盐度胁迫对非洲斑节对虾生理特征的影响

Effects of Salinity Stress on Physiological Characteristics of Penaeus monodon

关键词:  非洲斑节对虾  盐度胁迫  抗氧化能力  渗透  消化能力

Key words:  Penaeus monodon  salinity stress  antioxidant activities  osmoregulation  digestion capacity

摘要:

为探讨不同盐度梯度下非洲斑节对虾（Penaeus monodon）的盐度耐受性，本研究测定了盐度胁迫下对虾生长、渗透、抗氧化及消化指标的变化。实验设置4个盐度梯度（20，30，40，50），以30盐度组作为对照，进行为期35 d的喂养实验。实验结束时计算增重率（Weight Gain Rate，WGR）、特定生长率（Specific Growth Rate，SGR）和成活率（Survival Rate，SR），测定对虾鳃丝总ATPase、Na⁺-K⁺-ATPase活性，血清总抗氧化能力T-AOC、抗氧化物歧化酶SOD、过氧化氢酶CAT、谷胱甘肽过氧化物酶GSH-Px活性及丙二醛MDA含量，以及肝胰腺胃蛋白酶Pepsin、脂肪酶Lipase、淀粉酶Amyase活性。结果显示，盐度胁迫对非洲斑节对虾的生长有抑制作用，存活率随盐度升高而降低；与对照组比较，WGR和SGR在50盐度组最低，呈现显著差异（P<0.05）。盐度胁迫发生时，对虾总ATPase活性升高，随着时间延长，表现出适应状态，实验第35天，各盐度组无显著差异（P>0.05）；而Na⁺-K⁺-ATPase活性在40，50盐度组显著高于对照组（P<0.05）。实验期间SOD变化程度较小，与对照组比较差异不显著（P>0.05）；CAT、T-AOC、GSH-Px活性及MDA含量差异显著（P<0.05），盐度胁迫刺激了非洲斑节对虾抗氧化应激能力。高盐度降低非洲斑节对虾Pepsin、Lipase活性，40，50盐度组尤为显著（P<0.05）；实验第3天，20盐度组显著提升了对虾Amyase活性（P<0.05），降低了Pepsin、Lipase活性（P<0.05）。研究表明，盐度胁迫不利于非洲斑节对虾的生长，但可激活对虾抗氧化能力，使其酶活力得以调节来适应环境的改变，并不同程度地降低对虾的消化能力，从而抑制生长。

Abstract:

In order to explore the salinity tolerance of Penaeus monodoncv under different salinity gradients, the changes in shrimp growth, osmosis, antioxidant and digestive indexes under salinity stress were measured in this study. Four salinity gradients (20, 30, 40, 50) were set in the experiment, and the 30 salinity group was used as a control for a 35 d feeding experiment. At the end of the experiment, Weight Gain Rate (WGR), Specific Growth Rate (SGR) and Survival Rate (SR) were calculated. The activities of ATPase and Na⁺-K⁺-ATPase in the gill, activities of SOD, CAT, T-AOC, GSH-Px and content of MDA in the serum, pepsin, lipase and amylase in the hepatopancreas were measured. The results showed that the growth performance of P. monodon was inhibited under salinity stress, and the survival rate decreased with the increase of salinity. Compared with the control group, WGR and SGR were the lowest in the 50 salinity group, showing significant differences (P<0.05). When the salinity stress occurred, the total ATPase activity of prawns increased, and with the extension of time, it showed an adaptive state. On the 35^th day of the experiment, there was no significant difference between the salinity groups (P>0.05). While the activity of Na⁺-K⁺-ATPase in the 40 and 50 salinity stress groups was significantly higher than the control group (P<0.05). During the experiment, the degree of SOD change was small, and the difference was not significant compared with the control group (P>0.05). The activities of CAT, T-AOC, GSH-Px and the content of MDA were significantly different (P<0.05). Salinity stress stimulated the antioxidant stress ability of P. monodon. High salinity reduced the activities of pepsin and lipase in P. monodon, especially in 40 and 50 salinity stress groups (P<0.05). On the third day of the experiment, the activity of amyase in 20 salinity group was significantly increased (P<0.05), and activities of pepsin and lipase were decreased (P<0.05). The results showed that salinity stress was not conducive to the growth of P. monodon, but it could activate the antioxidant capacity, adjust its enzyme activity to adapt to environmental changes, and the digestibility of the shrimp to varying degrees, thus inhibiting the growth performance.