低氧胁迫对斑石鲷能量代谢、肝脏抗氧化能力和组织形态变化的影响

Effects of hypoxic stress on the energy metabolism, hepatic antioxidant capacity and histomorphology in Oplegnathus punctatus

  • 摘要:
    目的 探究低氧胁迫对深远海养殖良种斑石鲷抗氧化能力、能量代谢及组织形态的影响。
    方法 设立对照组、临界氧分压组 (Pcrit 组)、失去平衡点组 (LOE组) 和恢复组,分析了两种规格 小规格:(50.47±0.26) g;大规格:(200.18±1.33) g 斑石鲷在低氧胁迫下肝脏抗氧化酶活性、糖脂代谢和组织形态学变化。
    结果 低氧胁迫过程中两种规格斑石鲷的肝脏乳酸脱氢酶,丙酮酸激酶,磷酸果糖激酶和己糖激酶活性及乳酸含量呈显著上升趋势,在LOE处达到最高值,且200 g斑石鲷显著高于50 g斑石鲷。肝脏糖原含量在低氧胁迫过程中呈逐渐降低趋势,50 g斑石鲷在LOE处显著降低,而200 g斑石鲷无显著变化。肝脏超氧化物歧化酶、过氧化氢酶、谷胱甘肽过氧化物酶、谷草转氨酶、谷丙转氨酶活性和丙二醛含量呈逐渐升高变化趋势,均在LOE显著增高,50 g斑石鲷显著低于200 g斑石鲷。肝脏脂蛋白脂肪酶和脂肪酸合成酶活性,在低氧胁迫过程中无显著变化。同时两种规格斑石鲷肝细胞偏移、溶解、固缩比例均显著增加,正常形态肝细胞比例逐渐减小。恢复正常溶解氧24 h后,上述指标均与对照组无显著差异。
    结论 本实验中低氧胁迫显著影响斑石鲷糖代谢,肝脏抗氧化能力和组织形态结构,主要通过无氧酵解来满足低氧胁迫条件下能量需求,200 g斑石鲷比50 g斑石鲷变化更为显著。相关结果为斑石鲷高效养殖提供了基础理论依据和数据支撑。

     

    Abstract: Dissolved oxygen is a crucial environmental factor that significantly influences the survival, growth, and development of aquatic organisms. Fish species are diverse, and their physiological responses to hypoxic stress vary considerably. To investigate the impact of hypoxic stress on the antioxidant capacity, energy metabolism, and tissue morphology of Oplegnathus punctatus, a valuable species for deep-sea aquaculture, this study examined alterations in hepatic antioxidant enzyme activities, glycolipid metabolite levels, and tissue morphology in two size groups (200 g and 50 g) of O. punctatus under critical oxygen partial pressure (Pcrit) and loss of equilibrium (LOE) conditions. The results revealed that under hypoxic stress reaching LOE, the activities of lactate dehydrogenase (LDH), pyruvate kinase (PK), phosphofructokinase (PFK), and hexokinase (HK), as well as lactate content, significantly increased (P<0.05) in both size groups, with the 200 g group showing greater increases in energy metabolism enzyme activities compared to the 50 g group. Hepatic glycogen content decreased during hypoxia, with a significant reduction in the 50 g group at LOE (P<0.05), while the 200 g group showed no significant change. Concurrently, the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) in the liver were significantly elevated (P<0.05), while malondialdehyde (MDA) content also increased significantly (P<0.05), reflecting heightened oxidative stress levels. Notably, the 50 g group exhibited smaller increases in antioxidant enzyme activities compared to the 200 g group. In contrast, the activities of lipoprotein lipase (LPL) and fatty acid synthase (FAS) showed no significant changes during hypoxia (P>0.05). Furthermore, the proportions of hepatocyte migration, lysis, and pyknosis significantly increased in both size groups, whereas the proportion of normal hepatocytes gradually decreased. All measured parameters returned to control levels 24 hours after restoration of normal dissolved oxygen. In conclusion, hypoxic stress significantly affected the glycolysis, hepatic antioxidant capacity, and tissue morphology of O. punctatus in this experiment. The fish primarily relied on anaerobic glycolysis to meet energy demands under hypoxic conditions, with the 200 g group exhibiting more pronounced changes compared to the 50 g group. These results provide a theoretical foundation and data support for the effectively management of O. punctatus in captivity.

     

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