Study on oxidative stress response and physiological metabolism related indices of Trachinotus ovatus under hyp-oxia stress

We measured the oxidative stress response and physiological metabolism related indices of Trachinotus ovatus under acute and chronic hypoxias stress.Results show that no mortality of fish was found under acute hypoxia stress at water temperature of (23±0.7)℃.The survival rate of fish of body weight of(31.59±3.01)g dropped in consecutive days under chronic hypoxia stress, decreasing to 50% of the initial survival rate on 11^th day.Under the acute hypoxia stress, the catalase (CAT) activity of gill decreased with time, reaching the lowest value at 3^rd hour, then increased and was higher than those in the other groups at 24^th hour significantly (P < 0.05).The contents of malondialdehyde (MDA) and glutathione reductase (GSH), and activity of superoxide dismutase (SOD) increased under hypoxia stress first and then recovered to the normal levels, and the CAT activity in liver decreased significantly than that in the control under chronic hypoxia stress (P < 0.05).The contents of MDA and GSH and activity of SOD all increased significantly (P < 0.05).Under acute hypoxia stress, the liver glycogen (LG) decreased at first and then recovered to the lowest value at 12^th hour, and then recovered to the level of control at 24^th hour.The LG decreased after chronic stress.Under acute hypoxia stress process, the lactate dehydrogenase (LDH) increased at first and then decreased with time, reaching the highest value at 3^rd hour and decreasing to the level of control at 24^th hour.Under chronic hypoxia stress, the LDH was higher than that of the control group significantly (P < 0.05).