Effects of acute high salinity stress on survival,gill tissue and hepatic antioxidant capacity of juvenile Thamnaconus septentrionalis
To investigate the adaptive ability and physiological and biochemical regulation of Thamnaconus septentrionalis under high salinity stress,and to compare the survival,gill tissue structure,Na+/K+-ATPase activity,and hepatic antioxidant capacity of juveniles in different salinity groups,salinity treatment groups were set up,and juveniles subjected to 96 h of high-salinity stress were studied.The study can provide basic data and theoretical basis for the production of artificial seawater aquaculture of Thamnaconus septentrionalis and the selection and breeding of salt-tolerant strains.There was no mortality of juvenile Thamnaconus septentrionalis in salinity group 35;juvenile mortality began to occur in salinity groups 40,45 and 50 at 24 h of stress;at 96 h,the mortality rates of salinity groups 40,45 and 50 were 10％,13.33％and 100％,respectively,and the mortality rates of salinity groups 45 and 50 were significantly higher than that of salinity group 40(P＜0.05).The LC50 of juvenile Thamnaconus septentrionalis were 47.062,46.279,45.886,and 45.736 at 24,48,72,96 h,respectively,which showed a decreasing trend in LC50 with the increase of stress time.Changes in gill filament structure were not obvious in the salinity 35 group compared with the control group.In salinity group 40,the secondary lamellas were bent,the epithelial cells were severely edematous,the cytoplasm was hyaline and more ruptured,the cells appeared to be vacuolated,the number of mitochondria-rich cells of gill filaments as a whole increased,the bases of the secondary lamellas were enlarged obviously,and the fusion phenomenon appeared in the neighboring secondary lamellas.In salinity group 45,secondary lamellas were significantly shortened,secondary lamellas flat epithelial cells were severely ruptured and detached,the outline was blurred,cell vacuolization increased,mitochondria-rich cells filled the secondary lamellas,and the fusion of secondary lamellas increased gradually with the prolongation of the stress time.Except for the content of MDA,Na+/K+-ATPase activity and hepatic antioxidant capacity of the three treatment groups were significantly higher than that of the control at all time points(P＜0.05),and most reached the peak at 48 h,then decreased at 72 h.The results showed that high salinity stress had a significant effect on the survival,gill tissue structure,Na+/K+-ATPase activity,and liver antioxidant capacity of juvenile Thamnaconus septentrionalis.The larvae of Thamnaconus septentrionalis have some self-regulation ability under high salinity stress,but excessive salinity will cause damage to the larval organism and reduce the resistance of the larvae,which will ultimately lead to the death of the larvae.The normal growth salinity of juvenile Thamnaconus septentrionalis can be up to 35,and salinities above 40 will significantly affect the survival and growth of juveniles.
万方数据
维普
