盐度对大麻哈鱼幼鱼肝脏组织学、非特异性免疫酶及消化酶活力的影响

Salinity and Juvenile Chum Salmon(Oncorhynchus keta):Effects on Liver Histomorphology,Non-specific Immune and Digestive Enzymes

为研究盐度对大麻哈鱼幼鱼非特异性免疫酶、消化酶活力及肝脏组织结构的影响,试验设置4个盐度组(0‰、8‰、16‰、24‰),周期42天,取肝脏和消化道分别测定非特异性免疫酶和消化酶活力,并观察肝脏组织结构变化。结果表明:大麻哈鱼幼鱼肝脏超氧化物歧化酶、谷胱甘肽过氧化物酶和过氧化氢酶活力变化趋势一致,随着盐度升高均呈现出先上升后下降的趋势,但其活力峰值不同;碱性磷酸酶活力随盐度升高呈现先升后降的趋势,而盐度对各组之间酸性磷酸酶活力无显著影响(P>0.05);盐度对消化道各种消化酶活力影响复杂且各种消化酶之间并未表现出整体效应;组织切片显示盐度0‰、8‰、16‰组肝脏结构正常,而盐度24‰组则呈现一定程度病变。推测体重1 g左右的大麻哈鱼降海洄游时比较适宜的盐度范围介于8‰~16‰之间。

The paper aims to study the effects of various salinities on liver histomorphology, non-specific immune and digestive enzymes activities in juvenile Chum salmon(Oncorhynchus keta). The Chum salmon was cultured in salinities 0‰, 8‰, 16‰ and 24‰ for 42 days,respectively, we measured the non-specific immune enzyme and digestive enzyme activities by using the liver and digestive tract, and observed the liver structure change under different salinities. The results showed that: the trend of superoxide dismutase,glutathione peroxidase and catalase activities in the liver of juvenile Chum salmon increased first and then decreased with the increase of salinity, but the enzyme activity peaks were different;the alkaline phosphatase activity increased first and then decreased with the increase of salinity, but different salinity treatment groups had no significant effects on acid phosphatase activity(P>0.05);different salinities had complicated effects on various digestive enzymes’ activities in the digestive tract and there was no overall effect between various digestive enzymes;histological observation showed that the liver structure of the salinity group 0‰, 8‰, and16‰ was normal, while the salinity group 24‰ showed a certain degree of lesions. It is speculated that 8‰-16‰ is the optimal salinity for juvenile Chum salmon with the body weight about 1 g during the catadromous migration period.