L-arginine, matters for skin health of leopard coral grouper (Plectropomus leopardus)

Abstract

An 8 weeks feeding trial was conducted in leopard coral grouper to observe the effects of dietary arginine (Arg) level on growth and skin health about development, pigmentation, antioxidant ability, immune capacity. Fish were feed five iso-lipidic and iso-proteic diets containing the Arg 2.4%, 2.9%, 3.4%, 3.9%, 4.4%, respectively. Results shown that the optimal dietary Arg value for best growth of leopard coral grouper was 3.72% of dry matter (corresponding to 6.73% of dietary protein) based on weight gain rate. The epidermis thickness of back skin and abdomen skin in Arg3.4, Arg3.9 and Arg4.4 groups was significantly higher than Arg2.4 and Arg2.9 groups. The SOD, carotene and astaxanthin in Arg4.4 group were significantly higher than Arg2.4 and 2.9 groups. Key genes in nicotinate and nicotinamide metabolism, gluconeogenesis, pentose phosphate, glutathione synthesis and ceramide synthesis pathways were significantly upregulated in Arg3.4 than Arg2.4 group, the synthesis genes of immune factors were significantly upregulated in Arg3.4 than Arg2.4 group. Suitable dietary Arg level can promote the morphological development, improve the antioxidant ability, enhance the immune capacity and reduce the consumption of pigment of skin. The results supported that Arg is an effective skin health enhancer for leopard coral grouper.