不同温度、pH值对鳗鱼消化道蛋白酶和淀粉酶活性的影响

[目的]了解美洲鳗的消化生理特点,为美洲鳗的饲料配制和合理投食提供科学依据。[方法]以30 g左右的健康美洲鳗幼鱼为试验材料,取胃、肠和肝胰脏组织进行匀浆、离心,上清液作为待测酶液,分别测定温度20~60℃和pH值1.0~12.0下,3种消化组织中蛋白酶和淀粉酶活性的变化,研究不同温度、pH值对美洲鳗胃、肠和肝胰脏中蛋白酶和淀粉酶活性的影响以及在不同消化器官中这些消化酶的活性大小变化规律。[结果]美洲鳗胃、肠和肝胰脏蛋白酶的最适温度和最适pH值分别为555、55、0℃和2.0、7.5、7.5,美洲鳗胃、肠和肝胰脏淀粉酶的最适温度均为40℃,最适pH值分别为4.0、7.0、7.0。在反应温度模式下,美洲鳗蛋白酶活性为胃>肠>肝胰脏,淀粉酶活性为肝胰脏>肠>胃。在pH值模式下,蛋白酶活性为肠>胃>肝胰脏,淀粉酶活性为肝胰脏>肠>胃。[结论]美洲鳗胃和肠中蛋白酶活性较高,而淀粉酶活性较低。美洲鳗的A/P值均小于1,说明其为肉食性或偏肉食性。

Effects of Different Temperatures and pH on the Protease and Amylase Activities in the Digestive Tract of Anguilla rostrata

[Objective] The study aimed to know the digestive physiological characteristics of Anguilla rostrata,and provide scientific basis for its feed formulation and reasonably feeding.[Method] With healthy juvenile A.rostrata weighted about 30 g as tested material,the tissues from stomach,intestine and hepatopancreas were made for homogenate and centrifuge.With the obtained supernatants as tested enzyme liquid,the changes of protease and amylase activities in 3 kinds of digestive tissues under the reaction temperature of 20～60 ℃ and pH of 1.0～12.0 were determined resp.The effects of different temperatures and pH on the protease and amylase activities in stomach,intestine and hepatopancreas of A.rostrata and the activities and change law of these digestive enzymes in different digestive organs.[Result] The optimum temperatures and pH were 55,55,50 ℃ and 2.0,7.5,7.5 resp.in turn for protease,the optimum temperatures were all 40 ℃ and the optimum pH were 4.0,7.0,7.0 resp.for amylase in stomach,intestine and hepatopancreas of A.rostrata.Under the mode of reaction temperature,the order of protease activity in different peptic was stomach > intestine > hepatopancreas,the order of amylase activity was hepatopancreas > intestine > stomach.Under model of pH,the order of protease activity was intestine > stomach > hepatopancreas,and that of amylase was hepatopancreas > intestine > stomach.[Conclusion] The protease activity of A.rostrata were higher in stomach and intestine,while the amylase activity were lower.The A/P value of A.rostrata were all less than 1,which indicated that it was carnivorous or partial to be carnivorous.