低盐度和不同硫酸铜浓度对银鲳鳃离子调节酶和肝抗氧化功能的影响

开展银鲳(Pampus argenteus)试养海域的盐度易随气候降低, 且受到一定程度Cu等重金属污染, 研究低盐条件下硫酸铜对银鲳的影响十分必要。本实验首先进行银鲳幼鱼低盐度适应, 将盐度以4的幅度从24逐步降低至12。稳定后进行硫酸铜胁迫, 在盐度12下CuSO₄·5H₂O浓度梯度设为0、0.1、0.3、0.5 mg·L^–1, 盐度24下CuSO₄·5H₂O浓度梯度设为0、0.5 mg·L^–1, 胁迫持续144 h。通过检测两种鳃离子调节酶: Na⁺/K⁺-ATP酶(NKA)和V-H⁺-ATP酶(VHA), 以及3种肝抗氧化活性物质－还原型谷胱甘肽(GSH)、超氧化物歧化酶(SOD)和过氧化氢酶(CAT), 探究低盐条件下铜离子对银鲳幼鱼上述指标的影响。结果显示, 盐度逐步降低后, NKA与VHA活力呈上升后下降的变化, 之后NKA活力随硫酸铜浓度增加而减弱; VHA活力加入硫酸铜后都出现显著下降, 其中CuSO₄·5H₂O 0.3 mg·L^–1与0.5 mg·L^–1组在72 h时下降更为明显; 盐度24硫酸铜组NKA和VHA活力都在24 h时增强而后减弱。GSH含量和SOD活力在盐度降低时出现跃升, CAT活力则呈波动变化, 加入硫酸铜后, 0.3 mg·L^–1与0.5 mg·L^–1组GSH含量持续下降后显著上升而后回落; 各硫酸铜组SOD活力都出现增强后回落的变化; 0.3 mg·L^–1与0.5 mg·L^–1组CAT活力在72 h有显著增强。本实验表明, 铜离子对NKA与VHA有抑制作用, 盐度降低时其作用更强; GSH、SOD和CAT的变化能反映低盐度和铜离子对银鲳的伤害程度。银鲳对水体铜离子有一定的抗性, 但在盐度降低等环境变化时, 应当密切注意水体中铜等重金属浓度。

The effects of low salinity and different CuSO4 concentrations on gill ion-regulatory enzyme activities and liver antioxidant function in silver pomfret

The salinity will fall depending on the climate in the experimental aquaculture areas of ). And these ares were polluted to a certain extent by some heavy metal such as copper. Therefore, it is necessary to investigate the effect of different CuSO₄ concentrations on silver pomfret in low salinity sea. This study investigated the effects of low salinity on juvenile silver pomfret firstly. We decreased salinity from 24 to 12 by three steps, the salinity change of every step was 4. When fish was in a stable condition, they concentrations was set to in salinity 12, or 0, 0.5 mg in salinity 24. The copper expose was sustained for 144h. Then two kinds of ion-regulatory enzyme activities in gill: Na⁺/K⁺-ATPase (NKA) and V-H⁺-ATPase (VHA) activities, three kinds of antioxidants in liver: glutathione (GSH) contents, superoxide dismutase (SOD) and catalase (CAT) activities of silver pomfret were tested in order to reveal the the effect of water copper on those index of silver pomfret in low salinity sea. In this study, NKA and VHA activities rose then decreased during the salinity decline. After CuSO₄ added into water4 concentration. VHA activities decreased significantly after CuSO₄ added, especially group at salinity 24 increased at 24th hour and then decreased. GSH contents and SOD activity increased significantly through the salinity decline. Meanwhile, CAT activity fluctuated. After CuSO₄ added into water· groups decreased firstly, then increased significantly at 72 h. SOD activities of each CuSO₄ group increased firstly then returned. CAT activities of 0.3 and 0.5 mg increased significantly at 72 h. This study suggested that water copper affected silver pomfret with inhibition of NKA and VHA, especially, in low salinity. The change of GSH, SOD and CAT can reflect the damage of low salinity and CuSO₄ on silver pomfret. The resistibility of silver pomfret to water copper is between a certain range, but we should pay attention to the concentrations of heavy metal such as copper in water when the water environment has changed, for example, salinity had fallen.