ABSTRACT Intramuscular fat (IMF) content is a crucial parameter for estimating meat quality. Growing evidence indicates that gene regulation plays an important role in IMF deposition. This study aimed to determine the function of Mfsd2a in chicken intramuscular preadipocytes. In the present study, high Mfsd2a mRNA levels were observed in the liver and adipose tissues of broilers. Subsequently, we synthesized small interfering RNAs to silence the expression of Mfsd2a in chicken intramuscular preadipocytes. The following results suggested that CDK2, PCNA, CCND1, CCND2 and MKI67 were inhibited, with CCK-8 and EdU assays revealing that cell proliferation was inhibited. Scratch test showed that cell migration ratios were declined. We also found that Mfsd2a silencing decreased the mRNA levels of PPARγ, RXRG and their target genes. The similar results were found in some key genes that contribute to lipid synthesis, including C/EBPα, C/EBPβ, FABP4, FASN, ACACA and ACSL1. Finally, Oil red O staining showed that IMF accumulation was blocked after Mfsd2a silencing. In conclusion, our results implied that Mfsd2a promotes the proliferation and migration of chicken intramuscular preadipocytes, as well as the differentiation and adipogenesis through PPARγ signaling pathway, which may provide a potential target to improve chicken meat quality.

ABSTRACT Myostatin (MSTN) is a negative regulator of skeletal muscle growth. In order to investigate whether there is a correlation between MSTN polymorphisms and chicken production performance, in this study, single nucleotide polymorphisms (SNPs) in MSTN gene were examined across 180 Daheng broilers by direct sequencing of PCR product, and the correlations between the genotype and body weight at the age of 1-10 weeks and carcass traits at the age of 73 day were analyzed. Five SNPs (rs313622770, rs313744840, rs316247861, rs314431084, rs317126751) of MSTN gene were identified across Daheng broiler samples, and four haplotypes were reconstructed based on the five SNPs. Results of association analysis showed that four (rs313622770, rs313744840, rs316247861 and rs317126751) of these SNPs had significant association with some growth traits (p<0.05), but there were no significant effect on carcass traits and the four SNPs were strong linkage. For rs314431084, there was no significant correlation between different genotypes and growth or carcass traits. The AA genotype of rs313622770, GG genotype of rs313744840, CC genotype of rs316247861, TT genotype of rs317126751 were good for chicken growth. Diplotypes were significantly associated with chest muscle and leg muscle weight (p<0.05). Overall, these results provide evidence that polymorphisms in MSTN gene are associated with growth traits in chicken. The SNPs in MSTN gene could be utilized as potential markers for marker-assisted selection (MAS) during chicken breeding.

ABSTRACT A complete linkage disequilibrium between the SNP (SNP B) in BCDO2 gene and the yellow skin phenotype in European domestic chicken has been reported. Here, we genotyped the reported SNPs (SNP A, SNP B, and SNP C) of the BCDO2 gene in 183 Chinese Indigenous chickens from 11 breeds/populations, including 57 yellow, 17 white, and 109 black skin chickens. The frequency of all three SNPs were significantly different between yellow and white skin chickens (p<0.01). In black skin chickens, a high frequency of the heterozygous genotype (AG) in SNP A (0.51) and SNP B (0.48) was observed. A total of three haplotypes (AAA, AGA, and GAA) from these three SNPs were obtained. Frequencies of the proposed yellow skin-associated haplotype AGA in yellow skin, white skin, and black skin chickens were 0.81, 0.35, and 0.56, respectively. The results showed that the yellow skin phenotype of the evaluated birds has not been under selection, and that the BCDO2 gene in black skin chickens, evolutionally may undergo a transition phase from yellow to white skin chicken. We concluded that, the SNPs of BCDO2 gene not only can be used to determine whether the chicken was subjected to selection, but may also be used as a marker when selecting for the preferred skin color in chicken breeding programs.