急性温度应激对吉富品系尼罗罗非鱼(Oreochromis niloticus)幼鱼生化指标和肝脏HSP70mRNA表达的影响

THE EFFECT OF ACUTE TEMPERATURE STRESS ON BIOCHEMICAL INDICES AND EXPRESSION OF LIVER HSP70 mRNA IN GIFT NILE TILAPIA JUVENILES(OREOCHROMIS NILOTICUS)

采用温度应激的方法,将尼罗罗非鱼在26℃下驯养3周后,直接放入16℃、21℃、26℃(对照)、31℃和35℃水环境中,在不同温度应激后(0—24h)对鱼体血液和肝脏生化指标及其肝脏HSP70mRNA表达量变化进行了研究。结果表明,各实验组(除对照组外)血清皮质醇水平显著上升(P<0.05)。16℃组血清葡萄糖水平在24h时显著高于其它各组(P<0.05)。血清总蛋白水平与谷丙转氨酶、谷草转氨酶、溶菌酶、碱性磷酸酶活力和肝脏HSP70mRNA表达量在0—24h内基本呈先上升后下降的变化。24h后,16℃组血清甘油三酯含量显著上升,而胆固醇含量显著下降(P<0.05)。16℃和35℃组肝脏丙二醛含量随着应激时间的延长而上升,超氧化物歧化酶和过氧化氢酶活力均呈先上升后下降的变化。温度应激可显著改变罗非鱼的非特异性免疫力、抗氧化能力以及肝脏HSP70mRNA的表达水平。在实际养殖生产中,应密切关注温度的变化,降低温度胁迫对鱼体免疫机能的影响。

Acclimated at 26℃ for 3 weeks, GIFT tilapias （Oreochromis niloticus） were then treated at 16℃, 21℃, 26℃ （control）, 31 ℃ and 35℃ respectively by means of acute temperature stress, and some biochemical indices in serum and liver and expression of HSP70 mRNA were examined over 0--24 h. The results showed that serum cortisol levels for all groups except control group increased significantly over 0--24h （P〈0.05）. Glucose （GLU） level was higher significantly than that of other groups during the period of 24h when fish were transferred to low temperature （16℃） （P〈0.05）. Changes in serum total protein （TP）, glutamic-pyruvic transaminase （ALT）, glutamic-oxaloacetic transaminase （AST）, lysozyme and Alkaline phosphatase （AKP） were increased and then decreased over 0--24h. Serum triglyceride content increased sig- nificantly and cholesterol decreased when fish were transferred to 16℃ （P〈0.05）. Malondialdehyde （MDA） in liver in- creased significantly when fish were transferred to 16℃ and 35℃ over 0--24h, superoxide dismutase （SOD） and catalase （CAT） activities were increased at first and then gradually declined. After temperature stress, expression level of HSP70 mRNA increased significantly, and reached the highest value after 6h and decreased significantly after 24h. Therefore, temperature stress could improve non-specific immunity in serum, anti-oxidative capacity in liver and expression level of HSP70 mRNA. In practice, we should pay close attention to temperature changes in aquaculture production in order to reduce stress on the fish immune function of the temnerature effect.