盐度胁迫对杂交鲟生理及存活的影响

Effect of Salinity Stress on Physiological Status and Survival in Hybrid Sturgeon

为探究不同盐度胁迫下,杂交鲟(达氏鳇♀×施氏鲟♂)幼鱼的生理状态和存活情况,分别在0、5、10、15和20这5种盐度条件下分析了胁迫后1、6、12、24、48、96 h杂交鲟的血清非特异性免疫相关指标、肝脏抗氧化酶和鳃钠/钾—三磷酸腺苷酶活力。试验结果表明,盐度10、15、20试验组的杂交鲟分别在96、12、1 h内全部死亡,盐度5试验组及对照组杂交鲟没有死亡。盐度5试验组在盐度胁迫后,鳃部钠/钾—三磷酸腺苷酶活力迅速升高,血清总蛋白浓度在12 h达到峰值,碱性磷酸酶活力缓慢上升(P>0.05),溶菌酶活力除48 h达峰值(P<0.05)外,其余与对照组无明显差异。盐度10试验组溶菌酶活力在胁迫后6 h显著上升,碱性磷酸酶活力在胁迫24 h时达到峰值,之后在48 h急剧下降(P<0.05),谷丙转氨酶活力除12 h外,均显著高于对照组及盐度5试验组。盐度15试验组在胁迫后6 h溶菌酶活力显著升高,血清总蛋白浓度急剧下降。各试验组的肝脏超氧化物歧化酶活力和丙二醛含量均呈先升后降再缓慢升高的趋势,在胁迫12 h达到最低值,盐度10试验组变化幅度大于盐度5试验组;各试验组的肝脏过氧化氢酶活力在胁迫1 h降至最低值(P<0.05),而后升高,在12 h时达到峰值,再降低。

To investigate the effects of abrupt salinity changes on survival rates and physiological status,hybrid sturgeon（ Siberian huso sturgeon Huso dauricus ♀ × Amur sturgeon Acipenser schrenckii ♂） juveniles with body weight of（ 7. 28 ± 0. 56） g were transferred to freshwater（ control） and salinity levels of 5,10,15,and 20. The serum non-specific immune indicators,activities of antioxidant enzymes in liver and activities of Na＋/ K＋-ATPase in gill were analyzed 1,6,12,24,48,and 96 h after salinity change. The results showed the fish exposed to a salinity of 20 were all found dead within one hour,exposed to salinity of 10,and 15 all dead in 96 h and 12 h,respectively,while no mortality occurred in salinity 5 group and control groups. Activities of gill Na＋/ K＋-ATPase in salinity 5 group increased sharply after immergence,the serum total protein level were at peak at 12 h,and serum acid phosphatase（ AKP） activity increased slightly（ P〉0.05）. While there were no significant differences between salinity 5 and control groups except for peak at 48 h（ P〈0.05）. In salinity 10 group,the activities of serum lysozyme significantly rose at 6 h,and AKP activity reached a maximum at 24 h after that decreased dramatically（ P〈0.05）. Obviously,the activities of serum alanine aminotransferase（ ALT） in salinity 10 group were significantly higher than those in salinity 5 or control groups except the activity at 12 h. In salinity 15 group,activities of serum lysozyme significantly rose at 6h（ P〈0.05）,at the same time,the serum total protein declined rapidly. The activities of superoxide dismutase（ SOD） and contents of malonaldehyde（ MDA） in liver in all groups showed the same trend as firstly increasing,then decreasing,after that slightly rising,and the minimum at 12. Also,the range of changes in salinity 10 group was greater than in salinity 5 group. Activities of liver catalase（ CAT） in each group were decreased to the minimum at 1 h（ P〈0.05）,then elevated to the maximum at 12 h,and decreased continuously.