太平洋鳕仔鱼期消化酶活性的变化

Development of Digestive Enzymes in Gadus macrocephalus Larvae

用酶学分析法研究太平洋鳕仔鱼发育过程中胰蛋白酶、酸性蛋白酶、淀粉酶和脂肪酶活性的变化。结果表明:4种酶的比活力均在初孵时即可检出,但比活力变化趋势不同;胰蛋白酶比活力在仔鱼孵化初期较高,随后显著降低;酸性蛋白酶比活力在早期仔鱼阶段比较低,且较为稳定,从14日龄开始显著升高;淀粉酶比活力在3日龄即达到最大值,之后显著降低,并一直保持较低的比活力;脂肪酶的比活力一直较低,在5日龄达到最大值,之后比活力大幅度下降。仔鱼发育过程中,各种酶活性变化显著(p<0.05),太平洋鳕在仔鱼期已经可以消化蛋白质、脂肪和碳水化合物。

The development of digestive enzymes was examined in laboratory-reared larvae of Gadus macrocephalus from 0 to 30 days after hatch （DAH）. The trypsin, acid protease, amylase and lipase activities of the larvae were investigated. The total activities of these digestive enzymes were detected, and showed a gradual increase from 0 to 30 DAH, but the activities of these enzymes present different trends. The specific activities of trypsin showed the maximum on 4 DAH followed by a quick decline and then stayed at low level from 5 to 30 DAH. The enzyme activities of acid protease stayed at low and stable level from 0 to 12 DAH and began to significantly increase from 14 DAH. The specific activities of amylase showed the maximum on 3 DAH, and followed by a quick decline and stayed at low level. The specific activities of lipase showed the similar trend as amylase. The maximum of lipase appeared on 5 DAH. Significant variations （p 〈 0.05） in specific activities of all the enzymes were found. The composition of digestive enzymes indicates that the larvae of Gadus macrocephalus are able to digest protein, lipid and carbohydrates at an early stage.