and yellow follicles decreased with VA supplementation (P < 0.05). The relative expression of retinol dehydrogenase 10 (RDH10) transcripts in the walls of white follicles increased with 5,400 IU/kg VA supplementation (P < 0.05). Supplemental 21,600 IU/kg VA increased cytochrome P450 26A1 (CYP26A1) transcripts in the ovarian stroma and the walls of white follicles (P < 0.05). Dietary VA elevated retinoic acid receptor α (RARα) expression in the ovarian stroma and the walls of yellow follicles and retinoid X receptor α (RXRα) expression in the walls of yellow follicles. It was concluded that VA supplementation improved reproductive performance and hepatic storage of VA, and this was associated with the regulation of ovarian hormone receptor expression and suppression of apoptosis gene transcripts through its active metabolite retinoic acid (RA). The optimal dietary VA level for Chinese yellow-feathered broiler breeders at 46 to 54 wk of age was found to be 10,800 IU/kg.

Effects of L-Methionine and DL-Methionine on Growth Performance, Methionine-Metabolizing Enzyme Activities, Feather Traits, and Intestinal Morphology of Medium-Growing, Yellow-Feathered Chickens between 1 and 30 Days of Age.

This experiment investigated the effects of L-Methionine (L-Met) on growth performance, Met-metabolizing enzyme activity, feather traits, and small intestinal morphological characteristics, and compared these with DL-Methionine (DL-Met) for medium-growing, yellow-feathered broilers during the starter phase. Furthermore, the aim was to provide recommendations for the appropriate dietary Met levels in feed. A total of 1584 1-d broilers were randomly divided into 11 treatment groups with six replicates of 24 birds each: basal diet (CON, Met 0.28%), basal diet + L-Met (0.04%, 0.08%, 0.12%, 0.16%, 0.20%), and basal diet + DL-Met (0.04%, 0.08%, 0.12%, 0.16%, 0.20%). The total trial period was 30 days. Compared with broilers fed the basal diet, those fed 0.04 to 0.20% supplemental Met had higher final body weight (FBW), average daily feed intake (ADFI), average daily gain (ADG), and lower feed-to-gain ratio (F: G) (p < 0.05). Compared with DL-Met groups, the L-Met group had higher FBW and ADG (p < 0.05). The relative bioavailability (RBV) of L-Met in ADG of 1-30 d was 142.5%. Chicks fed diets supplemented with L-Met had longer fourth primary feather lengths compared to birds fed the control and diets supplemented with DL-Met (p < 0.05). Compared to the control, birds supplemented with DL-Met or L-Met had an increased moulting score (p ≤ 0.05). Chicks fed diets supplemented with L-Met had lower activities of methionine adenosyl transferase (MAT) compared to those fed the basal diet or supplemented with DL-Met (p < 0.05). Chicks supplemented with either DL-Met or L-Met had higher activities of cystathionine ß-synthase (CBS) than those fed the basal diet (p < 0.05). Compared with the control, chicks fed diets supplemented with either DL-Met or L-Met had an enhanced level of albumin in plasma (p < 0.05). There were no obvious differences in the plasma content of uric acid and total protein among the treatments (p > 0.05). Chicks fed diets supplemented with either DL-Met or L-Met had higher villus height and V/C in the duodenal than chicks fed the basal diet (p < 0.05). The jejunum morphology was not affected by either L-Met or DL-Met supplementation (p > 0.05). Therefore, dietary supplementation with DL-Met or L-Met improved the growth performance, feather traits, and intestinal morphological characteristics of medium-growing, yellow-feathered broiler chickens aged 1 to 30 d by decreasing the enzyme activities of Met methylation (MAT) and increasing the enzyme activities of the sulfur transfer pathway (CBS), and supplementation with L-Met showed a better improvement compared with DL-Met. The relative efficacy of L-Met to DL-Met was 142.5% for ADG of yellow-feathered broilers. The appropriate Met levels for medium-growing, yellow-feathered broilers are between 0.36~0.38% (supplementation with DL-Met) or 0.32~0.33% (supplementation with L-Met) when based on ADG and feed-to-gain ratio.

Dietary supplementation with anthocyanin attenuates lipopolysaccharide-induced intestinal damage through antioxidant effects in yellow-feathered broiler chicks.

This study investigated the protective effects of anthocyanin (AC) supplementation on lipopolysaccharide (LPS)-challenged yellow-feathered broiler chicks. A total of 480 1-d female broiler chicks were randomly assigned to 4 treatment groups: basal diet (CON), basal diet + LPS-challenge (LPS), supplementation with 100 or 400 mg/kg AC + LPS-challenge (AC100, AC400). On d 17 and d 19, birds in LPS, AC100 and AC400 received an intramuscular dose of LPS, while birds in CON received saline. The result showed that (1) LPS injection significantly decreased (P < 0.05) body weight on d 21 and average daily gain of broiler chicks from 1 to 21 days of age, and supplementation with 100 mg/kg AC increased (P < 0.05) those of LPS-challenged broilers. (2) There were no differences among the treatments (P > 0.05) in relative weights of immune organs. (3) Supplementation with AC (AC100 and AC400) increased (P < 0.05) the jejunal villus height and villus height/crypt depth ratio (AC100) of LPS-challenged birds. Challenge with LPS decreased the relative expression of OCLN (Occludin), ZO-1, JAM2, and MUC2 in jejunal mucosa of broilers, and supplementation with AC offset the relative expression of ZO-1, JAM2 (AC100 and AC400), and OCLN (AC400) in LPS-injected broilers. (4) LPS-induced increase in the malondialdehyde (MDA) concentration and decreases in activity of total superoxide dismutase (T-SOD), and expression of SOD1, CAT and GPX in jejunal mucosa, were attenuated by dietary AC supplementation. In conclusion, in yellow-feathered broiler chicks, dietary supplementation with AC alleviated LPS-induced declined growth performance and mucosal damage of the intestine through antioxidant effects.

Dietary supplementation of bilberry anthocyanin on growth performance, intestinal mucosal barrier and cecal microbes of chickens challenged with Salmonella Typhimurium.

BACKGROUND: Anthocyanins (AC) showed positive effects on improving the intestinal health and alleviating intestinal pathogen infections, therefore, an experiment was conducted to explore the protective effects of supplemented AC on Salmonella-infected chickens. METHODS: A total of 240 hatchling chickens were randomly allocated to 4 treatments, each with 6 replicates. Birds were fed a basal diet supplemented with 0 (CON, and ST), 100 (ACL) and 400 (ACH) mg/kg of AC for d 60, and orally challenged with PBS (CON) or 109 CFU/bird (ST, ACL, ACH) Salmonella Typhimurium at d 14 and 16. RESULTS: (1) Compared with birds in ST, AC supplementation increased the body weight (BW) at d 18 and the average daily gain (ADG) from d 1 to 18 of the Salmonella-infected chickens (P < 0.05); (2) AC decreased the number of Salmonella cells in the liver and spleen, the contents of NO in plasma and inflammatory cytokines in ileal mucosa of Salmonella-infected chickens (P < 0.05); (3) Salmonella infection decreased the ileal villi height, villi height to crypt depth (V/C), and the expression of zonulaoccludins-1 (ZO-1), claudin-1, occludin, and mucin 2 (MUC2) in ileal mucosa. AC supplementation relieved these adverse effects, and decreased ileal crypt depth (P < 0.05); (4) In cecal microbiota of Salmonella-infected chickens, AC increased (P < 0.05) the alpha-diversity (Chao1, Pd, Shannon and Sobs indexes) and the relative abundance of Firmicutes, and decreased (P < 0.05) the relative abundance of Proteobacteria and Bacteroidota and the enrichment of drug antimicrobial resistance, infectious bacterial disease, and immune disease pathways. CONCLUSIONS: Dietary AC protected chicken against Salmonella infection via inhibiting the Salmonella colonization in liver and spleen, suppressing secretion of inflammatory cytokines, up-regulating the expression of ileal barrier-related genes, and ameliorating the composition and function of cecal microbes. Under conditions here used, 100 mg/kg bilberry anthocyanin was recommended.

Transcriptome and proteome profile of jejunum in chickens challenged with Salmonella Typhimurium revealed the effects of dietary bilberry anthocyanin on immune function.

Introduction: The present study investigated the effects of bilberry anthocyanin (BA) on immune function when alleviating Salmonella Typhimurium (S. Typhimurium) infection in chickens. Methods: A total of 180 newly hatched yellow-feathered male chicks were assigned to three groups (CON, SI, and SI + BA). Birds in CON and SI were fed a basal diet, and those in SI + BA were supplemented with 100 mg/kg BA for 18 days. Birds in SI and SI + BA received 0.5 ml suspension of S. Typhimurium (2 × 109 CFU/ml) by oral gavage at 14 and 16 days of age, and those in CON received equal volumes of sterile PBS. Results: At day 18, (1) dietary BA alleviated weight loss of chickens caused by S. Typhimurium infection (P < 0.01). (2) Supplementation with BA reduced the relative weight of the bursa of Fabricius (P < 0.01) and jejunal villus height (P < 0.05) and increased the number of goblet cells (P < 0.01) and the expression of MUC2 (P < 0.05) in jejunal mucosa, compared with birds in SI. (3) Supplementation with BA decreased (P < 0.05) the concentration of immunoglobulins and cytokines in plasma (IgA, IL-1ß, IL-8, and IFN-ß) and jejunal mucosa (IgG, IgM, sIgA, IL-1ß, IL-6, IL-8, TNF-α, IFN-ß, and IFN-γ) of S. Typhimurium-infected chickens. (4) BA regulated a variety of biological processes, especially the defense response to bacteria and humoral immune response, and suppressed cytokine-cytokine receptor interaction and intestinal immune network for IgA production pathways by downregulating 6 immune-related proteins. Conclusion: In summary, the impaired growth performance and disruption of jejunal morphology caused by S. Typhimurium were alleviated by dietary BA by affecting the expression of immune-related genes and proteins, and signaling pathways are related to immune response associated with immune cytokine receptors and production in jejunum.

Feed Restriction Improves Lipid Metabolism by Changing the Structure of the Cecal Microbial Community and Enhances the Meat Quality and Flavor of Bearded Chickens.

Excessive fat deposition in full-fed Bearded chickens does not only reduce carcass yield but also causes consumer rejection of meat. Feed restriction (FR) is an effective method to save on feed cost, reduce carcass fat deposition, and improve meat quality. A total of 560 150-d Bearded chickens were randomly divided into seven groups (each with eight replicates of ten birds) for 40 days. The control group was fed with the basal diet ad libitum (CON), and the other six groups were fed with 90% of the feed intake (90% FI), 80% FI, 70% FI, 90% metabolizable energy (90% ME), 80% ME, and 70% ME of the CON, respectively. Compared to the CON group, FR increased meat yield, but the total weight of the Bearded chickens was slighter; 80% FI and 70% ME improved the relative lipid metabolism indices of chickens, especially the levels of triglycerides and total cholesterol in the plasma and liver (p < 0.05), and decreased calpastatin activity in the breast muscle (p < 0.05). Additionally, 16S rRNA sequencing of cecal microbial community indicated that an increase in the abundance of Hydrogenoanaerobacterium and Bacteroides plebeius was observed in the 80% FI group (p < 0.05), and an enrichment in Olsenella, Catabacter, and Lachnospiraceae were observed in the 70% ME group (p < 0.05) compared to the CON group. Moreover, compared to the CON group, the L * value of the breast muscle significantly decreased, and a * value significantly increased in the 80% FI group (p < 0.05). Notably, the concentrations of threonine, lysine, aspartic acid, glutamic acid, proline, and arginine and the activity of calpain in breast muscle increased in the 80% FI group more than in the CON group (p < 0.05), while valine, isoleucine, leucine, phenylalanine, lysine, alanine, tyrosine and proline decreased in ME restriction groups (p < 0.05). Taken together, our results indicated that 80% FI could improve lipid metabolism by changing the structure of the cecal microbial community, and the meat quality and flavor of the Bearded chickens in 80% FI group was improved with a promoted meat color score, flavor substances, and the calproteinase system.

Dietary fiber modulates abdominal fat deposition associated with cecal microbiota and metabolites in yellow chickens.

Excessive deposition of abdominal fat is a public concern in the yellow chicken industry related to human nutrition. The common practice of nutritionists is to increase the fiber content in feed to control abdominal fat deposition of chickens. Corncob meal (CCM) is the cheapest ingredient widely used in animal diets. The possible effects of CCM on chicken abdominal fat deposition and the possible mechanism involving cecal microbiota remain unknown. The objectives of this study were to investigate the effects of CCM in modulating abdominal fat deposition and the role of the cecal microbiota and their metabolites. A total of 200 ninety-day-old Huxu female chickens were divided into 2 dietary treatments, each with 10 replicates of 10 birds, and were fed two finisher diets, from 90 to 135 d. The diets were a typical corn-soybean control diet (CON) and that diet with CCM partially replacing corn and corn gluten meal. Results showed that the CCM diet markedly decreased live weight and abdominal fat percentage (P < 0.05); chickens fed the CCM diet exhibited lower (P < 0.01) expression in abdominal fat of fatty acid binding protein 4 (FABP4), stearoyl-CoA desaturase (SCD), fatty acid synthase (FAS), and peroxisome proliferator-activated receptor γ (PPARγ) but higher (P < 0.05) expression of estrogen receptor alpha (ESR1). The CCM increased the abundance of Akkermansia (P < 0.05) and markedly reduced the relative cecal abundance of Phascolarctobacterium (P < 0.01), Rikenellaceae (P < 0.05), and Faecalibacterium (P < 0.01). The metabolomic and biochemical analyses demonstrated that the CCM diet increased (P < 0.05) the concentrations of butyrate in cecal contents. The majority of the metabolites in cecal digesta with differences in abundance were organic acids. The CCM diet increased (P < 0.05) contents of (R)-5-diphosphomevalote, pantothenic acid, 2-epi-5-epi-valiolone 7-phosphate, D-ribose 5-diphosphate, arbutin 6-phosphate, D-ribitol 5-phosphate, undecanoic acid, nicotinic acid, 4-methyl-2-oxovaleric acid, while decreasing (P < 0.05) those of oleic acid, glutaric acid, adipic acid, suberic acid, and L-fuculose 1-phosphate. In conclusion, these findings demonstrated that the dietary CCM treatment significantly decreased abdominal fat and altered the cecal microbiota and metabolite profiles of the yellow chickens.

Antrodia cinnamomea polysaccharide improves liver antioxidant, anti-inflammatory capacity, and cecal flora structure of slow-growing broiler breeds challenged with lipopolysaccharide.

Lipopolysaccharides (LPS) induces liver inflammatory response by activating the TLR4/NF-κB signaling pathway. Antrodia cinnamomea polysaccharide (ACP) is a medicinal mushroom that can protect from intoxication, liver injury, and inflammation. Nevertheless, the effect of ACP on the liver antioxidant, anti-inflammatory capacity and cecal flora structure of LPS-challenged broilers remains unclear. The aim of this experiment was to investigate the effects of ACP on the anti-oxidative and anti-inflammatory capacities of the liver, and cecal microbiota in slow-growing broilers stimulated by LPS. A total of 750 slow-growing broilers (9-day-old) were assigned to five treatments with 6 replicates of 25 chicks per replicate: a control diet, the chicks were fed a control diet and challenged with LPS. Dietary treatments 3 to 5 were the control diet supplemented with 100, 200, 400 mg/kg ACP challenged with LPS, respectively. The groups of 100 mg/kg ACP supplementation significantly increased liver index, pancreas index, and bursa of Fabricius index (P < 0.05). The GSH-Px content of LPS-challenged broilers was lower than that of the control group (P < 0.001), but the content of MDA increased (P < 0.001). Feeding with 100 mg/kg ACP resulted in increased the activity of T-AOC, GSH-Px, and T-SOD, and decreased MDA content (P < 0.05). The activity of TNF-α, IL-1ß, and IL-6 of the LPS group increased, but these indicators were decreased with supplemental 100 mg/kg ACP (P < 0.05). Dietary application of ACP up to 100 mg/kg down-regulated (P < 0.05) the expression of TLR4/NF-κB pathway in the liver induced by LPS. The results of 16S rRNA demonstrated that feeding with 100 mg/kg ACP can change the diversity and composition of the gut microbiota, and restrained the decline of beneficial cecal microbiota (typically Lactobacillus, Faecalibacterium, and Christensenellaceae R-7 group) in the challenged LPS group (P < 0.05). Conclusively, feeding a diet with 100 mg/kg ACP may have beneficial effects on liver damage and the bacterial microbiota diversity and composition in the ceca of LPS-stressed slow-growing broiler breeds, probably because of its combined favorable effects on antioxidants and cytokines contents, and restoration the decline of beneficial cecal microbiota.

Optimal Level of Supplemental Manganese for Yellow-Feathered Broilers during the Growth Phase.

This experiment investigated the effect of an optimized supplemental dietary manganese (Mn) on growth performance, tibial characteristics, immune function and meat quality, of yellow-feathered broilers. In three rearing periods, birds were fed for 21-d periods, from d 1 (starter), d 22 (grower) and d 43 (finisher), respectively, with basal diets (containing 16, 17, and 14 mg/kg analyzed Mn, respectively) supplemented with 0, 20, 40, 60, 80, 100, 120 and 140 mg/kg Mn. For starter phase broilers, supplemental manganese affected feed to gain ratio (F/G), and the minimum value was observed with 120 mg/kg manganese. During the grower phase, ADG increased quadratically (p < 0.05) with supplemental Mn and was maximal with 54 mg/kg additional manganese estimated using the regression equation. There was no influence of supplemental manganese on growth performance of broilers during the finisher phase (p > 0.05). The thymic relative weight of broilers were linearly (p < 0.05) and quadratically (p < 0.05) increased with supplemental Mn and maxima were obtained with 95 and 110 mg/kg additional Mn at 42 d and 63 d. The bone density of the tibia in broilers at d 21, 42 and 63 were increased quadratically (p < 0.05) by supplemental Mn, and optimal supplementation for the three phases was 52, 60 and 68 mg/kg, respectively. The weight, diameter, breaking strength and bone density of the tibia of 63-d broilers were influenced (p < 0.05) by supplemental manganese. The lightness (L*) value (linear, p < 0.05) and yellowness (b*) value (p < 0.05) of the breast muscle were decreased by dietary manganese supplementation, and the optimal supplementation, based on L*, was 86 mg/kg. In conclusion, supplemental Mn affected the growth performance, thymic relative weight, tibial characteristics, and the meat color of yellow-feathered broilers. From the quadratic regressions, the optimal supplementation of yellow-feathered broilers at the starter, grower and finisher phases to achieve the best performance was 52, 60, and 68 mg/kg, respectively.

Effects of Clostridium butyricum, Sodium Butyrate, and Butyric Acid Glycerides on the Reproductive Performance, Egg Quality, Intestinal Health, and Offspring Performance of Yellow-Feathered Breeder Hens.

Butyrate has been reported to promote the performance and growth of chickens. The specific roles and efficacy of different sources of butyrate remained unclear. Thus, the present study aimed to investigate and compare the effects of Clostridium butyricum (CB), sodium butyrate (SB), and butyric acid glycerides (tributyrin, BAG) on the reproductive performance, egg quality, intestinal health, and offspring performance of yellow-feathered breeder hens. A total of 300 Lingnan yellow-feathered breeder hens were assigned to five treatment groups: control (CL), 1×108CFU/kg CB (CBL), 1×109CFU/kg CB (CBH), 500mg/kg SB, and 300mg/kg BAG. Results showed that the laying performance and egg quality were increased by CBL, CBH, and BAG. Both CB treatments increased the hatchability of fertilized eggs. Maternal supplementation with both levels of CB significantly elevated the growth performance of offspring. Treatment with CBL, CBH, SB, and BAG all improved the oviduct-related variables and reduced the plasmal antioxidant variables. The CBH, CBL, and BAG treatments also improved the intestinal morphology to different degrees. Jejunal contents of IL-6 were decreased by CBH and BAG, while those of IL-4, IL-6, IL-1ß, and IgY were decreased by SB. Transcripts of nutrient transporters in jejunal mucosa were also upregulated by CBH, CBL, and SB treatments and expression of Bcl-2-associated X protein was decreased by CBL, CBH, and BAG. In cecal contents, CBL increased the abundance of Firmicutes and Bacillus, while CBH decreased the abundance of Proteobacteria. Also, the co-occurrence networks of intestinal microbes were regulated by CBH and BAG. In conclusion, dietary inclusion of CB and BAG improved the reproductive parameters, egg quality, and intestinal morphology of breeders. CB also influenced the hatching performance of breeders and growth performance of the offspring, while SB improved the oviduct-related variables. These beneficial effects may result from the regulation of cytokines, nutrient transporters, apoptosis, and gut microbiota; high-level CB had more obvious impact. Further study is needed to explore and understand the correlation between the altered gut microbiota induced by butyrate and the performance, egg quality, intestinal health, and also offspring performance.

Effects of dietary oregano essential oil supplementation on growth performance, intestinal antioxidative capacity, immunity, and intestinal microbiota in yellow-feathered chickens.

Essential oils are plant-derived aromatic volatile oils, and they contain bioactive compounds that have been shown to improve poultry nutrition. In this study, we investigated the effects of oregano essential oil (OEO) on intestinal antioxidative capacity, immunity, and gut microbiota of young yellow-feathered chickens. A total of nine hundred and sixty 1-d-old female Qingyuan partridge chickens were randomly allocated to four treatment groups with six replicates of 40 birds each, and the feeding trial was lasted for 30 d. The controls were fed on a basal diet without in-feed antibiotics; the birds in the antibiotic group were fed the basal diet supplemented with 20 mg/kg virginiamycin; the remaining birds were fed the basal diet containing 150 or 300 mg/kg OEO, respectively. Dietary supplementation with 150 or 300 mg/kg OEO increased average daily feed intake (P = 0.057) and average daily gain (P < 0.05). The activities of glutathione peroxidase and total antioxidative capacity in plasma, jejuna, and ileal mucosa were increased by OEO supplementation (P < 0.05), with a trend of lower jejunal content of malonaldehyde (P = 0.062). Moreover, dietary OEO increased the content of secretory immunoglobulin A (P = 0.078) and the relative expression of Claudin 1, Mucin 2, and Avain beta-defensin 1 in ileum (P < 0.05). Sequencing data of 16S rRNA indicated that dietary OEO increased the relative abundance of Firmicutes phylum, and Clostridium and Lactobacillus genera, and decreasing that of Romboutsia. Functional analyses indicated that microbial amino sugar and nucleotide sugar metabolism, replication, and repair systems were higher in OEO groups than those of controls and antibiotic treatment. In conclusion, dietary supplementation with OEO enhanced growth performance, alleviated local oxidative stress in intestine, improved production of natural antibodies, and favorably modulated intestinal microbiota composition.

High dietary copper induces oxidative stress and leads to decreased egg quality and reproductive performance of Chinese Yellow broiler breeder hens.

The objective of this study was to investigate the effects of dietary copper (Cu) on production, egg quality, and hatchability of Chinese Yellow broiler breeder hens and growth performance of their offspring. A total of 576 30-week-old hens were randomly allotted into 6 groups, each with 6 replicates (8 cages for each replicate with 2 birds per cage). The basal diet contained 3.50 mg/kg Cu, and the other 5 treatment diets contained 8.5, 13.5, 23.5 43.5, and 83.5 mg/kg Cu, respectively, additionally supplemented with Cu on the basal diet. The trial lasted for 15 wk. Qualified egg rate of birds fed 23.5 or 83.5 mg/kg Cu was significantly decreased (P < 0.05) compared with those given 3.5, 8.5, or 13.5 mg/kg Cu. Plasma malondialdehyde concentration showed quadratic effect (P = 0.002) which that decreased first then increased with dietary Cu increased. Highest values of Cu content and hepatic activity of Cu-ATPase occurred in hens fed 83.5 mg/kg dietary Cu with linear (P = 0.001) and quadratic (P = 0.001) effects. Shell strength and proportion on 18th day of live embryos of hens fed 13.5 mg/kg Cu were the greatest compared with other groups respectively (P < 0.05); rate of qualified eggs for hatch and hatchability of fertilized eggs of hens fed 83.5 mg/kg Cu were the least (P < 0.05). In conclusion, both inadequate (3.5 mg/kg diet) and excess (83.5 mg/kg) of dietary Cu can induce oxidative stress in hens and lead to decreased egg quality. Hatchability and growth performance of offspring were decreased when breeder hens were fed excess Cu in spite of greater hatching weight. The appropriate dietary Cu level for Chinese Yellow broiler breeder hens during the egg-laying period is 15.7 to 21.2 mg/kg (1.81-2.44 mg Cu fed per day) when based on Cu level and Cu-ATPase activity in the liver. This dietary Cu requirement is approximately doubled (∼40 mg/kg, ∼4.60 mg Cu per bird per day) for maximal response of eggshell thickness.

Potential Effects of Acidifier and Amylase as Substitutes for Antibiotic on the Growth Performance, Nutrient Digestion and Gut Microbiota in Yellow-Feathered Broilers.

This study was conducted to evaluate the effects of acidifier (benzoic acid, BA), amylase (AL) and their combination as substitutes for antibiotics on growth performance, antioxidation, nutrient digestion and gut microbiota of yellow-feathered broilers. A total of 1440 twenty-one-day-old broilers were randomly allocated to six treatments. Broilers in the control group (CON) were fed a basal diet, whereas birds in the other five groups were fed the basal diet supplemented with antibiotic (zinc bacitracin, AT, 40 mg/kg), BA (2000 mg/kg), low level AL (AL-L, 300 mg/kg), high level AL (AL-H, 500 mg/kg) and the combination of AL-H and BA (BA+AL-H). The experimental animals were killed at the end of the trial (21 day-63 day) then blood samples were collected from two birds per pen. Bird weight, feed intake and survival rate were recorded on pen basis. Growth performance was not significantly influenced by AT, BA, AL-L, AL-H or BA+AL-H. Plasma uric acid (UA) was decreased from CON by all treatments; the activity of AKP in plasma was also lowered by AT, BA, AL-H and BA+AL-H. Plasma activity of LDH was reduced by BA. In the jejunal mucosa, Na+K+-ATP activity was increased by BA, AL-L, AL-H and BA+AL-H. Mucosal activities of T-AOC and CAT were increased with AL-L and AT supplementation, respectively. Additionally, the relative abundance of Escherichia coli (E. coli) in the cecal contents was reduced by BA+AL-H and, with the exception of AL-H, all treatments increased the relative abundance of Lactobacillus. In conclusion, dietary AT, BA, AL-L, AL-H or BA+AL were effective in improving the antioxidant capacity, nutrient digestion and gut microbiota composition. No significant differences were observed in the tested variables between AT and other treatments, indicating that BA, AL and their combination may be alternatives to dietary inclusion of zinc bacitracin. Dietary addition of 500 mg/kg AL and 2000 mg/kg BA was an optimum supplementation dose.

Effects of dietary iron on reproductive performance of Chinese Yellow broiler breeder hens during the egg-laying period.

The objective of this study was to investigate the effects of dietary iron (Fe) on reproductive performance of Chinese Yellow broiler breeder hens during the egg-laying period. A total of 480, 55-wk-old hens were balanced for laying rate and then randomly allotted into 5 groups, each with 6 replicates (8 cages for each replicate with 2 birds per cage). The trial was for 10 wk. Birds were fed diet with 44, 58, 72, 86, or 100 mg/kg Fe contained feed. Laying performance, biochemical indices and reproductive hormones in plasma, egg quality, ovarian and oviductal variables, tibial breaking strength, and hatching performance were determined. The key performance variables hematocrit, hatchability of live embryos, and tibial breaking strength were selected for analysis by quadratic polynomial (QP) and broken-line (BL) regressions to better determine optimal dietary Fe level. Qualified egg (excluding those with double-yolk, soft-shell, cracked, very small malformed, etc.) rate tended to decrease with the lowest and highest dietary Fe levels. Hematocrit was affected (P = 0.003) by dietary Fe, along with linear (P = 0.017) and quadratic (P = 0.002) effect. There was a significant effect (P = 0.034) of dietary Fe level on tibial breaking strength of breeder hens with a quadratic (P = 0.044) effect. Breeder hens fed inadequate (44 mg/kg diet) or excess (100 mg/kg) Fe both had lower (P < 0.05) tibial breaking strength compared to that of hens fed 86 mg/kg Fe. Hatchability of live embryos was affected (P = 0.004) by diet; with both linear (P = 0.014) and quadratic (P = 0.001) effects. Maximal hatching of live embryos occurred with diets of breeder hens containing 72 mg/kg Fe. From the QP and BL models fitted to hematocrit, tibial breaking strength, and hatchability variables, the optimal dietary Fe level for Chinese Yellow broiler breeder hens in the laying period was 70-90 mg/kg. The daily Fe fed (allowance) was about 8-11 mg.

Effects of maternal and dietary vitamin A on growth performance, meat quality, antioxidant status, and immune function of offspring broilers.

The aim of this study was to evaluate the effects of maternal and dietary vitamin A (VA) level on growth performance, meat quality, antioxidant status, and immune function of offspring broilers. Chinese yellow-feathered breeder hens were fed a basal diet supplemented with 0, 5,400, 10,800, and 21,600 IU/kg VA for 8 wk, with 6 replicates of 22 hens per replicate. Then the offspring hatched from each of the 4 maternal groups were fed a basal diet supplemented with 0 or 5,000 IU/kg VA for 63 D. Overall, there were 8 treatment combinations, each with 6 replicate pens of 20 birds. Results showed that (1) providing VA in offspring diets increased final body weight (FW), average daily gain, and average daily feed intake but reduced feed-to-gain ratio and mortality of offspring broilers (P < 0.05), whereas maternal provision of VA did not significantly affect the growth performance and mortality of offspring broilers. Maternal or offspring VA did not affect proportion of breast or thigh muscle (P > 0.05). (2) Maternal feeding with 21,600 IU/kg VA increased (P < 0.05) pH 24 h postmortem of breast muscle, compared with those without maternal supplication of VA. Dietary provision of 5,000 IU/kg VA in the posthatching diet decreased (P < 0.05) drip loss, yellowness (b∗) value and lightness (L∗) value, and increased shear force and pH of breast muscle compared with those without dietary VA supplication. (3) Maternal or offspring VA did not affect the activities of total superoxide dismutase and glutathione peroxidase (GSH-Px) or the content of malondialdehyde; however, there was a significant interaction (P < 0.05) between maternal and offspring VA on the activity of GSH-Px in serum. (4) Dietary provision of 5,000 IU/kg VA increased (P < 0.05) the weight proportion of liver and bursa of fabricius, whereas maternal feeding with 21,600 IU/kg VA increased the hatchling BW. Maternal feeding with 5,400 and 21,600 IU/kg VA decreased (P < 0.05) splenic interferon-γ (IFN-γ) transcripts and increased (P < 0.05) those of interleukin-2 (IL-2) in the progeny. There were interactions (P < 0.05) between maternal and offspring VA on splenic IL-2, IL-1ß, and IFN-γ expression. In summary, maternal and offspring provision of VA both had influence on meat quality and immune function in progeny broilers. Dietary VA increased growth performance, whereas the maternal VA affected the initial body weight of progeny when hatched, but the difference in performance caused by maternal VA level was able to be eliminated by dietary VA supplementation. Therefore, offspring provision had greater importance than maternal VA in the production; however, both should be considered in broiler nutrition to achieve good meat quality and immune status of broilers.

Effects of Dietary Iron Level on Growth Performance, Immune Organ Indices and Meat Quality in Chinese Yellow Broilers.

The objective of three trials was to investigate the effects of dietary Fe on growth performance, immune organ indices and meat quality of Chinese yellow broilers during the whole growth period. A total of 1440 1-day-old, 1440 22-day-old, and 1080 43-day-old Lingnan yellow male broilers were randomly assigned to one of six dietary treatments with six replicates per treatment (40 birds per replicate for both 1 to 21 d and 22 to 42 d, 30 birds for 43 to 63 d). Additional Fe (0, 20, 40, 60, 80, and 100 mg/kg) was added as FeSO4 • H2O to the three basal diets (calculated Fe 50 mg/kg, analyzed 48.3, 49.1, 48.7 mg/kg, respectively). The calculated final dietary Fe concentrations in Starter, Grower and Finisher phases were 50, 70, 90, 110, 130, and 150 mg/kg. The results showed that average daily gain (ADG), average daily feed intake (ADFI) and feed conversion rate (FCR) of the broilers were not influenced by the different levels of Fe (p> 0.05). Weight indices of the spleen, thymus and bursa of Fabricius were not influenced (p > 0.05) by the different levels of Fe during three 21-day experimental periods. Hematocrit, and Fe contents of the liver and kidney were not affected by different levels of Fe (p> 0.05). The diet with 150 mg/kg of Fe increased the a* (relative redness) value of breast muscle compared to the 50 and 70 mg/kg diets at 24 h post mortem (p< 0.05). The diet with 90 mg/kg Fe increased the pH of breast muscle compared to broilers fed 50 or 150 mg/kg Fe (p < 0.05) 45 min after slaughter. The diet with 90 mg/kg Fe decreased drip loss of breast muscle compared to 150 mg/kg Fe (p< 0.05). These data suggest that feeding yellow-feathered broilers on a conventional corn-soy based diet satisfies their requirements without additional Fe at ages 1 to 21, and 22 to 42 d, while 90 mg/kg in the finisher phase improved meat quality, and from the QP (quadratic polynomial) models of the key meat quality variables, pH of breast muscle and drip loss of breast muscle, the optimal dietary Fe level was 89 to 108 mg/kg, and daily Fe fed allowance was 11 to 13 mg in the finisher phase (43 to 63 d).

Influence of Mushroom Polysaccharide, Nano-Copper, Copper Loaded Chitosan, and Lysozyme on Intestinal Barrier and Immunity of LPS-mediated Yellow-Feathered Chickens.

This study investigated the influence of dietary supplementation with some antibiotic alternatives on growth performance, intestinal barrier, and immunity of lipopolysaccharide (LPS) challenged chicks. Wenshi females, aged 4 days, were allocated randomly into eight groups, each with six replicates of 20 birds (n = 120/treatment), which received a basal diet supplemented with 0 (control), 0 (LPS), 200 mg/kg aureomycin, 50 mg/kg mushroom polysaccharide, 100 mg/kg mushroom polysaccharide, 500 mg/kg nano-copper, 300 mg/kg copper loaded chitosan, and 500 mg/kg lysozyme for 21 days. On day 18 and 20, the control birds were injected with 0.5 mL saline solution, the other treatments were injected with 0.5 mL saline containing 500 µg LPS/kg body weight (BW). The results indicated that LPS treatment reduced the BW, average daily gain (ADG), and daily feed intake (ADFI) than the controls (p < 0.05), and the antibiotic and the tested alternatives could not retrieve the normal BW, ADG, and ADFI. The tested additives reduced several negative effects of LPS; they reduced diamine oxidase activity and inflammatory mediators in plasma, jejunal mucosa, spleen and thymus, increased content of immunoglobulin in plasma and jejunal mucosa, and decreased gene expression of inducible nitric oxide synthase and Cyclooxygenase 2 in jejunal mucosa.

Modelling Methionine Requirements of Fast- and Slow-Growing Chinese Yellow-Feathered Chickens during the Starter Phase.

Two experiments were carried out to investigate the dietary methionine requirement for fast and slow-growing Chinese yellow-feathered breeds during the starter phase, based on growth variables and regression models. In Experiment 1, a total of 2880 one-day-old Lingnan chicks (fast growing breed) were used to test the methionine requirement from 1 to 21 days of age for males and females separately. Of each gender, 1440 birds were allocated into 6 dietary methionine levels (0.28%, 0.32%, 0.37%, 0.43%, 0.50% and 0.63%), each with 6 pen replicates of 40 chicks. Experiment 2 had the same design with Guangxi chicks (slow growing breed) from 1 to 30 d of age. Results indicated that significant nonlinear or quadratic responses to increasing dietary methionine levels were observed in body weight, daily gain, feed intake and feed conversion ratio of both breeds. In summary, the quadratic polynomial regression showed that the optimal methionine requirements for maximal growth performance of Lingnan chickens were 0.52-0.58% in males, 0.51% in females, and 0.53% in mixed genders. The corresponding values for Guangxi breed were 0.53% in males by quadratic polynomial regression and 0.43% in females, and 0.48% to 0.49% in mixed sexes by exponential asymptotic models.