Abstract
Chickens are bred all over the world and have significant economic value as one of the major agricultural animals. The growth rate of commercial broiler chickens is several times higher than its Red Jungle fowl (RJF) ancestor. To further improve the meat production of commercial chickens, it is quite important to decipher the genetic mechanism of chicken growth traits. In this study, we found that broiler chickens exhibited lower levels of E3 ubiquitin ligase muscle atrophy F-box (MAFbx or Atrogin-1) relative to its RJF ancestor. As a ubiquitin ligase, Atrogin-1 plays a crucial role in muscle development in which its up-regulation often indicates the activation of muscle atrophic pathways. Here, we showed that the Atrogin-1 expression variance partly affects chicken muscle growth rates among different breeds. Furthermore, we demonstrated that the reduced expression of Atrogin-1 in broiler chickens was ascribed to a single nucleotide polymorphism (SNP), which inhibited the binding of transcription regulators and attenuated the enhancer activity. The decreased Atrogin-1 in broiler chickens suppresses the catabolism of muscle protein and preserves muscle mass. Our study facilitates the understanding of the molecular mechanism of chicken muscle development and has a high translational impact in chicken breeding.
Highlights
It has been proven that Red Jungle fowl (RJF) (Gallus gallus) is a major ancestral contributor of domestic chickens which led to a wide spectrum of breeds (Liu et al, 2006)
It is conceivable to speculate that lower levels of Atrogin-1 in Arbor Acres (AA) could be associated with lower muscle catabolism and more muscle mass
These results suggest that a mutation exist in the Atrogin-1 gene region which is selected during artificial selection for the growth traits and consequentially affects the expression of this gene
Summary
It has been proven that Red Jungle fowl (RJF) (Gallus gallus) is a major ancestral contributor of domestic chickens which led to a wide spectrum of breeds (Liu et al, 2006). During the process of human selection and breeding, chicken phenotypes vary among different breeds. Commercial chicken lines were mainly selected for the production of meat and eggs. The growth rate of ordinary domesticated chicken breeds is about six to eight times higher than that of wild chickens, which has further been improved to 5 to 10 times. Atrogin-1 Affects Chicken Muscle Mass in commercial broilers (Zuidhof et al, 2014). Profound differences in muscle growth and development exist between domesticated and wild chickens. Deciphering the genetic basis of these differences is of high importance to both biological science and the agricultural economy
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