Effects of vitamin A on growth, serum anti-bacterial activity and transaminase activities in the juvenile Japanese flounder, Paralichthys olivaceus

Abstract The present study examined the effects of dietary vitamin A (vitA) deficiency and excess on growth, serum anti-bacterial activity and serum enzyme activities of juvenile Japanese flounder, Paralichthys olivaceus . Three semi-purified diets containing 0, 10,000 and 25,000 International Units of vitA per kg of diet (IU vitA/kg) were fed to juvenile Japanese flounder (initial weight 1.59 g) for 120 days. At the end of the feeding trial, blood samples were taken from the fish for haematocrit, serum biochemical analysis and serum anti-bacterial activity. Growth performance, in terms of weight gain and specific growth rate, was improved significantly ( P