日本黄姑鱼早期发育过程中消化酶活性变化研究

Assessment of digestive enzymes activities during the early development of Nibea japonica

测定了日本黄姑鱼(Nibea japonica)早期发育过程中的多种消化酶活性。结果表明,在日本黄姑鱼的胚胎发育阶段即能检测出较低的淀粉酶、脂肪酶和碱性磷酸酶活性,而胃蛋白酶和酸性磷酸酶不能被检出;淀粉酶、脂肪酶和胃蛋白酶的活性随着仔稚鱼的生长变化显著,淀粉酶和脂肪酶在仔鱼孵化后活力迅速增强,在仔鱼开口前比活值增至较高水平,分别为(0.433±0.010)U/mg和(388.53±16.16)U/g,这表明日本黄姑鱼在开口前体内就已经存在相应的消化酶,并可能具备了一定的碳水化合物和脂类的消化能力,为其食物摄取作准备。胃蛋白酶活性最早于8d仔鱼中检出,比活力值仅为(0.33±0.09)U/mg,之后15d内仔稚鱼酶活力快速增强,23d稚鱼胃蛋白酶比活力显著高于其余各组,为(1.83±0.12)U/mg。在受精卵内能检测出微弱的碱性磷酸酶活力,且在仔鱼孵化后酶比活力缓慢上升,至13d仔鱼,酶比活力值达到峰值,为(156.74±5.17)U/g,之后值稳定于较高水平,标志着仔稚鱼阶段日本黄姑鱼肠道消化功能逐渐完善,可能是仔鱼主要消化场所。

Kinds of digestive enzymes activities were studied in Nibea japonica of the early development stage.The results showed： amylase,lipase and alkaline phosphatase activities can be detectable during embryonic development stage,while pepsin and acid phosphatase could not be detected.Activities of amylase,lipase and pepsin changed significantly with the growth of fish larvae,amylase and lipase activity in the larvae increased rapidly after hatching,and reached the higher level before first-feeding stage,mounted respectively（0.433 ± 0.010） U/mg and（388.53 ± 16.16） U/g.It showed that kinds of digestive enzymes had existed in the body of Nibea japonica for the preparation of their food intake,which could help the digestion of carbohydrates and lipids.The activities of pepsin were earliest detectable in the 8d larvae,specific activity was valued at only（0.33 ± 0.09） U / mg.The activities rapidly increased during the later 15 days,and reached the highest value in the 23 day larvae,amount（1.83±0.12）U/mg.The weak alkaline phosphatase activity which could detected in the fertilized eggs increased slowly after hatching,and it reach the peak value（156.74 ± 5.17） U / g in the 13 day larvae,afterward the values stabilized at a higher level,which indicated that intestine was the main digestive place,and its digestive function had been perfected gradually during the development of Nibea japonica larvae.