溶解氧水平对花鲈幼鱼氧化应激与能量利用的影响及生理机制

Effects of Dissolved Oxygen Levels on Oxidative Stress Response and Energy Utilization of Juvenile Chinese Sea Bass(Lateolabrax maculatus)and Associate Physiological Mechanisms

为研究低氧胁迫对花鲈(Lateolabrax maculatus)幼鱼血液生理生化、氧化应激和能量利用的影响。本试验将花鲈幼鱼放置于低溶解氧水平下((1.56±0.24)mg/L)胁迫3、6、12和24h,然后在正常溶氧水平下((7.72±0.18)mg/L)恢复3和12h,分别测定了血细胞、血清代谢物以及不同组织中抗氧化酶与能量供应物质。研究表明:低氧胁迫能够使花鲈幼鱼的白细胞数目(WBC)、红细胞数目(RBC)、血红蛋白含量(HGB)和血小板数目(PLT)显著上升(P<0.05),恢复正常溶氧后与对照组无差异;血清中谷丙转氨酶(ALT)、谷草转氨酶(AST)、乳酸脱氢酶(LDH)和甘油三脂(TG)的变化与血细胞变化规律较一致,碱性磷酸酶(ALP)、总蛋白(TP)、白蛋白(ALB)和总胆固醇(TC)含量先显著下降(P<0.05)后逐渐上升到正常水平。肝脏中超氧化物歧化酶(SOD)和谷胱甘肽-S-转移酶(GST)呈先增加后减少的趋势,且GST变化在肝组织中较敏感,可作为花鲈在应对氧化应激时的酶学指标;而肝脏中糖原和乳酸含量则在低氧处理后显著降低(P<0.05)。鳃组织中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽-S-转移酶(GST)和丙二醛(MDA)均出现不同程度的升高。肌组织中SOD和CAT活力在低氧处理后显著降低(P<0.05),MDA含量和糖原含量则显著升高(P<0.05)。研究结果显示,低氧胁迫能够对花鲈幼鱼机体造成显著的氧化损伤,使血液生化指标、不同组织的相关酶活力及能量供应发生显著变化,而在恢复正常溶氧水平后又可通过自身生理调节逐渐恢复到正常水平。

In order to study the effect of hypoxia on the hematological physiology,oxidative stress response and energy utilization of Chinese sea bass(Lateolabrax maculatus),the fish were treated at dissolved oxygen content of((1.52±0.24)mg/L)for 3 h,6 h,12 h and 24 h and then recovered at the normal((7.72±0.18)mg/L)for 3 h and 12 h with the blood cells,serum metabolites and the levels of antioxidant enzymes and energy supply substances in different tissues determined,respectively.Hypoxia increased the blood cell count(WBC),red blood cell count(RBC),platelet count(PLT)and hemoglobin content(HGB)significantly(P<0.05)and decreased to the normal level after recovery at normal dissolved oxygen content.Glutamate pyruvic transaminase(ALT),aspartate transaminase(AST),lactate dehydrogenase(LDH)and triglyceride(TG)were consistent with the change of blood cells.Alkaline phosphatase(ALP),total protein(TP),albumin(ALB)and total cholesterol(TC)significantly decreased(P<0.05)and then returned to the normal.The activity of superoxide dismutase(SOD)and glutathione-S-transferase(GST)in liver increased first and then decreased.The change of GST in liver tissue is more sensitive to hypoxia,which can be used as an enzyme indicator of L.maculatus suffering the oxidative stress.The contents of glycogen and lactic acid in liver significantly decreased after hypoxia treatment(P<0.05).The activities of SOD,GST,catalase(CAT)and malondialdehyde(MDA)in gill increased differentially.The activity of SOD and CAT in muscle significantly decreased(P<0.05)while the contents of MDA and glycogen in muscle significantly increased(P<0.05).The results of this study showed that hypoxia stress can cause significant oxidative injury to juvenile L.maculatus and change the blood biochemical indexes,the activities of related enzymes in different tissues and energy supply.After being recovered to normal dissolved oxygen,the changed parameters can gradually return to the normal through the physiological regulation of fish.