低盐对棕点石斑鱼幼鱼渗透压调节、Na^(+)/K^(+)-ATPase活性及相关基因表达的影响  

Effects of low salinity on osmoregulation,Na^(+)/K^(+)-ATPase activity and related gene expression of juvenile Epinephelus fuscoguttatus

作　　者：刘龙龙 罗鸣 陈傅晓 刘金叶 LIU Longlong;LUO Ming;CHEN Fuxiao;LIU Jinye(Key Laboratory of Utilization and Conservation for Tropical Marine Bioresources,Ministry of Education,Hainan Tropical Ocean University,Sanya 572022,China;Hainan Academy of Ocean and Fisheries Sciences,Haikou 571126,China)

机构地区：[1]海南热带海洋学院热带海洋生物资源利用与保护教育部重点实验室,三亚572022 [2]海南省海洋与渔业科学院,海口571126

出　　处：《海洋渔业》2022年第3期315-327,共13页Marine Fisheries

基　　金：国家重点研发计划(2020YFE0200100,2019YFD0900903);热带海洋生物资源利用与保护教育部重点实验室开放课题(UCTMB20204);财政部和农业农村部:国家现代农业产业技术体系(CARS-47-Z18)。

摘　　要：为研究低盐对棕点石斑鱼(Epinephelus fuscoguttatus)幼鱼渗透压调节的影响,将暂养于自然海水(32‰)、体质量为(56.8±3.5)g的棕点石斑鱼幼鱼分别移入不同盐度(6‰、12‰、24‰、32‰)水体中养殖10 d,实验结束时测定血清渗透压、血清Na^(+)、Cl^(-)、K^(+)浓度、鳃Na^(+)/K^(+)-ATPase活性及相关基因表达量、鳃组织学及耗氧率变化。结果表明,血清渗透压及血清Na^(+)、K^(+)浓度随盐度的降低而降低,血清Cl^(-)浓度及肌肉含水量在不同盐度组间无显著性差异(P>0.05)。通过回归分析得到血清等渗点渗透压为343.73 mOsm·kg^(-1),对应盐度为12.59‰。鳃Na^(+)/K^(+)-ATPase活性随盐度的降低呈“U”型变化。在盐度降低时,棕点石斑鱼幼鱼鳃NKAα1基因表达量无显著变化(P>0.05);鳃NKAβ1b基因表达量随盐度降低先降低后升高;鳃NKAα2a基因表达量随盐度降低先升高后降低;鳃NKAα3基因表达量随盐度降低而降低。鳃丝泌氯细胞数量随盐度的降低先降低后增加,鳃小叶泌氯细胞数量在盐度32‰时最多且显著高于盐度6‰、12‰组(P<0.05);各盐度组鳃丝、鳃小叶泌氯细胞长径无显著性差异(P>0.05)。耗氧率随盐度的降低呈上升趋势。综上所述,棕点石斑鱼虽然在10 d内能有效应对6‰~32‰环境盐度的变化,但在盐度6‰时已经受到了低盐胁迫。研究结果可为棕点石斑鱼渗透压调节机制及养殖水体盐度调控提供一定的参考。Brown-marbled grouper Epinephelus fuscoguttatus is a popularly important species in tropical mariculture due to its delicious meat,fast growth and strong disease resistance,and has been widely cultivated in Fujian,Guangdong,Hainan and other places.Salinity is an important environmental factor that affects the growth,development and reproduction of fish.Euryhaline teleosts can maintain the stability of internal environment homeostasis through effective osmotic regulation to adapt to the changes of salinity in their living environment.Epinephelus fuscoguttatus has a wide range of salinity tolerance and has been reported that can live in waters with salinity ranging from 11‰to 41‰,but little is known about its salinity adaptation mechanism.In order to study the effect of low salinity on osmoregulation of juvenile Epinephelus fuscoguttatus,juveniles with an average weight of(56.8±3.5)g temporarily reared in natural seawater(32‰),were transferred into the water with salinity of 6‰,12‰,24‰and 32‰(control group)for 10 d.Serum osmolality,the concentration of Na^(+),Cl^(-),K^(+)in serum,muscle water content,the Na^(+)/K^(+)-ATPase activity and the expressions of NKAα1,NKAβ1b,NKAα2a,NKAα3 in gill were determined,and changes of gill microstructure and oxygen consumption rate were observed at the end of the experiment.Results showed that with the decrease of salinity,serum osmolality of juvenile Epinephelus fuscoguttatus decreased,and the serum osmolality of salinity 6‰group was significantly lower than that of the other groups(P<0.05),while salinity 12‰,24‰,and 32‰groups had no significant differences(P>0.05).The concentrations of Na^(+)and K^(+)in serum decreased with the decrease of salinity,and the concentrations of Na^(+)and K^(+)in salinity 6‰group were significantly lower than that in the control group(P<0.05),while salinity 12‰,24‰,and 32‰groups had no significant differences(P>0.05).There was no significant difference in the concentration of Cl^(-)in serum among the groups(P>0.05).

关 键 词：棕点石斑鱼 盐度 渗透压调节 Na^(+)/K^(+)-ATPase 

分 类 号：S917.4[农业科学—水产科学]