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| Effect of Salinity Stress on Physiological Status and Survival in Hybrid Sturgeon |
| WANG Xiaowen,ZHU Hua,KUANG Xinyu,HU Hongxia |
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Abstract To investigate the effects of abrupt salinity changes on survival rates and physiological status , hybrid sturgeon (Siberian huso sturgeon H uso dauricus♀ × Amur sturgeon A cipenser schrenckii ♂) ju‐veniles with body weight of(7 .28 ± 0 .56) g were transferred to freshwater (control) and salinity levels of 5 ,10 ,15 ,and 20 .The serum non‐specific immune indicators ,activities of antioxidant enzymes in liver and activities of Na+ /K+‐ATPase in gill were analyzed 1 ,6 ,12 ,24 ,48 ,and 96h after salinity change . The results showed the fish exposed to a salinity of 20 were all found dead within one hour ,exposed to sa‐linity of 10 ,and 15 all dead in 96h and 12 h ,respectively ,w hile no mortality occurred in salinity 5 group and control groups .Activities of gill Na+ /K+‐ATPase in salinity 5 group increased sharply after immer‐gence ,the serum total protein level were at peak at 12h ,and serum acid phosphatase (AKP) activity in‐creased slightly(P> 0 .05) .While there were no significant differences between salinity 5 and control groups except for peak at 48 h(P<0 .05) .In salinity 10 group ,the activities of serum lysozyme signifi‐cantly rose at 6 h ,and AKP activity reached a maximum at 24h after that decreased dramatically ( P<0.05) .Obviously ,the activities of serum alanine aminotransferase (ALT)in salinity 10 group were signif‐icantly higher than those in salinity 5 or control groups except the activity at 12 h .In salinity 15 group ,ac‐tivities of serum lysozyme significantly rose at 6h(P<0 .05) ,at the same time ,the serum total protein de‐clined rapidly .The activities of superoxide dismutase (SOD) and contents of malonaldehyde (MDA) in liv‐er in all groups showed the same trend as firstly increasing ,then decreasing ,after that slightly rising ,and the minimum at 12 .Also ,the range of changes in salinity 10 group was greater than in salinity 5 group . Activities of liver catalase(CAT)in each group were decreased to the minimum at 1 h(P<0 .05) ,then ele‐vated to the maximum at 12h ,and decreased continuously .
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Received: 25 October 2015
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