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1. Chicken primary myoblasts (CPMs) are precursors that form muscle fibres. The proliferation and differentiation of CPMs is an essential stage in muscle development. Previous RNA-seq analysis showed that phosphoglycerate dehydrogenase ( PHGDH ) is a differentially expressed gene in chicken muscle tissue at different growth stages. Therefore, the following study explored the effect of PHGDH on the proliferation and differentiation of CPMs.2. The effect on the proliferation of CPMs by RT-qPCR, CCK-8, and EdU assays after the overexpression and knockdown of PHGDH was evaluated. RT-qPCR, western blotting, and indirect immunofluorescence were used to detect the effect of PHGDH on the differentiation of the CPMs. The expression was observed at different time points for differentiation induced by the CPMs.3. The results showed that PHGDH significantly promoted proliferation and differentiation in CPMs. The results showed that overexpression of PHGDH significantly upregulated CPM proliferation, while knockdown had the opposite effect. Marker genes showed that overexpression of PHGDH significantly upregulated the expression of P21, MYOG and MYOD genes, significantly downregulated the expression of the MSTN gene and promoted the expression of the MYHC protein. In contrast, PHGDH knockdown had the opposite effect.4. Desmin immunofluorescence analysis of myotube differentiation in primary myoblasts showed that overexpression of PHGDH significantly increased the area of myotube differentiation and promoted the proliferation and differentiation of myoblasts. Knockdown of PHGDH had the opposite effect.5. In summary, PHGDH was shown to play a positive role in regulating myoblast proliferation and differentiation. This provides a theoretical basis for further analysis of the regulatory mechanism of the PHGDH gene in chicken muscle development and for improving poultry production.

1. The goals of this study were to analyse the changes in microbiota composition of chilled chicken during storage and identify microbial biomarkers related to meat freshness.2. The study used 16S rDNA sequencing to track the microbiota shift in chilled chicken during storage. Associations between microbiota composition and storage time were analysed and microbial biomarkers were identified.3. The results showed that microbial diversity of chilled chicken decreased with the storage time. A total of 27 and 24 microbial biomarkers were identified by using orthogonal partial least squares (OPLS) and the random forest regression approach, respectively. The receiver operating characteristic (ROC) curve analysis indicated that the OPLS regression approach had better performance in identifying freshness-related biomarkers. The multiple stepwise regression analysis identified four key microbial biomarkers, including Streptococcus, Carnobacterium, Serratia and Photobacterium genera and constructed a predictive model.4. The study provided microbial biomarkers and a model related to the freshness of chilled chicken. These findings provide a basis for developing detection methods of the freshness of chilled chicken.

The depletion of amoxicillin (AMO) and its major metabolites, amoxicilloic acid (AMA) and amoxicillin-diketopiperazine-2',5'-dione (DIKETO) in the albumen, yolk and whole egg was studied after the oral dose of AMO (25 and 50 mg/kg body weight) to laying hens once per day for five consecutive days. Egg samples were prepared by a simple liquid-liquid extraction procedure with acetonitrile and saturated methylene chloride and analysed using liquid chromatography-tandem mass spectrometry. The results showed that AMO, AMA and DIKETO residues were mainly distributed in the yolk, where particularly high concentrations of AMO and DIKETO were found, whereas the albumen contained high concentrations of AMA. This distribution suggested that AMO and DIKETO were depleted slowly in yolk, whereas AMA was depleted slowly in albumen. The amount of AMO residue positively correlated with the dose, and the theoretical withdrawal times, which were calculated based on the residue level falling below a safe limit, were 5.21 and 7.67 days at AMO doses of 25 and 50 mg/kg, respectively. Moreover, the theoretical withdrawal times for all residues in the whole egg were 8.00 and 9.11 days at doses of 25 and 50 mg/kg, respectively. Our findings suggested that 9 days was an appropriate withdrawal time for the use of AMO in laying hens., (© 2016 John Wiley & Sons Ltd.)

Growth traits are important economic traits in broiler chicken production. AluI and Hin1I loci are two restriction sites, which are respectively located in exons 2 and 3 of the IGF-1R gene. These two loci are significantly related to the growth traits in Jinghai Yellow chickens. In this study, a correlation analysis was performed between these two loci and the growth traits of Bian chickens. The results showed a G376A mutation at the AluI site and a C919A mutation at the Hin1I site, which respectively resulted in three genotypes AA, AB, and BB in exon 2 and three genotypes CC, CD, and DD in exon 3. Correlation analysis showed that the female Bian chickens with the AA genotype of the AluI locus had higher body weights than those with the AB genotype (P < 0.05) at 8, 14, 16, and 18 weeks; individuals with CD genotype of Hin1I locus had higher body weights at 6, 8, 10, 12, and 14 weeks compared to the CC genotype (P < 0.05 or P < 0.01). Combined genotypes analysis showed that at the age of 8, 14, 16, and 18 weeks, the body weight of AACC genotype combination was higher than that of the ABCC genotype combination (P < 0.05); at the age of 6, 8, 12, 14, 16, and 18 weeks, the AACD genotype combination had higher (P < 0.05 or P < 0.01) body weight than that of the ABCC genotype.

Reproductive traits have long been studied and have an important influence on chicken breeding. To identify quantitative trait loci affecting reproductive traits, a genome-wide analysis of a Chinese chicken breed was performed to analyze age at first egg body weight at first egg, first egg weight, egg weight at the age of 300 days, egg weight at the age of 462 days, egg number at the age of 300 days, egg number between the ages of 300 and 462 days and egg number at the age of 462 days. Nineteen SNPs related to reproductive traits were presented (P < 1.80E-6). Nine of the 19 SNPs had a significant effect on BWF, six SNPs were significantly associated with egg weight, and four SNPs were significantly associated with egg number. These SNPs were located near to or in 17 genes including FAM184B, HTT, KCNH7, CDC42BPA, KCNIP4, GJA5, CBFB, and GPC6. The present results may be beneficial for reproductive research and may be used in marker-assisted selection in future studies. These results could potentially benefit further breeding programs, especially in Jinghai Yellow Chicken.

The growth trait is important in poultry production. We analyzed the association between single nucleotide polymorphisms (SNPs) in the Myf5 and MyoG gene and Bian chicken growth traits. SNPs in candidate genes of the Bian chickens were detected by the polymerase chain reaction-single strand conformation polymorphism method. Two mutation loci and six genotypes were identified in each candidate gene. In terms of growth traits, least square analysis showed that the FF genotype of the MyoG was the advantage genotype and the IJ genotype of the Myf5 was the disadvantage genotype for growth trait in Bian chicken. Correlation analysis suggested that the different combination genotypes between Myf5 and MyoG genes had a significant effect on growth traits in Bian chickens. The result suggested that MyoG and Myf5 genes can be used in marker-assisted selection for improving the growth trait in Bian chicken., Competing Interests: The authors declare no conflict of interest.

Body weight is one of the most important economic traits in the poultry industry. In the present study, a custom SNP Beadchip was used to analyze the association between those 15 SNPs and 12 growth traits of Jinghai yellow chickens, and other important genetic parameters were also calculated and analyzed. The results indicated that nine of the 15 SNPs were associated with growth traits in Jinghai yellow chickens (P < 0.05), and the identified SNPs were also in linkage disequilibrium. Five of the nine identified SNPs were mainly associated with all of the growth traits, which indicated that those five SNPs might have significant influence on Jinghai yellow chicken growth traits. Polymorphism information content (PIC) analyses indicated that five of the nine SNPs exhibited moderate polymorphism (0.25 < PIC < 0.5), which reflected intermediate genetic diversity. Six candidate genes surrounding the significant SNPs were obtained and subjected to Gene Ontology annotation analyses and pathway analyses. The functions of six important candidate genes (SETDB2, ATP7B, INTS6, KPNA3, DLEU7, and FOXO1A) were discussed. The present study provided basic data for marker-assisted selection in Jinghai yellow chickens.

To identify molecular markers and candidate genes associated with reproductive traits, a genome-wide analysis was performed in Jinghai Yellow Chickens to analyze body weight at first oviposition (BWF), age at first oviposition (AFE), weight of the egg at first oviposition (FEW), egg weight at the age of 300 days (EW300), number of eggs produced by 300 days of age (EN300), egg hatchability (HA) and multiple selection index for egg production (MSI). The results showed that seven single nucleotide polymorphisms (SNPs) were associated with reproductive traits (P<1.80E-6, Bonferroni correction). The P-values of the seven SNPs were 5.62E-10, 3.45E-08, 9.76E-07, 8.90E-07, 1.12E-06, 1.42E-07 and 1.48E-07, respectively. These SNPs were located in close proximity to or within the sequence of the five candidate genes, including FAM184B, TTL, RGS1, FBLN5 and PCNX. An additional 46 SNPs that could be associated with reproductive traits were identified (P<3.59E-5, Bonferroni correction). Identification of the candidate genes as well as genome-wide SNPs that may be associated with reproductive traits will greatly advance the understanding of the genetic basis and molecular mechanisms underlying reproductive traits and may have practical significance in breeding programs for the improvements of reproductive traits in the Jinghai Yellow Chicken., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Growth is one of the most economically important traits in the poultry industry. In this study, we identified single-nucleotide polymorphisms (SNPs) and candidate genes associated with growth traits of the Jinghai Yellow chicken. Genome-wide association studies were conducted using the Illumina 60 K SNP Chicken array to genotype 400 Jinghai Yellow chickens. For each bird, the body weights at hatching and at 2, 4, 6, 8, 12, 14, and 16 weeks were recorded. The SNPs that were significantly associated with the growth traits were identified using the general linear regression model. The results revealed a total of 18 SNPs that reached Bonferroni genome-wide significance (P < 1.80E-6). Three proximal genes (BTRC, NLK, and NF1) were found to participate in the Wnt-signaling pathway and mitogen-activated protein kinase signaling pathway. Haplotype analysis identified 19 significant haplotypes and identified a region 152.4-156.3M on GGA1 affecting 3 growth traits (BW4, BW14, and BW16). These results may help identify the exact locations of body weight quantitative trait loci on a genome level and indicate variants that can be used for subsequent investigations for Jinghai Yellow chicken.

The gonadotropin-releasing hormone (GnRH) plays an important role in the control of reproductive functions. Recent studies have reported the occurrence of GnRH molecular variants in numerous species. In this study, the GnRH1 gene from Jinghai yellow chicken was cloned by reverse transcriptase-polymerase chain reaction and transformed into BL21 (DE3) competent cells. The GnRH1 gene and amino acid sequences were subjected to bioinformatic analyses. The GnRH1 gene nucleotide sequence was discovered to be 352 bp long, containing a coding, promoter, and section of the 3'-regions. The GnRH1 gene shared 93, 81, 54, 58, 61, 76, 76, 59, 76, and 66% sequence identity with Meleagris gallopavo, Columba livia, Homo sapiens, Bos taurus, swines, Capra hircus, Ovis aries, Pantholops hodgsonii, Equus caballus, and Rattus norvegicus, respectively. The GnRH1 gene showed conserved domains. The GnRH1 protein was a secreted protein comprising 92 amino acids, with a molecular weight of 10205.6 Da and a theoretical pI of 5.67. Most of the amino acid residues were observed to be hydrophilic, indicating water solubility. The predicted secondary structures of proteins included α-helices (h; 23.08%), β-extensions (e; 10.92%), and random coils (c; 66.0%). The successful construction of prokaryotic expression vector pET32a-GnRH1 was confirmed by restriction and sequence analysis. SDS-PAGE analysis showed the successful expression of recombinant plasmid in Escherichia coli BL21 (molecular weight = 25-28 kDa). Larger quantities of protein were expressed in supernatant, indicating greater expression in soluble form. Western blot analysis confirmed the expression of the target protein.

1. The objective of this study was to verify the functional effects of the c.234G>A substitution in the myostatin (MSTN) gene and ascertain the mechanism by which the variant affects growth traits in the Bian chicken. 2. The c.234G>A substitution was detected by PCR-RFLP analysis in the 7th-generation Bian chickens and three genotypes (AA, AG and GG) were identified. Results showed that the substitution was significantly associated with all studied growth traits, except first-d-weight, in female Bian chickens. 3. Based on these results, the substitution was used in gene-assisted selection for growth traits and thus fast-growth (AA genotype) and slow-growth (GG genotype) lines were successfully established. Significant differences in growth traits were detected between the fast-growth and slow-growth lines from 6 to 16 weeks of age. Furthermore, all slaughter traits, except leg muscle rate, were significantly different between the fast-growth and slow-growth lines. 4. Expression analysis showed that the relative expression level of MSTN in chickens with GG and AG genotypes were significantly higher than that in chickens with an AA genotype, both in breast and leg muscle. Chickens in the slow-growth line had significantly higher relative expression level of MSTN compared to chickens in the fast-growth line, both in breast and leg muscle. 5. The results suggest that the c.234G>A substitution in the myostatin (MSTN) gene negatively regulates the expression of MSTN in the Bian chicken and that it may be used in marker-assisted selection to accelerate the chicken breeding process.

Myostatin (MSTN), or growth and differentiation factor 8 (GDF8), is a member of the transforming growth factor (TGF)-β superfamily. This family functions as a negative regulator of skeletal muscle development and growth in mammals. Single-nucleotide polymorphisms in exon 1 of the Bian chicken myostatin gene were detected by polymerase chain reaction-restriction fragment length polymorphism. A mutation (c.234G>A) in exon 1 was found. Female Bian chickens of genotypes AA and GA had significantly higher body weights than those of genotype GG (P < 0.05 or P < 0.01) from 6 to 18 weeks of age. These results suggested that the mutation c.234G>A in exon 1 could be used as a genetic marker for Bian chicken growth traits., (© 2011 The Authors, Animal Genetics © 2011 Stichting International Foundation for Animal Genetics.)

In our research, signal transducer and activator of transcription 5b (STAT5b) gene was studied as candidate gene associated with body weight and reproductive traits of Jinghai Yellow chicken. Single nucleotide polymorphisms (SNPs) of STAT5b gene were examined in both Jinghai Yellow chicken and three reference chicken populations including the Bian, Youxi and Arbor Acre chickens. Two SNPs (C-1591T and G-250A) were detected in the 5' flanking region of STAT5b gene. Association indicated that the C-1591T mutation is significantly associated with age at fist egg, The G-250A mutation is significantly related with hatch weight and body weight at 300 days. Additionally four STAT5b haplotypes (H1, CG; H2, TG; H3, AC and H4, TA) and their frequency distributions were estimated using the phase program. Diplotype H3H4 is dominant for 8, 16 week-age-weight and body weight at first egg. Thus STAT5b gene may be served as a potential genetic marker for growth and reproduction traits evaluation of the Jinghai Yellow chicken. This study will provide valuable information for the protection and breeding of Jinghai Yellow chicken.