Synergistic Effects of Dietary Vitamin C and Selenium on Induced Methylmercury Toxicity in Juvenile Olive Flounder Paralichthys olivaceus

The synergistic effects of dietary vitamin C and selenium (Se) on induced methylmercury (MeHg) toxicity in juvenile olive flounder Paralichthys olivaceus were examined in this study. Nine diets containing 3 different vitamin C levels (0, 200 and 400 mg kg diet in the form of L-ascorbyl-2-monophosphate), 3 different Se levels (0, 2 and 4 mg kg diet in the form of selenomethionine) at a constant level of MeHg (20 mg kg diet in the form of MeHg) were formulated and fed to triplicate groups of juvenile olive flounder with mean weight of 2.00±0.04 g (mean± SD) in semi recirculation system using 3 factorial design. Growth performance and tissue Hg burden were determined after 8 weeks of feeding. Fish fed diets containing 400 mg kg vitamin C together with 2 and 4 mg kg Se (C400Se2 and C400Se4) showed significantly (P<0.05) higher weight gain (WG), specific growth rate (SGR) and feed efficiency (FE). Whereas fish which were under the C400Se4 diet exhibited significantly (P<0.05) higher and protein efficiency ratio (PER) than other feeding groups. Tissue Hg burden in muscle, liver and kidney showed a tendency of increasing with decreasing the levels of vitamin C and Se. However, significantly low tissue Hg burden was observed from fish fed diets containing 400 mg kg vitamin C together with 2 and 4 mg kg Se (C400Se2 and C400Se4). The results suggested that tissue Hg burden could be reduced and MeHg mediated growth problems could be ameliorated by supplementing dietary vitamin C and Se in juvenile olive flounder.