Effects of dietary vitamin C on growth, antioxidant enzyme activity and immune‐related gene expression of Pampus argenteus.

As a micronutrient, vitamin C plays an important role in growth and immunity of fish, but the effects of vitamin C on Pampus argenteus were still unclear. Here, we added vitamin C with different concentrations (0, 350, 1050, 2100 and 4200 mg/kg) to the basic diet, and the optimal concentration of vitamin C was screened out as 1050 mg/kg through the growth indicators, antioxidant enzyme activities (SOD, CAT, GSH‐PX and MDA) and the expression of four immune‐related genes (IL‐2, IL‐3, IL‐17 and IL‐18). After feeding dietary vitamin C supplementation with optimal concentration for 4 weeks, 80 ml/t formaldehyde was used to damage the immune system of fish. Then, the activities of the antioxidant enzymes and immune‐related genes were tested to find out the protective effects of vitamin C on the immune system. The results showed that the activity of CAT, SOD and GSH‐PX increased, while the MDA content decreased. At the molecular level, the expression of IL‐2 and IL‐3 genes increased, but the expression of IL‐17 and IL‐18 genes was inhibited. These findings suggested that the dietary vitamin C supplementation improved fish growth, alleviated the stress reaction caused by formaldehyde treatment and improved the immunity of P. argenteus. [ABSTRACT FROM AUTHOR]