Analysis of the Trigeminal Comb Traits in White-ear Yellow Chicken

【Objective】The study was carried out to find candidate single nucleotide polymorphisms (SNP) loci associated with the trigeminal comb traits in white-ear yellow chickens.【Method】Sixty white-ear yellow chickens were used for crossbreeding experiment and 120 white-ear yellow chickens were used for fertility rate experiment. The blood samples of eighty-two white-ear yellow chickens were collected for DNA extraction, and then genotype classification was conducted by using Illumina chicken 60 k microarrays. After using PLINK 1.90 for quality control of the genotyping results, GEMMA software was used to perform genome-wide association analysis (GWAS) on SNP and traits to find SNP loci significantly associated with trigeminal comb traits in white-ear yellow chickens.【Result】The trigeminal comb of white-ear yellow chicken showed autosomal inheritance and the egg fertility rate was not significantly different from that of the white-ear yellow chicken with single comb. 55 023 valid SNPs were obtained from the population of 82 white-ear yellow chickens and there was no significant population stratification within the population. Ten SNP loci associated with trigeminal comb were located on chromosomes 1, 2, 3, 4, 5, 12 and 14 of white-ear yellow chickens, adjacent to or located on SPRY2, NDFIP2, ITGA9, EMC2, TMEM17, EHBP1, SCAF8, TIAM2, HTT, STON2, PRKCD, RBBP6, TNRC6A and MAPK8IP3 genes.【Conclusion】Based on the GWAS analysis, it is found that 10 SNPs loci may be associated with the trigeminal comb traits in white-ear yellow chickens. These results will provide candidate molecular markers for the breeding of white-ear yellow chickens and new ideas for marker-assisted selection of local chickens

Lower Expression of SLC27A1 Enhances Intramuscular Fat Deposition in Chicken via Down-Regulated Fatty Acid Oxidation Mediated by CPT1A

Intramuscular fat (IMF) is recognized as the predominant factor affecting meat quality due to its positive correlation with tenderness, juiciness, and flavor. Chicken IMF deposition depends on the balance among lipid synthesis, transport, uptake, and subsequent metabolism, involving a lot of genes and pathways, however, its precise molecular mechanisms remain poorly understood. In the present study, the breast muscle tissue of female Wenchang chickens (WC) (higher IMF content, 1.24 in D120 and 1.62 in D180) and female White Recessive Rock chickens (WRR; lower IMF content, 0.53 in D120 and 0.90 in D180) were subjected to RNA-sequencing (RNA-seq) analysis. Results showed that many genes related to lipid catabolism, such as SLC27A1, LPL, ABCA1, and CPT1A were down-regulated in WC chickens, and these genes were involved in the PPAR signaling pathway and formed an IPA® network related to lipid metabolism. Furthermore, SLC27A1 was more down-regulated in WRR.D180.B than in WRR.D120.B. Decreased cellular triglyceride (TG) and up-regulated CPT1A were observed in the SLC27A1 overexpression QM-7 cells, and increased cellular triglyceride (TG) and down-regulated CPT1A were observed in the SLC27A1 knockdown QM-7 cells. These results suggest that lower lipid catabolism exists in WC chickens but not in WRR chickens, and lower expression of SLC27A1 facilitate IMF deposition in chicken via down-regulated fatty acid oxidation mediated by CPT1A. These findings indicate that reduced lipid catabolism, rather than increased lipid anabolism, contributes to chicken IMF deposition