溶解氧水平对褐牙鲆幼鱼能量代谢和氧化应激的影响研究

【目的】查明溶解氧含量下降对褐牙鲆(Paralichthys olivaceus)幼鱼能量代谢及氧化应激的影响。【方法】测定褐牙鲆幼鱼在溶解氧由7.4mg/L下降至0.9mg/L过程中耗氧率、排氨率、氧氮比以及氧化应激指标的变化。【结果】随着溶解氧含量(DO)降低,褐牙鲆幼鱼耗氧率呈"U"型变化,氧氮比呈倒"U"型变化,褐牙鲆幼鱼肌肉中丙二醛(MDA)含量增加,尽管肌肉和肝脏中过氧化物歧化酶(SOD)酶活性有增强的趋势,但由于体内产生过多的活性氧自由基,使得脂质过氧化反应增强,脂质过氧化物增多,机体仍表现出氧化损伤。【结论】褐牙鲆幼鱼的能量代谢指标和部分氧化应激指标对溶解氧含量下降有明显反应,可作为判断溶解氧含量是否对褐牙鲆产生胁迫及调控养殖水体溶解氧含量的依据。

Study on the Energy Metabolism and Oxidative Stress of Juvenile Brown Flounder,Paralichthys olivaceus in Dissolved Oxygen Content Descending Water

Objective] To investigate the effects of descending dissolved oxygen content on the energy metabolism and oxidative stress in brown flounder, Paralichthys olivaceus.Methods] The experiment determined the dynamics of oxygen consumption rate, ammonia-N excretion rate, atomic number ratio between oxygen consumption and ammonia-N excretion (O:N),and parameters of oxidative stress of juvenile brown flounder in the water with the dissolved oxygen content (DO) descending from 7.4 mg/L to 0.9 mg/L.Results] As DO descending, the oxygen consumption presented an "U" type fluctuation,an upside-down "U" type fluctuation of O:N appeared, and the malonaldehyde content (MDA) in the muscle increased. It was found that the activity of SOD in muscle and liver increased as DO descend. Inspire of this, higher metabolism rate in low DO water may produced superabundant active oxygen radicals and thus enhanced appearance of lipid peroxidation. As a result, lipid peroxidation may be accumulated and causes oxidative damage.Conclusion] Energy metabolism and partial oxidative stress parameters of juvenile flounder were significantly affected by descending of dissolved oxygen content. So these parameters can be used as indexes for the appearance of low dissolved oxygen content stress and control of the dissolved oxygen content in cultural water.