盐度骤变对金钱鱼幼鱼抗氧化状态的影响

Effects of abrupt salinity changes on antioxidant statusof juvenile Scatophagus argus

为研究盐度骤变对金钱鱼(Scatophagus argus)幼鱼抗氧化状态的影响,以体质量为(6.27±0.28)g的金钱鱼幼鱼为研究对象,设置1个对照组盐度20,2个盐度骤变组5和35,在盐度骤变0 h、6 h、12 h、24 h、48 h、96 h、7 d时,分别测定幼鱼肝脏、鳃和肌肉组织中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、还原型谷胱甘肽(GSH)和丙二醛(MDA)4种抗氧化指标。结果显示:各盐度组7 d内金钱鱼幼鱼存活率为100%。肝脏中SOD和CAT活力随盐度处理时间的延长先下降后上升;7 d时,盐度5组中4种抗氧化指标均恢复至对照组水平,但盐度35组中SOD和CAT活力显著高于对照组(P<0.05)。鳃中4种抗氧化指标在盐度5和35组中的变化总趋势均为先升高后降低,7 d时多恢复至对照组水平。肌肉中SOD活力盐度5和35组均先升高后降低至对照组水平;CAT活力在盐度5组中波动平缓,而在盐度35组中先降低后升高至对照组水平;肌肉中GSH和MDA含量在各时间点和各盐度组间均无显著差异(P>0.05)。研究表明,金钱鱼幼鱼对于盐度骤变适应性较强,适合驯养。与盐度骤升相比,金钱鱼幼鱼在盐度骤降时产生的氧化压力较小,恢复时间较快。研究结果为金钱鱼幼鱼养殖过程中的盐度驯化提供了一定指导。

In order to realize the effects of acute salinity stress on antioxidant system of juvenile Scatophagus argus,juveniles with body weight of(6.27±0.28)g were taken as research objects,a control group with salinity of 20 and two groups with sudden changes of salinity of 5 and 35 were set up.Four kinds of antioxidant indexes of superoxide dismutase(SOD),catalase(CAT),glutathione(GSH)and malondialdehyde(MDA)in liver,gill and muscle of juveniles were determined at 0 h,6 h,12 h,24 h,48 h,96 h and 7 d after salinity treatment.Results showed that the survival rate of juveniles was 100%within 7 d in all salinity groups..The activity of SOD and CAT in the liver firstly decreased and then increased with the prolongation of salinity treatment time.On 7 d,four antioxidant indexes in the salinity 5 group all restored to the level of the control group,but the activity of SOD and CAT in salinity 35 group were significantly higher than those of the control group(P<0.05).The general trend of changes of four antioxidant indexes in the gills of salinity 5 and 35 groups was that they increased first and then decreased,and most of them restored to the level of the control group on 7 d.In salinity 5 and 35 groups,the SOD activity in muscle increased firstly and then decreased to the level of the control group.CAT activity fluctuated gently in salinity 5 group,but decreased first in salinity 35 group and then increased to the level of the control group.There was no significant difference in the content of GSH and MDA in muscle among different time points and different salinity groups(P>0.05).Results showed that juvenile Scatophagus argus had strong adaptability to sudden changes in salinity and were suitable for salinity acclimation.Compared with the sudden increase in salinity,juvenile Scatophagus argus produced less oxidative stress and the recovery time was shorter when the salinity dropped sharply.This study provides some guidance for salinity acclimation in the process of juvenile Scatophagus argus culture.