Genome-wide association study of myofiber type composition traits in a yellow-feather broiler population

Meat quality is a key factor determining the economic viability of the broiler industry, particularly in native broiler breeds. Skeletal muscles contain a mixture of muscle fibers, each possessing unique physicochemical properties; the composition of myofiber types within these muscles is closely linked to meat quality. However, comprehension of the regulatory mechanisms governing this trait remains limited. Therefore, we conducted a genome-wide association study (GWAS) with a population of 400 yellow-feather broilers to explore genetic variations associated with myofiber-type composition at the genomic level. Whole-genome resequencing was employed to detect genetic variations and immunohistochemistry was used for muscle fiber typing in the sartorius muscle. We identified 1 and 18 single-nucleotide polymorphisms (SNPs) significantly and potentially associated with the proportion of slow muscle fibers, respectively, and 1 and 12 SNPs significantly and potentially associated with the area proportion of slow muscle fibers, respectively. We annotated several candidate genes, including DMD, KLF7, CREB1, EFCAB11, GADD45A, GSTT1, and GSTT1L, which are related to myofiber type composition. We also demonstrated that myofiber composition traits exhibit low-to-medium heritability, indicating potential for enhancement through genetic selection. These findings provide a crucial reference for further studies on the regulatory mechanisms of poultry meat quality and for advancing the breeding of superior-quality broiler chickens.