卵形鲳鲹消化酶活性的研究ⅢpH对幼鱼和成鱼消化酶活性的影响

研究了pH对卵形鲳鲹幼鱼和成鱼3种主要消化酶(蛋白酶、淀粉酶和脂肪酶)活力的影响。实验用鱼暂养7 d后解剖取样,在设计的10个酶反应pH值(2.2,3.2,4.2,5.2,6.2,7.2,8.0,8.6,9.6,10.6)下测定消化酶活力。结果表明:卵形鲳鲹胃内pH为强酸性,幼鱼肠内为中性偏酸性,肝、幽门盲囊和成鱼肠内为中性偏弱碱性。胃蛋白酶的最适pH值幼鱼为2.2,成鱼为3.2;肝、幽门盲囊和肠的蛋白酶活性最适pH值幼鱼为7.2,成鱼为8.0。淀粉酶活性的最适pH值幼鱼为8.0,成鱼为8.6。脂肪酶活性的最适pH值均为弱酸性,幼鱼和成鱼均为6.2。卵形鲳鲹幼鱼和成鱼3种相同消化酶活性的变化趋势相似,并以胃蛋白酶、肠淀粉酶、肠脂肪酶的活力最高。

On digestive enzyme activity of Trachinotus ovatus Ⅲ Effects of pH on activity in young and adult fish

Effects of pH on 3 major digestive enzyme activity(protease,amylase and lipase) in young and adult Trachinotus ovatus were studied.The fish were acclimated in lab for 7 days,and then dissected for enzyme activity measurement under 10 different reactive pH values(2.2,3.2,4.2,5.2,6.2,7.2,8.0,8.6,9.6,and 10.6).Results indicated that strong acid condition was found in stomach,neutral and acidic in intestines of young fish and neutral and weak alkaline in other organs.The optimum pH of protease in stomach was 2.2 in young fish,and 3.2 in adult fish.The optimum pH of protease in liver,pyloric caecum and intestine were 7.2 in young fish and 8.0 in adult.The optimum pH for amylase activity was found to be 8.0 in young fish and 8.6 in adult.The optimum pH of lipase was 6.2 in both young and adult fish.In conclusion,similar change trend of digestive enzyme activity were found in both young and adult fish,with the peak values in stomach protease,intestine amylase and intestine lipase activity.