Dietary taurine improves antioxidant and lysozyme activity, carbohydrate-related metabolism, and digestive genes expression of longfin yellowtail (Seriola rivoliana).

Taurine is an amino acid widely present in animal tissues. Recent research has highlighted the importance of including taurine in the diet of various commercially relevant species. This study evaluated the impact of taurine supplementation in the diet of Seriola rivoliana on the activity of antioxidant enzymes, lysozyme, and the expression of metabolic-related genes in different tissues. Three experimental diets were designed with 0% (Control), 1%, and 2% of taurine concentrations, administered over 60 days. The results indicated that taurine supplementation significantly improved the activity of antioxidant enzymes such as catalase (CAT), superoxide dismutase (SOD), and myeloperoxidase (MPO) in the liver and plasma. Additionally, an increase in lysozyme (LZM) activity was observed in mucus and plasma of the fish. Regarding gene expression, the 2% taurine supplementation significantly increased the expression of critical genes involved in carbohydrates and lipid metabolism, such as glucokinase (gck), hexokinase (hk1), and acetyl-CoA carboxylase (acoa1) in the liver, as well as lipase (lpl), cholecystokinin (cck), and trypsin (try1) in the intestine. These results suggest that taurine not only enhances the antioxidant and immune capacity of the fish but also optimizes their energy metabolism and digestion, which could contribute to improved aquaculture diets, promoting more excellent resistance to oxidative stress and better overall health of fish raised under intensive conditions.