Variations in BCO2 Coding Sequence Causing a Difference in Carotenoid Concentration in the Skin of Chinese Indigenous Chicken

Abstract

Carotenoid consumption decreases the risk of cancer, osteoporosis, or neurodegenerative diseases through interrupting the formation of free radicals. The deposition of carotenoids in chicken skin makes the skin color turn from white into yellow. The enzyme β-carotene oxygenase 2 (BCO2) plays a key role during the degradation process of carotenoids in skin. How the BCO2 affects the skin color of the chicken and whether it is the key factor that results in the phenotypic difference between yellow- and white-skin chickens are still unclear. In this research, the measurement of the concentration of carotenoids in chicken skin by HPLC showed that the carotenoid concentration in chickens with a yellow skin was significantly higher than that in white-skin chickens. Moreover, there were significant differences in BCO2 gene expression in the back skin between yellow- and white-skin chickens. Scanning the SNPs in BCO2 gene revealed a G/A mutation in exon 6 of the BCO2 gene in white and yellow skin chicken. Generally, one SNP c.890A>G was found to be associated with the chicken skin color and may be used as a genetic marker in breeding for yellow skin in Chinese indigenous chickens.