温度与盐度对吉富品系尼罗罗非鱼幼鱼生长和肝脏抗氧化酶活力的协同影响

Synergistic effects of water temperature and salinity on the growth and liver antioxidant enzyme activities of juvenile GIFT Oreochromis niloticus

采用中心复合试验设计(CCD)和响应曲面方法(response surface methodology,RSM),探讨了温度(16～37℃)和盐度(0～18)对吉富罗非鱼幼鱼生长和肝脏抗氧化酶活力的协同影响.结果表明:温度和盐度的一次与二次效应对吉富罗非鱼幼鱼特定生长率(SGR)有显著影响(P<0.05),随着温度或盐度的上升,其特定生长率呈先升后降的变化.温度与盐度间存在互作效应(P<0.05),温度为16～20℃时,幼鱼的特定生长率在盐度为9～10时较高;在温度27～32℃、盐度3～5时较高;高温环境下(35～37℃),淡水环境中的幼鱼生长较快.温度和盐度分别为28～30℃和6～8时,超氧化物歧化酶(SOD)和过氧化氢酶(CAT)的活力较高,温度的一次效应与盐度的二次效应对两种酶活力均有显著影响(P<0.05),温度与盐度对CAT活力有互作效应,高温与高盐环境会抑制SOD和CAT活力的表达.SGR、SOD和CAT因子与响应值间二次多项回归方程的决定系数分别达到0.954、0.831和0.942(P<0.05),可用于预测;温度效应对吉富罗非鱼幼鱼生长和抗氧化酶活力的影响较盐度明显.在罗非鱼的养殖过程中应合理安排养殖环境,降低氧化胁迫,以促进罗非鱼的生长与抗病力的提高.

By adopting two-factor central composite design （CCD） and response surface methodology （RSM）, this paper studied the synergistic effects of water temperature （16-37 ℃） and salinity （0-18） on the specific growth rate （SGR） and liver superoxide dismutase （SOD） and catalase （CAT） activities of juvenile GIFT Oreochromis niloticus. Water temperature and salinity had significant linear and quadratic effects on the SGR （P0.05）, respectively. With increasing water temperature or salinity, the SGR decreased after an initial increase. There existed significant synergistic effects between water temperature and salinity （P0.05）. The SGR was higher at 16-20 ℃ and salinity 9-10, at 27-32 ℃ and salinity 3-5, and at 35-37 ℃ and in freshwater. The SOD and CAT activities were higher at 28-30 ℃ and salinity 6-8. The linear of temperature and quadratic of salinity had significant effects on the two enzymes （P0.05）, and there was a significant synergistic effect on CAT activity. High temperature and high salinity were not favorable to the expression of SOD and CAT activities. The coefficients of determination of quadratic regression equations for SGR, SOD and CAT activities reached to 0.954, 0.831, and 0.942 （P0.05）, respectively, and could be used for prediction. The growth and antioxidant enzyme activities were more affected by water temperature than by water salinity. In the culture practice of O. niloticus, it would be necessary to optimize culture environment and reduce oxidative stress to promote the growth and disease- resistance of the tilapia.