Zhaoyu Geng

Resveratrol alleviates heat stress-induced impairment of intestinal morphology, microflora, and barrier integrity in broilers

&NA; This study was to investigate the effect of resveratrol on intestinal morphology, microfloras, and barrier integrity of broilers subjected to heat stress. Two‐hundred‐seventy 21‐day‐old Cobb male broilers were randomly allocated to 3 treatment groups, each of which included 6 replicates with 15 birds per replicate. The 3 treatment groups were as follows: the control group, in which birds were exposed to thermoneutral condition (22 ± 1°C), and the heat stress group and heat stress + resveratrol (400 mg/kg) group, in which birds were exposed to cyclic heat stress (33 ± 1°C for 10 h/d from 0800 to 1800 h and 22 ± 1°C for the remaining time. Compared with birds in the control group, birds in the heat stress group exhibited decreased (P < 0.05) final body weight, average daily gain, average daily feed intake, villus height, villus height to crypt depth ratio, goblet cells numbers, populations of Lactobacillus and Bifidobacterium, and mRNA levels of mucin‐2, claudin‐1, occludin, zona occludens‐1, and E‐cadherin, and increased (P < 0.05) crypt depth, serum D‐lactic acid and fluorescein isothiocyanate dextran contents and diamine oxidase activity, and populations of Salmonella, Escherichia coli, and Clostridium. Compared with birds in the heat stress group, birds in the heat stress + resveratrol group exhibited decreased (P < 0.05) crypt depth, serum D‐lactic acid and fluorescein isothiocyanate dextran contents, and populations of Escherichia coli, and increased (P < 0.05) final body weight, villus height, villus height to crypt depth ratio, goblet cells numbers, populations of Lactobacillus and Bifidobacterium, and mRNA levels of mucin‐2, claudin‐1, occludin, and E‐cadherin. Taken together, these results indicated for the first time that dietary addition of resveratrol was effective in partially ameliorating the adverse effects of heat stress on intestinal barrier function in broilers by restoring the impaired villus‐crypt structure, modifying the profiles of intestinal microfloras, and altering the mRNA expression of intestinal tight junctions‐ and adherence junctions‐related genes.

Cold stress initiates the Nrf2/UGT1A1/L-FABP signaling pathway in chickens.

Cold stress triggers an anti-oxidative response in animals regulated by Nrf2 (nuclear factor 2-like, NFE2L2) binding to deoxyribonucleic acid-regulatory sequences near stress-responsive genes. To identify chicken Nrf2-regulated genes, 3 genetically related experimental groups (EG) with 40 Huainan partridge chickens in each group were chosen. The chickens were maintained at 20°C environmental temperature from 5 wk of age. At 6 wk of age, 10 chickens from each EG were still maintained at 20°C as control, and the other 30 chickens from each EG were exposed to 6 ± 2°C. Liver samples were collected from the control and from chickens exposed to 6 ± 2°C for 12, 24, and 72 h for co-immuno-precipitation (CoIP) analysis. Chromatin immunoprecipitation (ChIP)-sequencing experiment in liver cells treated with Dimethyl fumarate (DMF) were carried out. A de novo motif was discovered which closely matched the core Nrf2 consensus binding motif. Genes involved in de novo motif discovery were further analyzed for their enrichment in the anti-oxidative response pathway and the lipid anabolism pathway. There were 14 genes found which are related to oxidative stress. To examine the downstream factors of the 14 responsive genes, one of them, UGT1A1 (UDP glucuronosyltransferase), was further analyzed by CoIP experiment and nano LC-ESI-MS/MS analysis. It was detected that fatty acid-binding protein (L-FABP, 127 AA) might be the potential UGT1A1 downstream interaction proteins. In conclusion, it is proposed that chickens under cold stress generate anti-oxidative stress and thus trigger the Nrf2/ARE signaling pathway, which further up-regulates the expression of L-FABP to inactivate lipid peroxidation of the cell membrane and promote fatty acid storage against the cold environment.

Effect of dietary resveratrol supplementation on meat quality, muscle antioxidative capacity and mitochondrial biogenesis of broilers

BACKGROUND The naturally occurring polyphenol resveratrol has been acknowledged with many beneficial biological effects. The aim of this study was to evaluate the influence of dietary resveratrol supplementation on meat quality, muscle antioxidative capacity and mitochondrial biogenesis of broilers. One hundred and eighty 21-day-old male Cobb broilers were randomly assigned to two groups and fed on a 0 mg kg-1 or 400 mg kg-1 resveratrol-supplemented diet for 21 days. Then, chickens were slaughtered and pectoralis major muscle (PM) samples were collected for analysis. RESULTS The results showed that resveratrol not only tended to increase (P < 0.10) PM pH24h but also significantly decreased (P < 0.05) PM L*45min , pH decline, drip loss and lactate content. Meanwhile, PM total antioxidative capacity and catalase activity were significantly increased (P < 0.05) by resveratrol, while malondialdehyde content was decreased (P < 0.10). Moreover, resveratrol significantly increased (P < 0.05) PM peroxisome proliferator-activated receptor γ coactivator 1α and nuclear respiratory factor 1 mRNA levels, along with increased (P < 0.05) citrate synthase activity. CONCLUSION Resveratrol can be used as a feed additive to improve meat quality of broilers, which may be associated with improved muscle antioxidative status and mitochondrial biogenesis.

Hypothalamic transcriptome analysis reveals the neuroendocrine mechanisms in controlling broodiness of Muscovy duck (Cairina moschata)

Broodiness, one of the maternal behaviors and instincts for natural breeding in birds, is an interesting topic in reproductive biology. Broodiness in poultry is characterized by persistent nesting, usually associated with cessation of egg laying. The study of avian broodiness is essential for bird conservation breeding and commercial poultry industry. In this study, we examined the hypothalamus transcriptome of Muscovy duck in three reproductive stages, including egg-laying anaphase (LA), brooding prophase (BP) and brooding metaphase (BM). Differences in gene expression during the transition from egg-laying to broodiness were examined, and 155, 379, 292 differently expressed genes (DEGs) were obtained by pairwise comparisons of LA-vs-BP, LA-vs-BM and BP-vs-BM, respectively (fold change≥ 1.5, P < 0.05). Gene Ontology Term (GO) enrichment analysis suggested a possible role of oxidative stress in the hypothalamus might invoke reproductive costs that potentially change genes expression. KEGG analysis revealed glutamatergic synapse, dopaminergic synapse, serotonergic synapse and GABAergic synapse pathway were significantly enriched, and regulator genes were identified. Eight gene expression patterns were illustrated by trend analysis and further clustered into three clusters. Additional six hub genes were identified through combining trend analysis and protein-protein interaction (PPI) analysis. Our results suggested that the cyclical mechanisms of reproductive function conversion include effects of oxidative stress, biosynthesis of neurotransmitters or their receptors, and interactions between glucocorticoids and thyroid hormones and regulatory genes. These candidate genes and biological pathways may be used as targets for artificial manipulation and marker-assisted breeding in the reproductive behavior.

Polymorphisms in the uncoupling protein 3 gene and their associations with feed efficiency in chickens

Objective The uncoupling protein 3 (UCP3) is a member of the mitochondrial anion carrier superfamily and has crucial effects on growth and feed efficiency in many species. Therefore, the objective of the present study was to examine the association of polymorphisms in the UCP3 gene with feed efficiency in meat-type chickens. Methods Six single nucleotide polymorphisms (SNPs) of the UCP3 gene were chosen to be genotyped using matrix-assisted laser desorption-ionization time-of-flight mass spectrometry in meat-type chicken populations with 724 birds in total. Body weight at 49 (BW49) and 70 days of age (BW70) and feed intake (FI) in the interval were collected, then body weight gain (BWG) and feed conversion ratio (FCR) were calculated individually. Results One SNP with a low minor allele frequency (<1%) was removed by quality control and data filtering. The results showed that rs13997809 of UCP3 was significantly associated with BWG and FCR (p<0.05), and that rs13997811 had significant effects on BW70 and BWG (p<0.05). Rs13997812 of UCP3 was strongly associated with BW70, FI, and FCR (p<0.05). Furthermore, individuals with AA genotype of rs13997809 had significantly higher BWG and lower FCR (p<0.05) than those with AT genotype. The GG individuals showed strongly higher BW70 and BWG than AA birds in rs13997811 (p<0.05). Birds with the TT genotype of rs13997812 had significantly greater BW70 and lower FCR compared with the CT birds (p<0.05). In addition, the TAC haplotype based on rs13997809, rs13997811, and rs13997812 showed significant effects on BW70, FI, and FCR (p<0.05). Conclusion Our results therefore demonstrate important roles for UCP3 polymorphisms in growth and feed efficiency that might be used in meat-type chicken breeding programs.

Association of polymorphisms in Pit-1 gene with growth and feed efficiency in meat-type chickens

Objective The pituitary specific transcription factor-1 (Pit-1) gene is responsible for pituitary development and growth hormone expression and is regarded as a pivotal candidate gene for growth and production in chickens. Therefore, the aim of this study was to investigate the association of Pit-1 polymorphisms with growth and feed efficiency traits in yellow meat-type chickens. Methods In the present study, five single nucleotide polymorphisms (SNPs) of Pit-1 were selected and genotyped by high-throughput matrix-assisted laser desorption-ionization time-of-flight mass spectrometry in 724 meat-type chickens. Results Association analysis showed that rs13687126 of Pit-1 was strongly associated with body weight gain (BWG) and feed intake (FI) (p<0.05), and that rs13687128 was significantly correlated with body weight at 70 days of age (BW70), BWG and feed conversion ratio (FCR) (p<0.05). SNP rs13905622 was strongly related to BW70 and FCR (p<0.05). Furthermore, birds with the GG genotype of rs13687126 had larger BWG and FI than those with the AG genotype (p<0.05). Individuals with the TT genotype of rs13687128 were significantly higher BW70 and BWG than those of the CT and CC genotype, while FCR was just the opposite (p<0.05). For rs13905622, the AA chickens showed strongly larger BW70 and lower FCR compared with the AT and TT chickens (p<0.05). Additionally, an ACA haplotype based on rs13687126, rs13687128, and rs13905622 had significant effects on BW70 and FCR (p<0.05). Conclusion Our studies thus provide crucial evidence for the relationship between polymorphisms of Pit-1 and growth and feed efficiency traits which may be useful for meat-type chicken breeding programs.