泥鳅仔稚鱼发育期间消化酶及碱性磷酸酶比活力的变化

研究了泥鳅(Misgurnus anguillicaudatus)从孵化至30 DAH(日龄,Days after hatching)几种消化酶及碱性磷酸酶比活力的变化情况。胃蛋白酶直至30 DAH仍未检出活性。而胰蛋白酶表现出较高的比活力,其比活力在初次摄食之后显著上升,6 DAH达到最大值之后开始显著降低(P<0.05)。脂肪酶与淀粉酶的变化模式相似,在内源性营养向外源性营养转变及仔鱼向稚鱼转变这两个时间段出现两个高峰值。碱性磷酸酶比活力在2-6 DAH显著上升(P<0.05),之后开始下降并趋于平稳。研究表明,泥鳅在仔稚鱼阶段只具有结构性的胃而缺乏分泌细胞的分化。2-6 DAH是泥鳅仔鱼肠道功能迅速发育的阶段,也是向成鱼消化模式转变的一个重要过程。脂肪酶和淀粉酶比活力的持续性表明了泥鳅仔鱼对糖类和脂肪有较好的利用能力。

Changes of digestive enzymes and alkaline phosphatase specific activities in Misgurnus anguillicaudatus during the development of early larval ontogeny

The specific activities of several digestive enzymes(pensin,trypsin,lipase,amylase) and alkaline phosphatase of Misgurnus anguillicaudatus were determined from hatching to 30 DAH(days after hatching).Pepsin activity could not be detected during the entire period of the experiment.In contrast,trypsin performed a high level activity after hatching,and its specific activity increased significantly after first feeding,peaking at 6 DAH,and decreased abruptly after that.The variation of lipase and amylase shared a similar pattern,their specific activities had two obvious peaks around the time of the transition of endogenous to exdogenous feeding and the beginning of the transportation of larval stage to juvenile stage.From 2 to 6 DAH,the specific activity of alkaline phosphatase significantly increased and then declined to a roughly stable level.This study demonstrated that M.anguillicaudatus has only a structural not functional stomach during the larval stage.The period of 2 to 6 DAH was the stage of the maturation of digestive gut in M.anguillicaudatus larvae and the crucial step forward the digestion mode of adult M.anguillicaudatus.The steadiness of these specific activities suggested that M.anguillicaudatus was efficient to utilize carbohydrate and lipid in food.