Roles of arginine in fish nutrition and health: insights for future researches

Amino acids are important molecules in fish nutrition with critical roles in protein synthesis, immune function and health. Among the essential amino acids, arginine is one of the functional amino acids in animals. Arginine requirement in fish ranges between 3.0 and 8.1% of dietary protein. The amino acid involves in ureagenesis, immune function, antioxidant defence, somatotropic axis, stress responses and ammonia detoxification in fish. To have an extended insight about the current knowledge of arginine effects in fish, this article reviewed available data on arginine effects in different fish species. It covers variations in arginine requirements of different fish species, interaction of arginine with lysine and glutamine, modulation of ureagenesis and ammonia detoxification, modulation of insulin and growth hormone responses, cortisol response, modulation of antioxidant system, immune responses and disease resistance. This review indicates that rearing conditions and dietary ingredients may affect fish arginine requirement. In addition, there is a need for further data about the antioxidant effects of arginine under oxidative condition, its immunostimulant effects under pathogenic challenge, mechanisms of ammonia detoxification and cortisol response by arginine in different fish species.