Proteomics analysis of skin coloration of large yellow croaker Larimichthys crocea fed different dietary carotenoids

A proteomics analysis was conducted to investigate the effects of dietary carotenoids on the skin coloration of large yellow croaker (Larimichthys crocea) fed diets with different carotenoids for 9 weeks. The diet without carotenoids supplementation was used as the control group (CD). Based on the CD, the other four experimental diets were supplemented with 80 mg/kg of astaxanthin (AST80), 80 mg/kg of xanthophyll (X80), 40 mg/kg of astaxanthin and 40 mg/kg of xanthophyll (AST40 + X40), and 80 mg/kg of astaxanthin and 80 mg/kg of xanthophyll (AST80 + X80), respectively. Results showed that the growth performance, feed utilization, pH, water-holding capacity, and texture in the muscle of large yellow croaker were not significantly affected. No significant differences were observed in redness (a*) of dorsal skin among all the groups. Nevertheless, the redness values of ventral skin in groups with dietary carotenoids supplementation were higher than that in the control group. The yellowness (b*) of dorsal and ventral skin was significantly enhanced in dietary carotenoid-supplemented groups compared with CD group except for dorsal skin in the AST80 group. After astaxanthin or xanthophyll administration, the carotenoid contents in dorsal and ventral skin were significantly increased. After the proteomics analysis of the skin, 444 differentially expressed proteins (DEPs) and 352 DEPs have been found between AST80 and CD, and X80 and CD, respectively. The proteomics results showed that dietary carotenoids influenced the expression of myosin heavy chain, ribosomal proteins, metal iron binding related proteins, oxygen transporter activity associated proteins, lipid transport proteins and immune-related proteins. The skin coloration of large yellow croaker might be directly regulated by myosin proteins and ribosomal proteins, such as 40S ribosomal protein S21 (RPS21), 60S ribosomal protein L23a (RPL23a), RPL24 and RPL27, which were induced by astaxanthin and xanthophyll.