急性低氧/复氧胁迫对克氏原螯虾抗氧化-能量代谢的影响

为研究低氧/复氧胁迫对克氏原螯虾(Procambarus clarkii)抗氧化及能量代谢的影响,将克氏原螯虾暴露于(1.0±0.1) mg/L急性低氧胁迫和后续(6.8±0.2) mg/L复氧环境中,于低氧胁迫1h、6h及复氧1h、12h分别采集肝胰腺、鳃和血淋巴,研究低氧/复氧胁迫下克氏原螯虾抗氧化-能量代谢酶的活力变化,分析鳃和肝胰腺组织的超微结构改变。在低氧胁迫下,肝胰腺和血淋巴中SOD酶活力显著下降(P<0.05);复氧以后,肝胰腺、血淋巴及鳃组织中SOD酶活力均出现了显著上升(P<0.05)。SOD酶活力变化可能与复氧过程中超氧阴离子自由基的过量产生有关。在复氧12h后,血淋巴和鳃组织中MDA含量均出现了显著性增加(P<0.01),提示机体细胞在复氧胁迫下产生了脂质过氧化。在低氧胁迫下,肝胰腺、鳃和血淋巴中ACP、AKP酶活力显著上升(P<0.05);在复氧12h后,肝胰腺和鳃组织中ACP酶活力显著降低(P<0.01)。显示低氧/复氧胁迫影响了机体的非特异性免疫应答。在急性低氧胁迫下,肝胰腺、血淋巴与鳃组织中的LDH含量和总ATPase活力均显...

ACUTE HYPOXIA/REOXYGENATION STRESS AFFECT ANTIOXIDANT AND ENERGY METABOLISM OF PROCAMBARUS CLARKII

Dissolved oxygen (DO) is vital in aquaculture, which influences the survival and growth of red swamp crayfish, Procambarus clarkii. To reveal the profiles of antioxidant and energy metabolism in response to acute hypoxia/reoxygenation stress, the activity of some key enzymes associated with antioxidant and non-specific immunity were measured and the ultrastructure changes in the hepatopancreas and gill were observed. Experimental crayfish with average body weight of (26.5±1.8) g were subjected to acute hypoxia stress (DO 1.0±0.1 mg/L), followed by reoxygenation (DO 6.8±0.2 mg/L). Hepatopancreas, gill and hemolymph from five groups of crayfish (six crayfish per group), including normoxia, hypoxia for one and six hours, and reoxygenation for one and 12h, were used to measure the changes of antioxidant and non-specific immunity enzymes. Cell ultrastructure of gill and hepatopancreas were also examined by transmission electron microscope. The results showed that the activity of superoxide dismutase (SOD) in hepatopancreas and hemolymph decreased significantly under hypoxia stress (P<0.05), while it increased significantly in hepatopancreas, hemolymph and gill in the reoxygenation stage (P<0.05). The significant increase of SOD activity may be related to the excessive production of superoxide anion (ROS) in the reoxygenation process. The content of malonaldehyde (MDA) in hemolymph and gill tissue was significantly higher than that of the control group (P<0.01), indicating lipid peroxidation occurred in cells under hypoxia/reoxygenation stress. Under hypoxic stress, the activities of acid phosphatase (ACP) and alkaline phosphatase (AKP) in hepatopancreas, gill and hemolymph were both significantly increased (P<0.05), and the activities of ACP in hepatopancreas and gill tissue were significantly decreased after reoxygenation for 12h (P<0.01). These results suggested that hypoxic-reoxygenation stress may affect the immune response of the crayfish. Compared with the control group, lactic dehydrogenase (LDH) content and total ATPase activity in hepatopancreas, hemolymph and gill tissue were significantly increased under acute hypoxic stress (P<0.05), indicating that the energy metabolism function of cells was seriously affected. Observation of mitochondria ultrastructure revealed that the organization structure of gill and hepatopancreas were seriously injured after acute hypoxic/reoxygenation stress. Mitochondrial damage, including mitochondria dissolved into vacuole, mitochondria swelled irregularly and their cristae fractured and become fuzzy. During hypoxia/reoxygenation stress, the number of mitochondria in hepatopancreas cells significantly increased while the number of lysosomes decreased significantly. The results showed that hypoxic-reoxygenation stress can cause great damage to the hepatopancreas and gill of P. clarkii, and affect the activities of antioxidant and non-specific immunity enzymes. Furthermore, the results indicated that hypoxic-reoxygenation stress has great influence on immune defense ability and energy metabolism function of P. clarkii.