盐度对绿鳍马面鲀存活、抗氧化酶及组织结构的影响OA北大核心CSTPCD

The greenfin horse-faced filefish(Thamnaconus septentrionalis),an emerging species for cage aquaculture along the coast of China,undergoes significant salinity fluctuations during the rainy season in summer.Therefore,understanding the impact of salinity on the survival and physiological indicators of T.septentrionalis is of great significance for the development of cage aquaculture.In this study,the 96 h semilethal salinity of T.septentrionalis was determined.Subsequently,the low-salinity(15)and high-salinity(40)groups were established.Dynamic changes in physiological indicators after salinity stress at different time points were analyzed,and the changes in the tissue structure of the liver,gills,and kidneys were recorded.The results indicated that the 96-h semilethal salinity was 10.74 for the low-salinity group and 42.95 for the high-salinity group.The Na+-K+-ATPase activity in the gills of both the low-and high-salinity groups indicated an increasing trend,which was significantly higher than that in the control group at 96 h(P<0.05).The activities of superoxide dismutase and catalase in the liver of both the low-and high-salinity groups revealed an initial increase followed by a decreasing trend,and at 96 h,the activities were lower in these groups than in the control group.The activity of glutathione peroxidase in the low-salinity group showed a decreasing trend,followed by an increase,and,at 96 h,it was significantly lower than that in the high-salinity group(P<0.05).Malondialdehyde content in the liver of the low-and high-salinity groups reached a maximum at 96 h,which was significantly higher than that in the control group(P<0.05).The tissue sections revealed that hepatocytes in the low-and high-salinity groups exhibited vacuolation and nuclear condensation,with more severe effects in the high-salinity group.The gill epithelial cells displayed a disorderly arrangement and cell necrosis,with widened filaments and elongated lamellae in the low-salinity group,whereas the high-salinity group exhibited filament shrinkage and increased lamellar spacing.In the kidney tissues,the low-salinity group showed dilation of the renal tubules and enlargement of the renal sacs,whereas the high-salinity group exhibited necrosis of the renal tubules and glomeruli.The findings on the effects of salinity on survival,antioxidant enzymes,and tissue structure in this study provide theoretical support for the healthy aquaculture of T.septentrionalis.