Effects of waterborne copper on oxidative stress and immune responses in red seabream, Pagrus major

Backgrounds Copper (Cu) plays an essential role in many enzymatic processes including cellular respiration. In this study, we investigated the oxidative stress and immunity of red seabream, Pagrus major , exposed to different concentrations of Cu 2+ (10, 20, 30, and 40 μg/L) for 120 h. Methods We measured the expressions of mRNA, activities of antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT), the levels of plasma hydrogen peroxide (H 2 O 2 ) and lipid peroxide (LPO), and immune parameters lysozyme, immunoglobulin M (IgM), and melatonin. Results The mRNA expressions, activities of antioxidant enzymes, and the levels of plasma H 2 O 2 and LPO were significantly higher after exposure to 30 and 40 μg/L of Cu 2+ than after exposure to lower concentrations (0, 10, and 20 μg/L). However, the levels of plasma lysozyme, IgM, and melatonin were significantly lower after exposure to 30 and 40 μg/L of Cu 2+ . Conclusion These results indicate that Cu 2+ concentrations of 30 and 40 μg/L can induce an acute toxic oxidative stress and decrease the immune response in red seabream in aquarium conditions.