Respiratory Metabolism, Energy Utilization and Biochemical Responses of Juvenile Common Cuttlefish (Sepiella maindroni) to Hypoxia

To evaluate respiratory metabolism, energy utilization and enzymatic responses in common Chinese cuttlefish (Sepiella maindroni) to hypoxia, juvenile Chinese cuttlefish (26.66 ± 2.52 g) were exposed to a 1.4-L airtight respiration chamber until suffocation for 83.4 min. The results showed that dissolved oxygen (DO) was mainly consumed in the closed chamber and the rates of oxygen consumption and ammonia excretion decreased significantly with decreasing DO content. The suffocation point for the cuttlefish was 1.16 ± 0.10 mg·L-1. The O:N ratio increased significantly with decreasing DO content. The TP content in the hemolymph at 83.4 min was significantly lower than that at other time points; however, the highest GLU content was noted at 83.4 min, the highest AST and ALP activities occurred at 60 min and 83.4 min, respectively. These results indicated that although hypoxia inhibits respiratory metabolism, the cuttlefish demonstrated a capacity for energy mobilization under hypoxic conditions.