梭鱼早期发育过程中生长及主要消化酶活性的研究

选取梭鱼(Liza haematocheila)受精卵及出膜后3~28日龄鱼苗为研究对象,研究了主要消化酶活性的变化以及鱼苗的生长特点。结果表明,梭鱼苗全长、体重与日龄均呈指数相关;全长与体重呈幂函数增长相关,且为异速生长。梭鱼受精卵及鱼苗可检测到胰蛋白酶、胃蛋白酶、淀粉酶、碱性磷酸酶和酸性磷酸酶活性,且在受精卵中活性较低,未检测到脂肪酶活性。3~16日龄,胃蛋白酶活性逐渐降低至最小值,胰蛋白酶活性先升高,最大值出现在10日龄,之后降低,16日龄后,两种酶活性均显著升高(P0.05),均在28日龄达到最大;淀粉酶活性分别在3~10日龄和22~28日龄不断升高,最大值出现在28日龄;3~7日龄,碱性磷酸酶和酸性磷酸酶均显著升高(P0.05),7~22日龄碱性磷酸酶不断降低,酸性磷酸酶保持稳定,22~28日龄,两种磷酸酶活性均显著升高(P0.05),碱性磷酸酶和酸性磷酸酶活性的最大值分别在7日龄和28日龄。研究表明,梭鱼仔鱼消化酶并非外源性饵料所致,其活性与梭鱼发育阶段密切相关,亦在不同程度上受到外界环境和食性等因素的影响。

Studies on growth and digestive enzyme activities during the early development of Liza haematocheila

In this study, fertilized eggs and 3-28 day-old larvae of Liza haematocheila were selected as the research objects. The growth characteristics and changing trends of main digestive enzymes were researched. The relationship between total length or body mass and day old could be fixed to the exponential functions. The general correlation equation of total length and body mass was power function under artificial farming conditions, and the growth (in mass) in relation to total length was allometric. The activities of trypsin, pepsin, amylase, alkaline phosphatase and acid phosphatase could be detected in all test samples, while lipase activity could not be detected. Enzymes (except pepsin) activities were the lowest in fertilized eggs. Pepsin activity showed a rapid decrease from 3 to 16 day-old, and reached to the minimum level at 16day-old. Meanwhile, trypsin activity increased significantly at first, and reached the maximum level at 10 day-old, then bagan to decrease. Both pepsin and trypsin activities increased significantly from 16 day-old (P<0.05), and reached the maximum levels at 28 day-old. Amylase activity increased from 3 to 10 day-old and 22 to 28 day-old, respectively, and reached the maximum at 28 day-old. Both alkaline phosphatase and acid phosphatase activities increased significantly from 3 to 7 day-old (P<0.05). Alkaline phosphatase activity decreased from 7 to 22 day-old, while acid phosphatase activity remained stable. Alkaline phosphatase and acid phosphatase activities reached the maximum levels at 7 and 8 day-old, respectively. In conclusion, digestive enzymes were not caused by exogenous bait, and the activities were closely related to development stage and also were affected by external environment and feeding habit in different degrees.