Production of industrial effluents have led to increased copper (Cu) pollution of aquatic ecosystems, impacting the physiology of aquatic vertebrates. Past work has shown that Cu exerts its toxicity by disruption ion regulation and/ or increasing oxidative stress. However, it remains unclear how Cu may influence aerobic metabolism and hypoxia tolerance, two possible targets of its toxicity. To address this issue, we exposed freshwater acclimated killifish (F. heteroclitus) to a 96 h Cu exposure at a target concentration of 100 μg L-1. We determined resting oxygen consumption (ṀO2), ṀO2max after exhaustive exercise, and followed ṀO2 for 3 h in post-exercise recovery in water with either no Cu or 100 μg L-1 Cu. We assessed hypoxia tolerance by determining the critical oxygen tension (Pcrit). It was found that killifish exposed to combined 96 h Cu exposure and Cu present during metabolic measurements, showed a significant decrease in ṀO2max and in aerobic scope (ṀO2max - ṀO2rest), compared to control fish. However, changes in blood and muscle lactate and muscle glycogen were not consistent with an upregulation of anaerobic metabolism as compensation for reduced aerobic performance in Cu exposed fish. Hypoxia tolerance was not influenced by the 96 h Cu exposure or by presence or absence of Cu during the Pcrit test. This study suggests that Cu differentially influences responses to changes in oxygen demand and oxygen availability.

中文翻译：

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96 h亚致死铜暴露对有毒鱼类（Fundulus heteroclitus）有氧运动范围和力竭恢复的影响。

工业废水的生产导致水生生态系统的铜（Cu）污染增加，影响了水生脊椎动物的生理。过去的工作表明，铜通过破坏离子调节和/或增加氧化应激发挥其毒性。然而，目前尚不清楚铜如何影响有氧代谢和低氧耐受性，这是其毒性的两个可能的目标。为解决此问题，我们将淡水驯化的kill鱼（F. heteroclitus）暴露于96 h Cu暴露，目标浓度为100μgL-1。我们确定了力竭运动后的静息耗氧量（ṀO2），ṀO2max，然后在无铜或100μgL-1 Cu的水中进行ṀO2运动后恢复3 h。我们通过确定临界氧张力（Pcrit）评估了低氧耐受性。结果发现，与对照鱼相比，暴露于96 h铜暴露下的比目鱼和代谢测量过程中存在的Cu显示showedO2max和有氧范围显着降低（ṀO2max-ṀO2rest）。然而，血液和肌肉乳酸和肌肉糖原的变化与厌氧代谢的上调不一致，这是对暴露于铜的鱼的有氧运动能力下降的补偿。缺氧耐受性不受96 h Cu暴露或Pcrit测试期间是否存在Cu的影响。这项研究表明，铜对氧气需求和氧气供应变化的反应有差异。血液和肌肉乳酸和肌糖原的变化与厌氧代谢的上调不一致，这是对暴露于铜的鱼的有氧运动能力下降的补偿。缺氧耐受性不受96 h Cu暴露或Pcrit测试期间是否存在Cu的影响。这项研究表明，铜对氧气需求量和氧气供应量变化的响应有不同的影响。血液和肌肉乳酸和肌糖原的变化与厌氧代谢的上调不一致，以补偿暴露于铜的鱼的有氧运动能力下降。缺氧耐受性不受96 h Cu暴露或Pcrit测试期间是否存在Cu的影响。这项研究表明，铜对氧气需求量和氧气供应量变化的响应有不同的影响。