Integrated transcriptome and proteome revealed that the declined expression of cell cycle-related genes associated with follicular atresia in geese.

BACKGROUND: Geese exhibit relatively low reproductive performance, and follicular atresia is an important factor that restricts the egg production of geese. Systematic analysis of the regulation of follicle atresia in geese through transcriptome and proteome levels could provide meaningful information on clarifying the mechanism of follicle atresia in poultry. RESULT: The granulosa cell layer was loose, disintegrated and showed apoptosis in atretic follicles and remained intact in normal follicles. The hormone levels of FSH and LH were significantly decreased in the atresia follicles compared to the normal follicles (P < 0.05). A total of 954 differentially expressed genes (DEGs, 315 increased and 639 decreased) and 161 differentially expressed proteins (DEPs, 61 increased and 100 decreased) were obtained in atresia follicles compared to normal follicles, of which, 15 genes were differentially expressed in both transcriptome and proteome. The DEGs were mainly enriched in sodium transmembrane transport, plasma membrane, and transmembrane transporter activity based on the GO enrichment analysis and in the cell cycle pathway based on the KEGG enrichment analysis. The DEPs were mainly enriched in localization, lysosome, and phospholipid-binding based on the GO enrichment analysis. Candidate genes Smad2/3, Smad4, Annexin A1 (ANXA1), Stromelysin-1 (MMP3), Serine/threonine-protein kinase (CHK1), DNA replication licensing factor (MCM3), Cyclin-A2 (CCNA2), mitotic spindle assembly checkpoint protein (MAD2), Cyclin-dependent kinase 1 (CDK1), fibroblast growth factor 12 (FGF12), and G1/S-specific cyclin-D1 (CCND1) were possibly responsible for the regulation of atresia. CONCLUSION: The cell cycle is an important pathway for the regulation of follicular atresia. Sodium outflow and high expression of MMP3 and MMP9 could be responsible for structural destruction and apoptosis of follicular cells.

A Novel in Duck Myoblasts: The Transcription Factor Retinoid X Receptor Alpha (RXRA) Inhibits Lipid Accumulation by Promoting CD36 Expression.

Retinoid X receptor alpha (RXRA) is a well-characterized factor that regulates lipid metabolism; however, the regulatory mechanism in muscle cells of poultry is still unknown. The overexpression and the knockdown of RXRA in myoblasts (CS2 cells), RT-PCR, and western blotting were used to detect the expression levels of genes and proteins related to PPAR-signaling pathways. Intracellular triglycerides (TGs), cholesterol (CHOL), and nonesterified free fatty acids (NEFAs) were detected by the Elisa kit. Fat droplets were stained with Oil Red O. The double-fluorescein reporter gene and chromatin immunoprecipitation (CHIP) were used to verify the relationship between RXRA and candidate target genes. The RXRA gene was highly expressed in duck breast muscle, and its mRNA and its protein were reduced during the differentiation of CS2 cells. The CS2 cells, with the overexpression of RXRA, showed reduced content in TGs, CHOL, NEFAs, and lipid droplets and upregulated the mRNA expression of CD36, ACSL1, and PPARG genes and the protein expression of CD36 and PPARG. The knockdown of RXRA expression in CS2 cells enhanced the content of TGs, CHOL, NEFAs, and lipid droplets and downregulated the mRNA and protein expression of CD36, ACLS1, ELOVL6, and PPARG. The overexpression of the RXRA gene, the activity of the double-luciferase reporter gene of the wild-type CD36 promoter was higher than that of the mutant type. RXRA bound to -860/-852 nt, -688/-680 nt, and -165/-157 nt at the promoter region of CD36. Moreover, the overexpression of CD36 in CS2 cells could suppress the content of TGs, CHOL, NEFAs, and lipid droplets, while the knockdown expression of CD36 increased the content of TGs, CHOL, NEFAs, and lipid droplets. In this study, the transcription factor, RXRA, inhibited the accumulation of TGs, CHOL, NEFAs, and fat droplets in CS2 cells by promoting CD36 expression.

Effect of ellagic acid and mesocarp extract of Punica granatum on productive and reproductive performances of laying hens.

In the present study, we determined the potential effects of ellagic acid and mesocarp extract of Punica granatum on the productive and reproduction performance of laying hens. Five treatment groups were setup: (1) control group (without ellagic acid), (2) 50 mg of ellagic acid, (3) 100 mg of ellagic acid, (4) 200 mg of ellagic acid, and (5) mesocarp extract of P. granatum. All the groups were investigated for feed intake, body weight, egg production, egg quality, fertility, hatchability, antioxidant status of serum and liver, lipid peroxidation, and antibacterial activities. Egg production, feed intake, and bodyweight were significantly increased (p < 0.05) with 100 mg of ellagic acid and P. granatum extract while no significant effect was observed on albumen and yolk weight, yolk index, yolk color, egg-shape index, and Haugh unit. Both ellagic acid and P. granatum extract significantly improved hatchability while 100 and 200 mg/kg of ellagic acid numerically decreased fertility. Besides, ellagic acid (100 mg/kg) and P. granatum extract significantly decreased malondialdehyde concentration and increased total antioxidant capacity, glutathione peroxidase, and total superoxide dismutase in serum and liver samples of laying hens (p < 0.05). The lipid peroxidation was decreased among the treatment groups, with 100 mg of ellagic acid and P. granatum extract showed the best activity. Moreover, ellagic acid demonstrated strong killing activity against Escherichia coli and Staphylococcus aureus while it was ineffective against methicillin-resistant S. aureus. Our results conclude that ellagic acid and P. granatum promoted egg production, hatchability, and antioxidant enzyme activities of the laying hens.

Comparative Analysis of Metabolites in the Liver of Muscovy Ducks at Different Egg-Laying Stages Using Nontargeted Ultra-High-Performance Liquid Chromatography-Electrospray Mass Spectrometry-Based Metabolomics.

Liver plays an important physiological function in the synthesis of yolk materials during egg laying in birds. Liver metabolite profiles of Muscovy ducks at different egg-laying stages from the perspective of nontargeted metabolomics were analyzed in this study. Twelve Muscovy ducks were selected at pre-laying (22 weeks, TT group), laying (40 weeks, FT group), and post-laying (60 weeks, ST group) stages, resulting in 36 hepatic metabolite profiles by using ultra-high-performance liquid chromatography-electrospray mass spectrometry. A total of 324 differential metabolites (156 increased and 168 decreased) in FT as compared to the TT (FT/TT) group and 332 differential metabolites (120 increased and 212 decreased) in ST as compared to the FT (ST/FT) group were screened out. Metabolic pathways enriched in FT/TT and ST/FT groups were mainly amino acid metabolism, glycerophospholipid metabolism, nucleotide metabolism, and vitamin metabolism. The amino acid metabolism pathways were upregulated in the FT/TT group and downregulated in the ST/FT group (P < 0.05). The glutathione and ascorbic acid abundances were downregulated, and the choline abundance was upregulated during egg laying (P < 0.05). The liver provides amino acids, lipids, nucleotides, vitamins, and choline, and so on, which are essential materials for yolk precursor synthesis. The decrease in the abundance of glutathione and ascorbic acid indicates that Muscovy ducks might be in a relatively stable physiological state during egg laying.

Identification of key genes and pathways associated with feed efficiency of native chickens based on transcriptome data via bioinformatics analysis.

BACKGROUND: Improving feed efficiency is one of the important breeding targets for poultry industry. The aim of current study was to investigate the breast muscle transcriptome data of native chickens divergent for feed efficiency. Residual feed intake (RFI) value was calculated for 1008 closely related chickens. The 5 most efficient (LRFI) and 5 least efficient (HRFI) birds were selected for further analysis. Transcriptomic data were generated from breast muscle collected post-slaughter. RESULTS: The differently expressed genes (DEGs) analysis showed that 24 and 325 known genes were significantly up- and down-regulated in LRFI birds. An enrichment analysis of DEGs showed that the genes and pathways related to inflammatory response and immune response were up-regulated in HRFI chickens. Moreover, Gene Set Enrichment Analysis (GSEA) was also employed, which indicated that LRFI chickens increased expression of genes related to mitochondrial function. Furthermore, protein network interaction and function analyses revealed ND2, ND4, CYTB, RAC2, VCAM1, CTSS and TLR4 were key genes for feed efficiency. And the 'phagosome', 'cell adhesion molecules (CAMs)', 'citrate cycle (TCA cycle)' and 'oxidative phosphorylation' were key pathways contributing to the difference in feed efficiency. CONCLUSIONS: In summary, a series of key genes and pathways were identified via bioinformatics analysis. These key genes may influence feed efficiency through deep involvement in ROS production and inflammatory response. Our results suggested that LRFI chickens may synthesize ATP more efficiently and control reactive oxygen species (ROS) production more strictly by enhancing the mitochondrial function in skeletal muscle compared with HRFI chickens. These findings provide some clues for understanding the molecular mechanism of feed efficiency in birds and will be a useful reference data for native chicken breeding.

Genome-wide genetic structure and selection signatures for color in 10 traditional Chinese yellow-feathered chicken breeds.

BACKGROUND: Yellow-feathered chickens (YFCs) have a long history in China. They are well-known for the nutritional and commercial importance attributable to their yellow color phenotype. Currently, there is a huge paucity in knowledge of the genetic determinants responsible for phenotypic and biochemical properties of these iconic chickens. This study aimed to uncover the genetic structure and the molecular underpinnings of the YFCs trademark coloration. RESULTS: The whole-genomes of 100 YFCs from 10 major traditional breeds and 10 Huaibei partridge chickens from China were re-sequenced. Comparative population genomics based on autosomal single nucleotide polymorphisms (SNPs) revealed three geographically based clusters among the YFCs. Compared to other Chinese indigenous chicken genomes incorporated from previous studies, a closer genetic proximity within YFC breeds than between YFC breeds and other chicken populations is evident. Through genome-wide scans for selective sweeps, we identified RALY heterogeneous nuclear ribonucleoprotein (RALY), leucine rich repeat containing G protein-coupled receptor 4 (LGR4), solute carrier family 23 member 2 (SLC23A2), and solute carrier family 2 member 14 (SLC2A14), besides the classical beta-carotene dioxygenase 2 (BCDO2), as major candidates pigment determining genes in the YFCs. CONCLUSION: We provide the first comprehensive genomic data of the YFCs. Our analyses show phylogeographical patterns among the YFCs and potential candidate genes giving rise to the yellow color trait of the YFCs. This study lays the foundation for further research on the genome-phenotype cross-talks that define important poultry traits and for formulating genetic breeding and conservation strategies for the YFCs.

Devitalization of the immune mapped protein 1 undermines the intracellular proliferation of Toxoplasma gondii.

The intracellular protozoan Toxoplasma gondii infects approximately one-third of the world's population as well as various animals, causing toxoplasmosis. However, there remains a need to define the functions of newly identified genes of T. gondii. In the present study, a novel molecule, immune mapped protein 1 of T. gondii (TgIMP1), was devitalized by CRISPR/Cas9 system to investigate the phenotypic changes of the parasite. We found that the virulence of ΔTgIMP1 knockout strain was reduced in comparison with wild-type GT1 tachyzoites, showing a statistically decreased plaque in HFF cells and a significantly prolonged survival period of mice (P < 0.05). Moreover, the data of phenotype analyses in vitro showed a different level of the intracellular proliferation and the subsequent egress between ΔTgIMP1 and wild-type GT1 strain (P < 0.05); while no statistically significant difference was detected during the process of attachment or invasion. These results suggested that TgIMP1 is closely associated with the intracellular proliferation of this parasite.

Comparison of slaughter performance, meat traits, serum lipid parameters and fat tissue between Chaohu ducks with high- and low-intramuscular fat content.

This study was conducted to investigate the effect of intramuscular fat (IMF) on carcass traits of Chaohu ducks. Two-hundred-forty ducks were separated by sex and raised in separate pens. Slaughter performance, meat quality, and serum lipid parameters were identified. Based on IMF, samples were divided into males with high IMF (CHM) or low IMF (CLM) and females with high IMF (CHF) or low IMF (CLF). There were significant differences in the living body weight, abdominal fat ratio (%), shear force, IMF, total cholesterol (TC), high-density lipoprotein (HDL) and low-density lipoprotein (LDL) content between female and male ducks. In addition, compared with the CLM group, the shear force (p = 0.001) was significantly greater but the lightness (p = 0.006) was lower in the CHM group. TC, HDL and LDL content were also significantly higher (p = 0.033, 0.027 and 0.012, respectively) in the CHM group. The butcher ratio (0.028), eviscerating rate (0.039) and breast meat ratio (0.028) in the CHF group was significantly lower than that in CLF group, while these parameters showed no difference between CHM and CLM. In conclusion, IMF had a significantly positive correlation with subcutaneous fat and abdominal fat and was also positively correlated with TC, HDL and LDL in Chaohu ducks.

Effect of l-theanine on growth performance, intestinal development and health, and peptide and amino acid transporters expression of broilers.

BACKGROUND: l-Theanine has multiple beneficial biological activities. However, there is little information about the use of l-theanine in broiler production. Therefore, this study investigated the effect of l-theanine on growth performance, intestinal development and health, and the mRNA levels of intestinal peptide and amino acid (AA) transporters of broilers. RESULTS: Body weight and average daily gain were increased by l-theanine, whereas feed to gain ratio was decreased (quadratic, P < 0.05). Notably, the relative weight of duodenum, jejunum and ileum, villus height, villus height to crypt depth ratio, the jejunal activities of glutathione peroxidase, total antioxidant capacity, catalase and total superoxide dismutase were increased linearly and/or quadratically by l-theanine (P < 0.05), whereas crypt depth, serum d-lactic acid, and jejunal protein carbonyls and malondialdehyde content were decreased linearly and/or quadratically (P < 0.05). Moreover, l-theanine enhanced the jejunal mRNA levels of occludin, claudin-1, E-cadherin, zona occludens-1, di- and tripeptide transporter, excitatory AA transporter 3, Na+ -independent cationic AA transporter 1, Na+ -independent cationic and zwitterionic AA transporter, Na+ - and Cl- -dependent neutral and cationic AA transporter, Na+ -independent cationic and Na+ -dependent neutral AA transporter (y+LAT) 1, y+LAT2, Na+ -independent branched-chain and aromatic AA transporter, and heavy chain corresponding to the b°,+ transport system (linear and/or quadratic, P < 0.05). CONCLUSIONS: l-Theanine beneficially affected the growth performance of broilers by improving intestinal development and health, and the intestinal mRNA levels of AA and peptide transporters. Therefore, l-theanine has the potential to be a promising feed additive for broilers. © 2020 Society of Chemical Industry.

Expression of genes related to lipid transport in meat-type ducks divergent for low or high residual feed intake.

OBJECTIVE: This study examined the effects of divergence in residual feed intake (RFI) on expression profiles of key genes related to lipid transport in the liver and duodenal epithelium and their associations with feed efficiency traits in meat-type ducks. METHODS: A total of 1,000 male ducks with similar body weight (1,042.1±87.2 g) were used in this study, and their individual RFI was calculated from 21 to 42 d of age. Finally, the 10 highest RFI (HRFI) and 10 lowest RFI (LRFI) ducks were chosen for examining the expression of key genes related to lipid transport in the liver and duodenal epithelium using quantitative polymerase chain reaction. RESULTS: In the liver, expression levels of albumin (ALB), CD36 molecule (CD36), fatty acid hydroxylase domain containing 2 (FAXDC2), and choline kinase alpha (CHKA) were significantly higher in LRFI ducks than in HRFI ducks (p<0.01); negative correlations (p<0.05) between expression levels of ALB, CD36, FAXDC2, and CHKA and RFI were detected in the liver. Additionally, ALB expression was strongly positively correlated (p<0.05) with CD36, FAXDC2, CHKA, and apolipoprotein H (APOH) expression in the liver. In duodenal epithelium, we found that mRNA levels of ALB, CD36, FAXDC2, and APOH were significantly higher in LRFI ducks than in HRFI ducks (p<0.01); RFI was strongly negatively correlated (p<0.05) with ALB, FAXDC2, and APOH expression, while ALB expression was strongly positively correlated with APOH expression (p<0.01) in duodenal epithelium. Furthermore, expression levels of both ALB and FAXDC2 genes were significantly associated with feed conversion ratio and RFI in both liver and duodenal epithelium (p<0.05). CONCLUSION: Our findings therefore suggest that ALB and FAXDC2 genes might be used as potential gene markers designed to improve feed efficiency in future meat-type duck breeding programs.

NRDR inhibits estradiol synthesis and is associated with changes in reproductive traits in pigs.

Cumulus cells secreting steroid hormones have important functions in oocyte development. Several members of the short-chain dehydrogenase/reductase (SDR) family are critical to the biosynthesis of steroid hormones. NADPH-dependent retinol dehydrogenase/reductase ( NRDR), a member of the SDR superfamily, is overexpressed in pig breeds that also show high levels of androstenone. However, the potential functions and regulatory mechanisms of NRDR in pig ovaries have not been reported to date. The present study demonstrated that NRDR is highly expressed in pig ovaries and is specifically located in cumulus granulosa cells. Functional studies showed that NRDR inhibition increased estradiol synthesis. Both pregnant mare serum gonadotropin and human chorionic gonadotropin downregulated the expression of NRDR in pig cumulus granulosa cells. When the relationship between reproductive traits and single-nucleotide polymorphisms (SNPs) of the NRDR gene was examined, we found that two SNPs affected reproductive traits. SNP rs701332503 was significantly associated with a decrease in the total number of piglets born during multiparity, and rs326982309 was significantly associated with an increase in the average birth weight during primiparity. Thus, NRDR has an important role in steroid hormone biosynthesis in cumulus granulosa cells, and NRDR SNPs are associated with changes in porcine reproduction traits.

Association analysis between feed efficiency and expression of key genes of the avTOR signaling pathway in meat-type ducks.

Genes involved in the target of rapamycin (TOR) signaling pathway are implicated in nutrient translation, cell proliferation and differentiation, and anabolism, which can affect both growth and feed intake. However, the role of TOR signaling in the regulation of feed intake and feed efficiency in poultry is not clear. In the present study, a total of 1000 ducks, of similar initial weight, were chosen and transferred to individual cages to determine their residual feed intake (RFI) from the age of 21 to 42 days. Subsequently, 60 ducks, which were divided into high (HRFI) and low (LRFI) groups according to their RFI, were chosen to analyze the TOR signaling activities in the liver. The differential expression level of genes involved in the TOR signaling pathway was assayed by the real-time polymerase chain reaction. In the liver, the expression of AKT, avTOR, avLST8, and S6K1 was significantly higher in LRFI ducks than in HRFI ducks; avTOR and AKT were negatively associated with the feed conversion ratio and RFI. Furthermore, PI3K was moderately positively associated with AKT; AKT was strongly positively associated with PI3K, avTOR, avLST8, and S6K1; and avTOR was strongly positively associated with S6K1. In conclusion, the activation of avTOR signaling in the liver of LRFI ducks might be ascribed to higher energy state or more active nutrient transport (amino acids), or both, than those in the liver of HRFI ducks. The results of the present study indicate that AKT and avTOR of TOR signaling might be used as candidate genes to assess molecular regulation of feed efficiency.

Consuming egg yolk decreases body weight and increases serum HDL and brain expression of TrkB in male SD rats.

BACKGROUND: Egg yolks contain large amounts of cholesterol and are suspected to be harmful after long-term consumption. In this experiment, 63 rats were used to evaluate the effect of egg white (EW) and egg yolk (EY) supplementation on serum lipids and brain cognition. The feeding time lasted 4 weeks after a 1-week acclimation. RESULTS: Body weight was significantly higher in rats fed 132.0 g kg-1 EW and significantly lower when fed 40 g kg-1 EY (P < 0.05). Total cholesterol and low-density lipoprotein increased in rats fed 72.0 g kg-1 EW compared with rats from NC and EY groups (P < 0.05). High-density lipoprotein (HDL) was higher in rats fed 40 g kg-1 EY and decreased when fed 72.0 g kg-1 EW (P < 0.05). Rats fed a diet with EY exhibited abundant neurons in the CA1 hippocampus and complete subcellular structures. Rats fed 132 g kg-1 EW exhibited shrunken cells and swollen mitochondria. Brain-derived neurotrophic factor had constitutively low expression among groups, while tyrosine kinase B (TrkB) exhibited higher expression levels in rats fed a diet containing EY compared with other groups (P < 0.05). CONCLUSION: EY consumption reduced body weight and increased HDL levels. Diet containing EY could improve cognition through enhanced trkB expression. © 2019 Society of Chemical Industry.

Protective effects of resveratrol against high ambient temperature-induced spleen dysplasia in broilers through modulating splenic redox status and apoptosis.

BACKGROUND: Resveratrol has been shown to prevent high ambient temperature (HT)-induced spleen dysplasia, but the mechanisms of action are not clear. This study aims to examine the hypothesis that HT-induced spleen dysplasia may be associated with HT-induced oxidative stress and apoptosis, and resveratrol may activate the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway, thus reducing oxidative stress and apoptosis. RESULTS: Results showed that HT caused spleen dysplasia in broilers, reflecting the lower relative weight of the spleen (P < 0.05). Compared with birds in a normal ambient temperature group, birds in the HT group exhibited higher (P < 0.05) malondialdehyde (MDA), protein carbonyl (PC), 8-hydroxydeoxyguanosine (8-OHdG) and Bcl-2 associated X protein (Bax) content, higher Bax, caspase-3 and caspase-9 mRNA levels, and caspase-3 and caspase-9 activity, and a higher Bax/B-cell lympoma/leukemia-2 (Bcl-2) ratio, but they exhibited lower (P < 0.05) glutathione (GSH) and Bcl-2 content, and lower Nrf2, glutathione peroxidase (Gpx), MnSOD, heme oxygenase 1, glutathione reductase (GR) and Bcl-2 mRNA levels, and lower total antioxidant capacity (T-AOC), T-SOD and catalase and maganese superoixide dismutase (CAT) activity, indicating HT-induced oxidative stress and apoptosis. Compared with birds in the HT group, birds in the HT + Res group exhibited higher (P < 0.05) GSH and Bcl-2 content, higher Nrf2, CAT, MnSOD, GR and Bcl-2 mRNA levels, and higher T-AOC, T-SOD and CAT activity, but lower (P < 0.05) MDA content, and Bax and caspase-3 mRNA levels, lower caspase-3 and caspase-9 activities, and Bax/Bcl-2 ratio, indicating that resveratrol activated the Nrf2 signaling pathway and decreased apoptosis in the spleen. CONCLUSION: Resveratrol was effective in ameliorating HT-induced spleen dysplasia in broilers through the activation of the Nrf2 signaling pathway, thereby decreasing apoptosis, suggesting that resveratrol may offer a potential nutritional strategy to protect against some HT-induced detriments. © 2018 Society of Chemical Industry.

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. © 2017 Society of Chemical Industry.

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.

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.

Integrative analysis of the Pekin duck (Anas anas) MicroRNAome during feather follicle development.

BACKGROUND: The quality and yield of duck feathers are very important economic traits that might be controlled by miRNA regulation. The aim of the present study was to investigate the mechanism underlying the crosstalk between individual miRNAs and the activity of signaling pathways that control the growth of duck feathers during different periods. We therefore conducted a comprehensive investigation using Solexa sequencing technology on the Pekin duck microRNAome over six stages of feather development at days 11, 15, and 20 of embryonic development (during the hatching period), and at 1 day and 4 and 10 weeks posthatch. RESULTS: There were a total of 354 known miRNAs and 129 novel candidate miRNAs found based on comparisons with known miRNAs in the Gallus gallus miRBase. The series of miRNAs related to feather follicle formation as summarized in the present study showed two expression patterns, with primary follicle developed during embryonic stage and secondary follicle developed mainly at early post hatch stage. Analysis of miRNA expression profiles identified 18 highly expressed miRNAs, which might be directly responsible for regulation of feather development. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis suggested that in addition to Wnt and transforming growth factor (TGFß) signaling pathways, which were widely reported in response to follicle formation, another group of signaling pathways that regulate lipid synthesis and metabolism, such as the phosphatidylinositol signaling system and glycerolipid metabolism and signaling, are also responsible for follicle formation. CONCLUSION: The highly expressed miRNAs provide a valuable reference for further investigation into the functional miRNAs important for feather development. Lipid synthesis and metabolism related signaling pathways might be responsible for lipid formation on the surface of feather, and should be paid much more attention for their relation to feather quality.

Proteomic Analysis of Egg Yolk Proteins During Embryonic Development in Wanxi White Goose.

To investigate the alterations of yolk protein during embryonic development in Wanxi white goose, the egg yolk protein composition at days 0, 4, 7, 14, 18, and 25 of incubation (D0, D4, D7, D14, D18, and D25) was analyzed by two-dimensional gel electrophoresis combined with mass spectrometry. A total of 65 spots representing 11 proteins with significant abundance changes were detected. Apolipoprotein B-100, vitellogenin-1, vitellogenin-2-like, riboflavin-binding protein, and serotransferrin mainly participated in nutrient (lipid, riboflavin, and iron ion) transport, and vitellogenin-2-like showed a lower abundance after D14. Ovomucoid-like were involved in endopeptidase inhibitory activity and immunoglobulin binding and exhibited a higher expression after D18, suggesting a potential role in promoting the absorption of immunoglobulin and providing passive immune protection for goose embryos after D18. Furthermore, myosin-9 and actin (ACTB) were involved in the tight junction pathway, potentially contributing to barrier integrity. Serum albumin mainly participated in cytolysis and toxic substance binding. Therefore, the high expression of serum albumin, myosin-9, and ACTB throughout the incubation might protect the developing embryo. Apolipoprotein B-100, vitellogenin-1, vitellogenin-2-like, riboflavin-binding protein, and serotransferrin might play a crucial role in providing nutrition for embryonic development, and VTG-2-like was preferentially degraded/absorbed.

High albumen height by expression of GALNT9 and thin eggshell by decreased Ca2+ transportation caused high hatchability in Huainan partridge chicken.

Hatchability could be quite different among individuals of indigenous chicken breed which might be affected by the egg quality. In this study, hatchability was individually recorded among 800 forty-wk-old Huainan partridge chickens. The chickens were then divided into high and low hatchability groups (HH and LH group) with 50 birds in each group. Egg quality was further determined in the 2 groups. Eight birds from each group were selected for slaughtering and tissue, responsible for egg formation, collection for structure observation by staining and candidate gene expression by transcriptome analysis. The hatchability in HH was 100% and 61.18% in LH. The eggshell thickness and shell strength were significantly lower, while the albumen height and Haugh unit were significantly higher in HH group than those in LH group (P < 0.05). The magnum weight and index, and the expression of polypeptide N-acetylgalactosaminyltransferase 9 (GALNT9), which responsible for thick albumen synthesis, in HH group were also significantly higher than that of LH group (P < 0.05). Compared with the LH group, there were 702 differentially expressed genes (DEGs) in HH group, of which 402 were up-regulated and 300 were down-regulated. Candidate genes of calbindin 1 (CALB1) and solute carrier family 26 member 9 (SLC26A9), which regulate calcium signaling pathway so as to affect Ca2+ transportation, exhibited significant high and low expression, respectively, in HH group compared to those in LH group (P < 0.05). Therefore, indigenous chicken with high expression of GALNT9 in magnum to form thick albumen to provide more protein for embryo, while high CALB1 and low expression of SLC26A9 to decrease Ca2+ transportation so as to form a thinner eggshell and provide better gas exchange during embryo development.