急性盐度胁迫对克氏双锯鱼幼鱼血清皮质醇浓度和Na^＋-K^＋-ATP酶活性的影响

Effect of acute salinity stress on serum cortisol and activity of Na^+-K^+-ATPase of juvinile Amphiprion clarkii

研究了克氏双锯鱼(Amphiprion clarkii)幼鱼由盐度35突变至30、25、20和15后血清皮质醇浓度及鳃丝和肝脏中Na+-K+-ATP酶活性的变化。结果表明,盐度变化对克氏双锯鱼的存活无影响,而对其血清皮质醇浓度及Na+-K+-ATP酶活性均有显著影响(P<0.05)。各低盐胁迫组血清皮质醇浓度均在处理的24 h内呈先降后升趋势,处理后第48、第96小时,各处理组血清皮质醇浓度急剧降低至对照组水平甚至略低于对照组,与对照组无显著差异(P>0.05);鳃丝和肝脏中Na+-K+-ATP酶活性变化规律一致,即低盐胁迫24 h内呈上升趋势,第48及第96小时变化趋势与血清皮质醇浓度变化相似。整体上,以上各生理指标变化幅度均与盐度的降低幅度呈正相关。实验结果证明,盐度突变对克氏双锯鱼幼鱼的血清皮质醇浓度及Na+-K+-ATP酶活性存在重要的影响,同时也表明该鱼具有较强的盐度适应能力。

We studied the changes in serum cortisol and Na＋-K＋-ATPase activities in gill and liver of juvenile Amphiprion clarkii at an abrupt change in salinity from 35 （control） to 15 at decrement of 5. The results show that salinity changes had no significant effects on survival but affected serum cortisol and Na＋-K＋-ATPase activities of the juveniles significantly （P 〈 0.05 ）. The concentration of serum cortisol showed a downward trend after the juveniles were abruptly transferred to low salinities in 24 h, then all decreased to the control level at 48th hour and even lower than control level at 96th hour, showing no significant difference. The trends of Na＋-K＋-ATP ase activ- ity in gill and in liver were highly consistent. The Na＋-K＋-ATPase activities in the two tissues increased obviously in 24 h, then sharp- ly declined in the same way as serum cortisol level at 48th hour and 96th hour （ P 〉 0. 05）. In summary, the variation amplitude of these physiological indices mentioned above showed a positive correlation to the salinity decreased degree. Therefore, there is a signifi- cant impact of salinity changes on the concentration of serum cortisol and Na＋-K＋-ATPase activity of A. clarkii. It is revealed that A. clarkii has strong salinity adaptability.