不同蛋白含量饲料对南方鲇胃蛋白酶和淀粉酶活性的影响

为探讨营养、饲料与鱼类消化酶之间的相互作用，采用蛋白含量分别为44．8％、29．1％和13．3％的饲料饲养南方鲇(Silurus meridionalis)，并在第0d、15d、25d和50d对胰脏、胃黏膜、前肠黏膜和后肠黏膜的胃蛋白酶(酸性蛋白酶)和淀粉酶活性进行了动态分析。结果显示：1)饲料中蛋白含量为29．1％—44．8％时南方鲇的生长速度显快于低蛋白含量饲料(13．3％)；2)在实验后期(25d后)，中等蛋白含量饲料组南方鲇的生长速度比其他两组快，此阶段该组鱼胃黏膜的胃蛋白酶活性呈上升趋势，而另两组该酶活性则呈下降趋势；低蛋白饲料组前肠黏膜和后肠黏膜的淀粉酶活性在实验后期急剧下降，与该组鱼的生长最慢相关联；3)在实验的50d内，不同蛋白含量饲料对胃蛋白酶和淀粉酶活性在各组织器官中的分布特征影响不大。实验期间，南方鲇消化器官中这两种消化酶活性的变化情况表明，在实验的不同阶段，饲料中的蛋白含量对南方鲇胃蛋白酶和淀粉酶的合成、分泌和活性大小的影响是不同的。

EFFECT OF DIFFERENT DIETARY PROTEIN CONTENT ON ACTIVITIES OF PEPSINAND AMYLASE OF SILURUS MERIDIONALIS CHEN

In order to research the relationship between the nutrients or feedstuffs and the digestive enzymes in fish,it was studied in this paper that the changes of pepsin or acid protease and amylase activities in pancreas,stomach,foregut and hindgut of Silurus meridionalis were measured at 0d,15d,25d and 50d with different protein content diet,containing protein 44.8%,29.1%and 13.3%and naming high protein content diet(HPCD),intermediate protem content diet(IPCD)and low protein content diet (LPCD) respectively.The results are as follows: 1) Silurus meridionalis in HPCG and IPCD groups (44.8% and 29.1%) grow faster than does in LPCD group;In the anaphase (after 25d),the growth rate of this fish in IPCD group is biggest.It shows that the protein content in pellets is about 29.1% or little more,but not more than 45%. 2) During the former experiment (before 25d),the pepsin or acid protease activities in stomach show the tendency to decrease in all three groups.But in the later experiment(after 25d),the pepsin activity in stomach of S.meridionalis in the IPCD group tends to increase,while that to decrease in other two groups.These show that the protein content in diets can influence the pepsin activities in stomach of the fish.The acid protease activities in pancreas,foregut and hindgut are very low,they had very little action on digesting diet.Combined to the growth of this fish,it shows that there have some correlations between the changes of pepsin activities in stomach and growth after a period time of rearing. 3) In the whole experiment,the amylase activities in pancreas are higher than that in other three organs or tissues in the three groups.And in the earlier experiment(before 15d),the amylase activities in pancreas decreased slowly,but increased rapidly from 15d to 25d.Then this enzyme activity became stable after 25d in the HPCD group,but in other two groups the activities kept to increase. 4) During the whole the amylase activities fluctuated to some extent in all groups,but in the later period(after 25d),the amylase activities in the foregut and hindgut in the LPCD group decrease rapidly,but this enzyme activities still increase in the same time.These also suggest that amylase enzyme activities or their changes correlate to the growth of this species. 5) Over the whole experiment,the characters of the distribution of pepsin or acid protease and amylase activities to all tissues or organs studied are similar in all three groups. It shows that the protein content in diets did not influence the distribution of these two enzyme activities to all tissues or organs. The changes of the two enzyme activities among the three groups in the experiment suggest that how much protein in diets influences the synthesis,secretion and action of pepsin in stomach and amylase of this species.