银鲳不同消化器官中消化酶活性的分布及其比较

Distribution and Comparison of Digestive Enzyme Activity of Pampus argenteus in Different Digestive Organs

为了解野生与养殖条件下银鲳不同消化器官中消化酶活性的分布,比较研究了野生银鲳成鱼和养殖银鲳幼鱼的消化酶(蛋白酶、淀粉酶、脂肪酶)活性.结果表明:(1)成鱼胃中蛋白酶活性最大,为0.47U·mg-1,侧囊中蛋白酶活性最小,仅有0.05 U·mg-1;成鱼肝中淀粉酶活性最大,为0.08U·mg-1,直肠最小,为0.01 U·mg-1;肝的脂肪酶活性最大,为10.63 U·mg-1,中肠最小,肝脂肪酶活性约为中肠的9倍.(2)幼鱼三种消化酶活性均为:胃>肝>侧囊,且银鲳幼鱼各消化酶活性总体上高于成鱼,幼鱼胃中蛋白酶活性、淀粉酶活性、脂肪酶活性分别约为成鱼胃的3倍、12倍和1.5倍.(3)银鲳成鱼和幼鱼的A/P值都小于1,且幼鱼各消化器官的A/P值都大于成鱼,A/P值结果表明银鲳为偏肉食性鱼类,野生的成鱼比养殖的幼鱼更适应肉食性.此外,研究还发现银鲳的脂肪酶活性明显高于许多常见海水性鱼类,推断其对脂肪的利用效率较高,可以考虑在银鲳饲料的配制时适当提高饲料中脂肪的比例.

In order to understand the nutritional needs of Pampus argenteus in wild and cultivated conditions, the activity of digestive enzymes（protease, amylase, lipase） of wild adult and cultivated young pomfret in different digestive organs are studied.The results show that：（1） The highest protease activity in stomach is found to be 0.47 U·mg^-1 and the lowest in lateral sac is identified to be 0.05 U·mg^-1 The highest amylase activity in liver is 0.08 U·mg^-1 and the lowest in rectum is 0.01 U·mg^-1 The highest Hepatic lipase activity is 10.63 U·mg^-1 and is about 9 times as large as midgut.（2） Three digestive enzyme activities of juvenile are in the following ascending order： stomach〉 liver 〉lateral sac, and the activity of the digestive enzyme of young pomfret is noted to be generally higher than that of adults. The activities of protease, amylase, lipase of juveniles in stomach are approximately 3 times, 12 times and 1.5 times as large as those of the adults, respectively.（3） The A/P values of adult and juvenile are both less than 1, and the A/P values of digestive organs in juvenile are higher than those of in adults, The A/P results indicate that Pampus argenteus is partially carnivorous fish, and wild adult pomfrets have developed carnivorous adaptation better than farmed young pomfrets. In addition. we also find that the lipase activity of pomfret is significantly higher than that of many common seawater fish, so we conclude that the utilization efficiency of fat is higher in pomfrets, based on which we may consider to increase the fat ratio in the preparation of silver pomfret feed.