Metabolic and Biochemical Responses of Juvenile Babylonia areolata to Hypoxia Stress

As an important aquaculture species, the marine snail <i>Babylonia areolata</i> is frequently subjected to fluctuation in dissolved oxygen concentration during farming and transportation processes. In the present study, we investigated the metabolic rates, transcription, and enzyme level responses of juvenile <i>B. areolata</i> exposed to long-term stress (144 h). The results showed that the mortality rate of juvenile <i>B. areolata</i> was higher in the 0.5 mg O₂/L group compared to the 2 mg O₂/L group. During the hypoxic stress period, both oxygen consumption and ammonia excretion rates were observed to be lower in juvenile <i>B. areolata</i> than those in the control group. As hypoxic stress duration prolonged, juvenile <i>B. areolata</i> demonstrated significantly elevated activities of pyruvate kinase (PK) and alkaline phosphatase (AKP), alongside reduced activities of lactic dehydrogenase (LDH), acid phosphatase (ACP), and superoxide dismutase (SOD). Significant changes in the expression levels of <i>PK</i> and <i>LDH</i> genes were observed during the hypoxic stress. The expression levels of <i>ACP</i> and <i>SOD</i> genes were significantly downregulated, while juvenile <i>B. areolata</i> exhibited elevated <i>AKP</i> gene expression levels under 0.5 mg O₂/L. Our findings suggest that under long-term exposure to hypoxia, <i>B. areolata</i> failed to maintain energy homeostasis and suffered biochemical disruptions, leading to a reduction in survival. The mortality rate of <i>B. areolata</i> can be substantially decreased by ensuring that transportation time does not exceed 48 h.