低氧胁迫对日本沼虾呼吸代谢和抗氧化能力的影响

为阐明低氧胁迫对日本沼虾呼吸代谢和氧化代谢的影响,并初步探讨其作用机制及日本沼虾的抗氧化响应机制,将日本沼虾暴露于低氧((2±0.2)mg/L,8 h)而后恢复常氧水平((7±0.2)mg/L,2.5 h).结果显示:与对照组(保持常氧水平)相比,随着低氧暴露时间延长,日本沼虾肝胰腺和肌肉组织细胞色素氧化酶(CCO)和琥珀酸脱氢酶(SDH)活力显著下降(p0.05),延胡索酸还原酶(FRD)和乳酸脱氢酶(LDH)活力显著上升(p0.05);总抗氧化能力(T-AOC)和过氧化氢酶(CAT)活力显著上升(p0.05),超氧化物歧化酶(SOD)活力显著下降(p0.05).恢复常氧阶段,CCO,SDH,FRD,LDH,CAT和SOD活力逐渐恢复到正常水平,T-AOC在恢复常氧1 h时显著降低(p0.05),而后恢复到正常水平.低氧胁迫使得有氧代谢减弱,无氧代谢增强,以维持机体能量需求;T-AOC和CAT活力增加而SOD活力降低,是日本沼虾适应低氧环境所采取的一种抗氧化策略.

Effects of Hypoxia on Respiratory Metabolism and Antioxidant Capability of Macrobrachium nipponense

The effects of hypoxia stress on respiratory metabolism and oxidant metabolism of Macrobrachium nipponense were investigated,while the mechanism and the antioxidant response mechanism were primarily discussed.Adult shrimp were exposed to hypoxia((2±0.2) mg/L,8 h),followed by reoxygenation((7±0.2) mg/L,2.5 h).The results indicated that,with the duration of hypoxia exposure,activities of cytochrome c oxidase(CCO)and succinate dehydrogenase(SDH)of M.nipponense's hepatopancreas and muscle tissues were significantly lower compared with the control group(normoxia level)(p<0.05).Meanwhile,fumarate reductase(FRD)and lactate dehydrogenase(LDH)activities were significantly higher compared with the control group(p<0.05).Total antioxidant capability(T-AOC)and catalase(CAT)activities significantly increased(p<0.05),but superoxide dismutase(SOD)activities significantly decreased(p<0.05).Activities of CCO,SDH,FRD,LDH,CAT and SOD gradually returned to the normal level during reoxygenation,T-AOC significantly decreased in the first hour of recovery(p<0.05),then returned to control level.It indicated that the level of aerobic metabolism decreased while that of anaerobic metabolism increased which could maintain energy supply under hypoxia stress;Increment of T-AOC,CAT activities and decrease of SOD activities might be a antioxidant strategy to adapt hypoxia environment.