pH对不同日龄的太平洋鳕仔鱼消化酶活力的影响

Effects of pH Values on Digestive Enzyme Activity in Various Day Old Larvae of Pacific Cod Gadus macrocephalus

用酶学分析方法研究了p H对1、16日龄和28日龄的太平洋鳕仔鱼淀粉酶和蛋白酶活力的影响。试验结果表明，在设定的pH范围内，太平洋鳕仔鱼淀粉酶的活力均随pH的升高呈现先升后降的变化趋势。其中，1日龄时淀粉酶最适pH为7．0，16日龄时最适pH为7．0～8．0，28日龄时淀粉酶最适pH为7．5。pH对蛋白酶活力的影响则不同。1日龄时，蛋白酶最适pH为8．0，而到16日龄和28日龄，最适pH降至2．6～3．0。可以看出，随着发育过程中器官和组织的完善，淀粉酶的最适pH偏碱性，而蛋白酶的最适pH则由碱性变为酸性，说明对蛋白消化有主导作用的酶的种类在逐渐发生转变。

Effects of pH values on activities of amylase and protease were studied in 1 ,16 ,and 28 day old larvae of Pacific cod Gadus macrocephalus by means of enzyme analyses .The activities of amylase were found increase in the larvae first and then decrease with pH increasing within the designed pH ranges ,with the optimal pH of 7 .0 for 1 day old larvae ,7 .0~8 .0 for 16 day old ones and 7 .5 for 28 day old ones .The specific activities of protease were shown to have different effects ,with the optimum pH of 8 .0 for 1 day old larvae ,2 .6~3 .0 for 16 day old ones and 2 .6~3 .0 for 28 day old ones .With the organogenesis and development of tissues ,the optimal pH of amylase was found in weak alkaline ,while the optimal pH of protease was changed from alkalinity to acidity .