The dissolved oxygen (DO) level is particularly important for marine benthic crustaceans. In Scylla paramamosain, the DO level plays an important role in regulating immune and metabolic responses. The present study assessed whether the effects of hypoxia on the resistance of S. paramamosain to Vibrio alginolyticus are related to the changes in energy metabolism. In hypoxic S. paramamosain, the immune-related genes, Janus kinase, signal transducer and activator of transcription, Relish, and Astakine were significantly downregulated in hemocytes. In contrast, hypoxia inducible transcription factor-1α, lactate dehydrogenase (LDH), and prophenol oxidase mRNA levels were significantly upregulated in hypoxic S. paramamosain. The levels of pyruvic acid and lactic acid were significantly increased in hypoxic S. paramamosain, this may be closely related to the increases in pyruvate kinase and LDH activities. A significant decrease in hepatic glycogen was observed in hypoxic S. paramamosain, and the breakdown of hepatic glycogen might be the reason why no significant differences in glucose levels were found between the normoxic and hypoxic groups. In addition to the changes in metabolism-related enzyme activities, the levels of phenol oxidase (PO) activity and apoptosis increased significantly, while total hemocyte counts (THC) were significantly decreased in hypoxic S. paramamosain. After challenge with V. alginolyticus, the bacterial count was significantly lower in the hypoxic group than in the normoxic group, while the mortality rate was higher in hypoxic S. paramamosain. The decrease bacterial count might be associated with the changes in the metabolism of hypoxic S. paramamosain. These results suggested that the resistance of S. paramamosain to V. alginolyticus could be weakened when the host was under hypoxic conditions, and the weakened resistance might be related to changes in immune-related gene expression, THC, PO activity, hemocyte apoptosis, and energy metabolism.

溶解氧（DO）含量对于海洋底栖甲壳类动物特别重要。在Sylla paramamosain中，DO水平在调节免疫和代谢反应中起着重要作用。本研究评估了缺氧对S. paramamosain对溶藻弧菌的抗性是否与能量代谢的变化有关。在缺氧的副链霉菌中，免疫相关基因，Janus激酶，信号转导和转录激活因子，Relish和Astakine在血细胞中显着下调。相比之下，缺氧诱导转录因子1α，乳酸脱氢酶（LDH）和前酚氧化酶mRNA水平在缺氧副沙门菌中明显上调。低氧副生沙门氏菌中丙酮酸和乳酸水平显着升高，这可能与丙酮酸激酶和LDH活性的升高密切相关。缺氧副链霉菌肝糖原的肝糖显着减少。，而肝糖原的分解可能是在常氧和低氧组之间未发现血糖水平显着差异的原因。除代谢相关酶活性的变化外，低氧副生沙门氏菌中酚氧化酶（PO）活性和凋亡水平显着增加，而总血细胞计数（THC）则显着降低。用溶藻弧菌攻击后，低氧组的细菌数显着低于常氧组，而低氧副杀伤链球菌的死亡率更高。细菌数量的减少可能与低氧副生沙门氏菌的代谢变化有关。这些结果表明，当宿主处于低氧条件下时，副花色葡萄球菌对溶藻弧菌的抗性可能会减弱，并且这种抗性可能与免疫相关基因表达，THC，PO活性，血细胞凋亡和能量代谢。