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Synergistic effects of dietary vitamin E and selenomethionine on growth performance and tissue methylmercury accumulation on mercury‐induced toxicity in juvenile olive flounder, Paralichthys olivaceus (Temminck et Schlegel)

Moniruzzaman, Mohammad, Park, Gunhyun, Yun, Hyeonho, Lee, Seunghan, Park, Youngjin, Bai, Sungchul C
Aquaculture research 2017 v.48 no.2 pp. 570-580
Paralichthys olivaceus, acetates, alpha-tocopherol, antioxidants, bioaccumulation, dose response, experimental diets, feed conversion, flounder, growth performance, juveniles, kidneys, liver, mercury, methylmercury compounds, muscles, protein efficiency ratio, selenium, selenomethionine, specific growth rate, synergism, toxicity, weight gain
An 8‐week feeding trial was conducted to evaluate the synergistic effects of dietary vitamin E and selenomethionine (SeMet) on induced methylmercury (MeHg) toxicity in juvenile olive flounder Paralichthys olivaceus. Nine semi‐purified diets were formulated to contain three different vitamin E levels as DL‐α‐tocopheryl acetate (0, 100 and 200 mg TAkg⁻¹ diet) and three different selenium (Se) levels (0, 2 and 4 SeMet mg kg⁻¹ diet) on the constant mercury toxicity level (20 mg MeHgkg⁻¹ diet). Nine experimental diets, in a 3² factorial design (E₀Se₀, E₀Se₂, E₀Se₄, E₁₀₀Se₀, E₁₀₀Se₂, E₁₀₀Se₄, E₂₀₀Se₀, E₂₀₀Se₂ and E₂₀₀Se₄), were fed to triplicate groups of fish averaging 2.3 ± 0.04 g (mean ± SD) in the semi‐recirculation system. After 8 weeks of feeding trial, vitamin E and Se showed significant effects on weight gain (WG) of fish (P < 0.05). We found that there was a clear trend of increasing WG with elevating vitamin E and Se levels in the diets. Feed efficiency (FE), specific growth rate (SGR), protein efficiency ratio (PER) and survivability exhibited a similar trend with WG. Both antioxidants had significant interaction effects on FE and PER (P < 0.05). Methylmercury concentrations in fish muscle, liver and kidney decreases in a dose‐dependent manner as dietary vitamin E and Se levels increase. Interestingly, the most significant interactive effects of vitamin E and Se were found in liver tissue for depleting Hg concentrations (P < 0.05). These findings suggest that dietary vitamin E more than 100 mg TA kg⁻¹ diet with 2 or 4 mg SeMet kg⁻¹‐supplemented diets could have synergistic effects on growth and liver mercury bioaccumulation on MeHg‐induced toxicity in juvenile olive flounder.