盐度变化对多鳞四指马(鱼友)幼鱼鳃丝Na^+/K^+-ATP酶及肝脏抗氧化酶活性的影响

Effects of salinity on activities of gill Na^+/K^+-ATPase and liver antioxidase in juvenile Eleutheronema rhadinum

设30、24、18、12、6和淡水6个盐度梯度,对平均体重5.19±0.48 g的多鳞四指马(鱼友)(Eleutheronema rhadinum)幼鱼进行7 d、28 d和56 d的饲养,测定了不同盐度对多鳞四指马(鱼友)幼鱼鳃丝Na+/K+-ATP酶及肝脏超氧化物岐化酶(SOD)、过氧化氢酶(CAT)活性及丙二醛(MDA)含量的影响。结果显示:在盐度30、24组饲养7 d、28 d和56 d,同一盐度组鳃丝Na+/K+-ATP酶活性无显著性差异(P>0.05);饲养7d后,随盐度的降低鳃丝Na+/K+-ATP酶活性显著升高(P<0.05);盐度18、12和6组中Na+/K+-ATP酶活性28 d后趋于稳定,与56 d差异不显著(P>0.05);淡水组中,鳃丝Na+/K+-ATP酶活性28 d后趋于稳定,但显著高于其它盐度组(P<0.05)。肝脏抗氧化酶结果显示:盐度30和24组各时间段CAT活性均无显著性差异(P>0.05);盐度18、12、6组,随着盐度降低,7 d时SOD和CAT活性显著升高(P<0.05),28 d后下降并趋于稳定;28 d与56 d无显著性差异(P>0.05)。淡水组中SOD和CAT活性随时间的延长均表现出持续升高的趋势(P<0.05)。盐度30和24组,同一盐度不同时间MDA含量无显著性差异(P>0.05);除淡水组外,同一时间下MDA含量均随盐度降低而降低,且各盐度组7 d时MDA含量最高,28 d后下降并趋于稳定。多鳞四指马(鱼友)幼鱼对低盐的耐受力较强,盐度0～30均能养殖。

Effects of salinity on the activities of gill Na ~/K ~ -ATPase and liver superoxide dismutase （ SOD）, catalase （CAT） and malondialdehyde （MDA） of liver in juvenile Eleutheronema rhadinum were studied. Six levels of salinities were set ： salinity 30, 24, 18,12,6 and freshwater, and juveniles with the average weight of 5.19 ＋ 0.48 g were raised for 7 d, 28 d and 56 d in the experiment. Results showed that the activity of gill Na ~/K ~ -ATPase in salinity 30, 24 group had no significant difference for 7 days,28 days and 56 days （P 〉 0.05）. With the decrease of salinity, the activities of gill Na ~/K ~ -ATPase increased significantly after 7 days （P〈0.05）, but declined and stabilized after 28 days in salinity 18,12 and 6 group, showing no significant difference with those of 56-day group （ P 〉 0.05 ）. In freshwater, the activities of gill Na ~/K ~ - ATPase also stabilized after 28 days （ P 〉 0.05 ）, but higher than those of other salinity groups significantly （P 〈 0.05）. Results of liver antioxidase showed that, at salinity 30 and 24, the activities of CAT had no significant difference among three periods （P 〉 0.05 ）. With the decrease of salinity, the activities of SOD and CAT increased significantly on the 7th day in salinity 18, 12 and 6 group（ P 〈 0.05 ）, and declined to stabilize after 28 days, showing no significant difference with those of 56 days （ P 〉 0.05 ）. The activities of SOD and CAT showed the tendency of continuing rise with increasing time in freshwater （ P 〈 0.05 ）. There was no significant difference in the content of MDA in salinity 30,24 group in different periods （ P 〉 0.05 ）. The content of MDA decreased with decreasing salinity except in freshwater, and the content of MDA on the 7th day was the highest among three periods in all salinity groups, then declined to stabilize after 28 days（P 〉 0.05 ）. The results showed that juvenile Eleutheronema rhadinum could endure low salinity, and could be bred in salinity 0 -30.