温度和盐度对吉富品系尼罗罗非鱼幼鱼鳃Na+-K+-ATPase活力的联合效应

试验采用中心组合设计(central composite face-centered design,CCF)和响应曲面法(response surface methodology,RSM)研究了温度(12—34℃)和盐度(0—26)两因素对体长为(4.36±0.105)cm,体重为(2.45±0.153)g的吉富品系尼罗罗非鱼(GIFT Nile tilapia,Oreochromis niloticus;简称吉富罗非鱼)幼鱼鳃Na+-K+-ATPase活力的联合效应。结果表明:(1)温度和盐度的一次效应和二次效应对Na+-K+-ATPase活力影响极显著(P<0.01),温度和盐度的互作效应不显著(P>0.05);(2)经响应曲面法分析,随着温度和盐度的增大,Na+-K+-ATPase活力呈先减小后增大的趋势;(3)建立了Na+-K+-ATPase活力与温度、盐度间关系的模型方程(R2=0.9829,Pred.R2=0.8550,P<0.01),并可用于预测吉富罗非鱼幼鱼鳃Na+-K+-ATPase的活力;(4)优化结果显示,温度为24.15℃,盐度为11.75时,Na+-K+-ATPase活力最小为0.62μmol无机磷.mg-1蛋白.h-1,满意度函数值高达0.961。Na+-K+-ATPase活力可以作为检测罗非鱼生长性能的指标,其活力较低时,一般反映了鱼体生存环境适宜,生长代谢旺盛,消耗于渗透调节的能量较少。

Combined effect of temperature and salinity on the Na+-K+-ATPase activity from the gill of GIFT tilapia juveniles(Oreochromis niloticus)

Central composite face-centered design(CCF) and response surface methodology were used in the experiment to examine the combined effect of temperature(12—34℃) and salinity(0—26) on the Na+-K+-ATPase activity from the gill of tilapia juveniles(GIFT strain)(mean body length(4.3±0.105)cm and mean body weight(2.45±0.153)g).The results showed that:(1)The linear and quadratic effects of temperature and salinity on the Na+-K+-ATPase activity were highly significant(P<0.01),and the interactive effect between temperature and salinity was nonsignificant(P>0.05);(2)Using the response surface method,the Na+-K+-ATPase activity varied with increasing temperature and salinity in a curvilinear way;(3)The model equation of the enzyme activity towards temperature and salinity was established,with R2=0.9829 and Pred.R2=0.855(P<0.01).The model equation could be practically used for forecasting the gill Na+-K+-ATPase activity in GIFT Nile tilapia juveniles;(4)Via applying statistical optimization of the response of interest,results showed that the optimal factor combination was 24.15℃/11.75,at which the minimum Na+-K+-ATPase activity,0.62μmolPi·mg-1pr·h-1,was reached,with the desirability as high as 0.961.The Na+-K+-ATPase activity can be used as an indicator of growth of GIFT Nile tilapia juveniles.In general,It can be said that the environment in which the Na+-K+-ATPase activity is weaker is suitable for the tilapia juvenile growth,and in this case the metabolism of tilapia is more efficient,and the energy consumed for osmoregulation is smaller.