Comparison of proteolytic-related gene expression in the skeletal muscles of layer and broiler chickens

Previous studies have shown that the muscle protein degradation rates of broiler are lower than those of layer chickens. In this study, we assessed proteolytic-related gene expression in the pectoralis muscle of layer and broiler chickens. The mRNA levels of atrogin-1/MAFbx and proteasome C2 subunit, but not those of ubiquitin, m-calpain large subunit, cathepsin B, or caspase-3, were lower in the skeletal muscle of the broilers than in the layers at 7 and 14 d of age. We infer that the lower muscle protein degradation of broilers than of layers at least partly relates to lower mRNA expression of atrogin-1/MAFbx and proteasome C2 subunit in the skeletal muscle of broilers.