本试验旨在比较不同反应温度下日本鳗鲡(Anguilla japonics)及其僵鳗消化酶活性的差异。试验选取正常生长的日本鳗鲡(126.4~140.2 g/尾)以及生长缓慢的僵鳗(3.5~8.6 g/尾)各20尾,取肝胰脏、胃、肠,分别在5、15、25、30、35、40、45和55 ℃反应温度下测定肝胰脏、胃、肠中蛋白酶、淀粉酶、脂肪酶活性。结果表明:正常鳗和僵鳗肝胰脏、胃、肠蛋白酶活性均在45 ℃时达到最高值,且蛋白酶活性(除5、15、55 ℃时的僵鳗蛋白酶活性外)均表现为肠>胃>肝胰脏;僵鳗肝胰脏、肠、胃蛋白酶活性分别为正常鳗的29.5%、15.7%和25.2%(P<0.05)。正常鳗和僵鳗淀粉酶活性均在30 ℃时达到最高值,正常鳗淀粉酶活性(除5 ℃时的淀粉酶活性外)表现为肝胰脏>肠>胃,僵鳗淀粉酶活性表现为肠>肝胰脏>胃;僵鳗肝胰脏、肠、胃淀粉酶活性分别为正常鳗的42.4%、73.7%和43.8%(P<0.05)。正常鳗和僵鳗脂肪酶活性均在35 ℃时达到最高值,正常鳗脂肪酶活性表现为肝胰脏>胃>肠,僵鳗脂肪酶活性(除35 ℃时的脂肪酶活性外)表现为肝胰脏>肠>胃;僵鳗肝胰脏、肠、胃脂肪酶活性分别为正常鳗的41.5%、45.6%和23.2%(P<0.05)。由此可见,日本鳗鲡僵鳗肝胰脏、胃、肠中蛋白酶、淀粉酶及脂肪酶活性均显著低于正常鳗,从而直接影响其生长发育。

This experiment was conducted to study the effects of temperatures on the activities of digestive enzymes in Japanese eels Anguilla japonics (n=20) and growth retarded eels (n=20). The weight of the normal eels was from 126.4 to 140.2 g per eel, and that of growth retarded eels was from 3.5 to 8.6 g per eel. The activities of protease, amylase, and lipase in the normal eels and growth retarded eels under the condition of different temperatures (5, 10, 15, 25, 30, 35, 40, 45 and 55 ℃) were studied. The results showed as follows: with the increasing of temperature, the digestive enzyme activities were increased at first, and then decreased. The optimum temperature of the protease in hepatopancreas, intestine and stomach was 45 ℃. In the same experimental temperature, the order of protease activity was intestine>stomach>hepatopancreas except growth retarded eels at 5, 15 and 55 ℃. The protease activity in hepatopancreas, intestine and stomach of growth retarded eels was only 29.5%, 15.7% and 25.2% of that of the normal eels, respectively (P<0.05). The optimum temperature of amylase activity was 30 ℃, and the order of amylase activity of the normal eels was hepatopancreas>intestine>stomach in experimental temperatures except at 5 ℃, but the order of amylase activity of growth retarded eels was intestine>hepatopancreas>stomach in experimental temperatures. The amylase activity in hepatopancreas, intestine and stomach of growth retarded eels was only 42.4%, 73.7% and 43.8% of that of the normal eels, respectively (P<0.05). The optimum temperature of lipase activity was 35 ℃, and the order of lipase activity of the normal eels was hepatopancreas>stomach>intestine in experimental temperatures, but the order of lipase activity of growth retarded eels was hepatopancreas>intestine>stomach in experimental temperatures except at 35 ℃; the lipase activity in hepatopancreas, intestine and stomach of growth retarded eels was only 41.5%, 45.6% and 23.2% of that of the normal eels, respectively (P<0.05). These results indicate that the activities of protease, amylase and lipase in hepatopancreas, intestine and stomach of growth retarded eels are significantly lower than those of normal eels, which directly affect their growth and development.