This study aimed to verify the effects of interaction between different temperatures (~18, ~23 and ~ 28°C) with different dissolved oxygen levels (~2.0, ~4.5 and ~ 7.0 mg O₂ L^‐1) and different re‐oxygenation rates (0.5 and 5 hr) after hypoxia in pacu (Piaractus mesopotamicus). In experiment 1, fish were exposed to hypoxia, mild hypoxia or normoxia at low, medium or high temperature for 12 hr. In experiment 2, fish were exposed to hypoxia or normoxia at low, medium or high temperature for 12 hr and, after hypoxia, rapid or gradual re‐oxygenation was performed with a return to normoxia achieved in 0.5 or 5 hr. In experiment 1, blood glucose and pH levels were higher in the hypoxic treatment. The haematocrit and erythrocyte values were lower in mild hypoxia at low and high temperatures respectively. In experiment 2, blood lactate and glucose levels in rapid re‐oxygenation increased after 1 and 12 hr respectively. Twelve hours after rapid re‐oxygenation, haematological values were similar or lower than in the normoxia or gradual re‐oxygenation. In conclusion, exposure of pacu to hypoxic conditions increased blood glucose and pH levels (experiment 1). Additionally, 12 hr after gradual re‐oxygenation, blood variables returned to homeostatic levels (experiment 2).

中文翻译：

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Pacu（Piaractus mesopotamicus）幼鱼在不同温度下对缺氧和复氧的次级应激反应

这项研究旨在验证不同温度（〜18，〜23和〜28°C），不同溶解氧水平（〜2.0，〜4.5和〜7.0 mg O ₂ L ^-1）和不同再充氧之间相互作用的影响Pacu（Piaractus mesopotamicus）缺氧后发生率（0.5和5小时））。在实验1中，鱼在低温，中温或高温下暴露于缺氧，轻度缺氧或常氧状态12个小时。在实验2中，鱼在低温，中度或高温下暴露于缺氧或常氧状态12个小时，缺氧后，进行快速或逐步的重新充氧，并在0.5或5个小时内恢复至正常氧水平。在实验1中，低氧治疗的血糖和pH值较高。在低温和高温下，轻度缺氧的血细胞比容和红细胞值较低。在实验2中，快速补充氧的血液中的乳酸和葡萄糖水平分别在1和12小时后增加。快速再充氧后十二小时，血液学值与正常氧或逐渐再充氧时相似或更低。结论，将pacu暴露于低氧条件下会增加血糖和pH值（实验1）。此外，在逐渐重新充氧后12小时，血液变量恢复到稳态水平（实验2）。