菊黄东方鲀仔稚鱼生长及其消化酶与抗氧化酶活性

Growth,digestive enzyme and antioxidant enzyme activities of tawny puffer(Takifugu flavidus)larvae.

对2～30日龄菊黄东方纯（Takifuguflavidus）鱼苗的全长与体质量、主要消化酶和2种抗氧化酶活性进行测定，研究菊黄东方纯仔稚鱼的生长特点以及消化能力与抗氧化能力的变化．结果表明：菊黄东方鲍仔稚鱼全长与日龄呈线性相关，体质量与日龄呈指数相关；全长与体质量呈幂函数增长相关，且为异速生长．在菊黄东方纯仔稚鱼中未检测到脂肪酶活性，胰蛋白酶与胃蛋白酶活性存在“互补性”变化；在2～6日龄期间，胰蛋白酶活性快速降低至最低值，胃蛋白酶活性则显著升高（P〈0．05）至最大值，10日龄后，胰蛋白酶活性开始增强，最大值出现在19日龄，胃蛋白酶活性保持稳定．淀粉酶活性在2和19日龄最大，至15日龄降至最低．碱性磷酸酶活性在2日龄最低，15日龄达到最大．2～10日龄，超氧化物歧化酶（superoxidedismutase，SOD）和过氧化氢酶（catalase，CAT）活性的变化趋势相似，均在6日龄最大；10日龄后SOD活性逐渐增强，CAT活性呈“波浪形”变化．研究表明，菊黄东方纯开口摄食前体内就已存在相应的消化酶和抗氧化酶，其活性与菊黄东方鲍发育阶段密切相关，亦在不同程度上受到外界环境和食性等因素的影响．

Summary It is well documented that, due to the changing nutritional requirements and shifting from endogenous to exogenous feeding, fishes experience evolutionary adaptations in the morphogenesis of their digestive system during early developmental stages. This fact is also reflected in the ontogeny of digestive enzyme patterns. To maintain health and prevent oxidation-induced lesions and mortalities, there must be effective antioxidant systems operating in fish larvae. The components of these systems involve antioxidant compounds and antioxidant enzymes. It is well known and generally acknowledged that many biological and physiological systems are poorly developed in fish larvae. Therefore, a comprehensive analysis of the ontogenic changes occurring during the early life stages of fish is essential for the design of adequate larval rearing and feeding strategies and also for the formulation of dry diets. The overall aims of this study were to understand the characterization of the growth, digestive enzyme andantioxidant enzyme activities in tawny puffer （Takifugu flavidus） during the early development in order to enhance the growth and quality of early life stages by avoiding nutrient and oxidation problems that may cause pathologies and diseases. Total length, body mass, main digestive enzymes and antioxidant enzymes of tawny puffer larvae from 2 to 30 day-old were determined. The relationship between total length or body mass and day-old could be fixed to the linear and exponential functions, respectively. 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. Lipase activity was not detected in tawny puffer larvae. The activities of trypsin and pepsin followed a complementary variation pattern. Trypsin activity showed a rapid decrease from 2 to 6 day-old, and reached to the minimum level （109.17 U/rag） at 6 day-old. Meanwhile, pepsin activity increased significantly （P〈0.05） and reached to the maximum level （1.09 U/mg） at 6 day-old. Amylase activity reached to the maximum （about 0.30 U/mg） at 2 and 19 day-old respectively, followed by the minimum （0. 11 U/mg） at 15 day-old. Alkaline phosphatase had minimum activity （82.01 U/g） at 2 day-old, followed by the maximum （249.55 U/g） at 15 day- old. The activities of superoxide dismutase （SOD） and catalase （CAT） showed a similar variation tendency. Both the maximum levels （SOD： 30.99 U/mg, CAT： 646.36 U/g） appeared at 6 day-old. The SOD activity increased gradually from 10 day-old, while the CAT activity showed a wavy change. In conclusion, kinds of digestive and antioxidant enzymes have existed in the body of tawny puffer larvae before the preparation of their food intake, and the activities are closely related to the developmental stage and also are affected by external environment and feeding habit in different degrees.