半滑舌鳎仔稚鱼消化酶活性的变化

对半滑舌鳎不同发育阶段主要消化酶（酸性蛋白酶、碱性蛋白酶、淀粉酶、脂肪酶）以及与消化吸收相关的碱性磷酸酶的活性变化进行了测定。结果表明，半滑舌鳎在仔鱼发育早期即可检出酸性蛋白酶和碱性蛋白酶的活力，碱性蛋白酶的2个极低值分别出现在仔鱼开口期和仔稚鱼的转交期，从孵化后23d左右胃腺出现时，酸性蛋白酶的活性开始明显升高。早期仔鱼体内表现出较强的淀粉酶活性，孵化后12d其活性急剧下降，并一直保持较低的比活力状态。脂肪酶的活性在半滑舌鳎早期仔鱼体内一直较低，进入稚鱼期后开始缓慢上升。碱性磷酸酶活性在变态结束后出现大幅度的升高，这标志着肠组织结构和肠道消化功能的完善。

Variations in Digestive Enzymes Activities in Tongue Fish Cynoglossus semilaevis Larvae and Juveniles

The varitions in activities of main digestive enzymes (acid protease,alkaline protease,amylase and lipase) and alkaline phasphatase in different development stages of tongue fish Cynoglossus semilaevis were determined.It is shown from the determined results that the activities of acid protease and alkaline protease in tongue fish can be detected in the early larval development stage,two extreme low alkaline protease activities were observed during the period of the first feeding and the transition from larva to juve-(nile),and the activity of acid protease increased obviously from the appearance of gastric gland(about the 23rd day after hatch).The noticeable amylase activity was exhibited in the early larval stage,the activity decreased drastically from the twelfth day after hatch,and then kept at a low specific activity level.The lipase activity kept at a low level in the early larval stage and then increased slowly after entering the juve-(nile) stage.After the metamorphosis was completed,the alkaline phosphatase activity increased rapidly,which indicates the maturity of enterocytes and the improvement of digestive mechanism of intestines.