盐度对云纹石斑鱼抗氧化酶及溶菌酶活性的影响

为探讨云纹石斑鱼肝脏抗氧化指标和血清溶菌酶活力对盐度骤降的响应,本实验设置4个盐度梯度(27、21、15和9)对云纹石斑鱼进行盐度骤降胁迫实验,在0、1、2、3和7 d时取样,测定其肝脏中超氧化物岐化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH-Px)活力,总抗氧化能力(T-AOC)和丙二醛(MDA)含量,以及血清溶菌酶(LZM)活力。结果显示,SOD与CAT活力第1、2天均呈下降趋势,盐度21组的SOD和CAT活力第3天大幅度升高,显著高于对照组(P0.05),随后第7天下降恢复至正常水平;T-AOC变化趋势与SOD、CAT活力变化一致;MDA含量变化与SOD、CAT活力变化趋势相反;血清溶菌酶活力随盐度降低,呈降低的变化趋势,其中盐度21组第1天为最高值。研究表明:盐度骤降使云纹石斑鱼产生强烈的应激反应,初期抑制SOD和CAT活力,随后恢复,T-AOC和MDA含量也相应变化。溶菌酶活力随时间延长先升高后降低,在非特异性免疫中发挥重要作用。

Effects of salinity on activities of liver antioxidant enzymes and plasma lysozyme of Epinehelus moara

The interactive effects of ambient salinity decrement on liver antioxidant index and plasma lysozyme activity of Epinephelus Moara were investigated by rearing fish at salinity of 27,21,15 and 9 for 7day. We tested activity of superoxide dismutase (SOD),catalase (CAT),glutathione peroxidase (GSH-Px), total antioxidant capacity (T-AOC), malondialdehyde (MDA)content, and plasma lysozyme activity at time periods of 0,1, 2, 3and 7 d respectively.The results showed that the liver SOD as well as CAT activities first droped in 1,2 d (P < 0.05) and peaked in 3 d of group 21, then dropped to normal in 7 d. The T-AOC activity was consistent with the SOD and CAT activities, while the MDA content was contrary. On a whole, plasma lysozyme activity dropped (P < 0.05) with the decrease of salinity and group 21 peaked in 1 d. To sum up, the results indicate that ambient salinity decrement can effectively stimulate and inhibite the SOD and CAT activity in liver of the Epinephelus Moara in initial stage, but it will recover then. T-AOC activity and MDA content will also corresponding change. Plasma lysozyme activity first increased and then dropped with the elapse of treatment time, thus it plays an important role in immune system.