Abstract：
Respiratory plasticity is a beneficial response to chronic hypoxia in fish. Red drum, a teleost that commonly experiences hypoxia in the Gulf of Mexico, have shown respiratory plasticity following sublethal hypoxia exposure as juveniles, but implications of hypoxia exposure during development are unknown. We exposed red drum embryos to hypoxia (40% air saturation) or normoxia (100% air saturation) for 3 days post fertilization (dpf). This time frame encompasses hatch and exogenous feeding. At 3 dpf, there was no difference in survival or changes in size. After the 3-day hypoxia exposure, all larvae were moved and reared in common normoxic conditions. Fish were reared for ∼3 months and effects of the developmental hypoxia exposure on swim performance and whole-animal aerobic metabolism were measured. We used a cross design wherein fish from normoxia (N=24) were exercised in swim tunnels in both hypoxia (40%, n=12) and normoxia (100%, n=12) conditions, and likewise for hypoxia-exposed fish (n=10 in each group). Oxygen consumption, critical swim speed (Ucrit), critical oxygen threshold (Pcrit) and mitochondrial respiration were measured. Hypoxia-exposed fish had higher aerobic scope, maximum metabolic rate, and higher liver mitochondrial efficiency relative to control fish in normoxia. Interestingly, hypoxia-exposed fish showed increased hypoxia sensitivity (higher Pcrit) and recruited burst swimming at lower swim speeds relative to control fish. These data provide evidence that early hypoxia exposure leads to a complex response in later life.
摘要：
呼吸可塑性是对鱼类慢性缺氧的有益反应。红鼓,通常在墨西哥湾经历缺氧的硬骨鱼，在青少年亚致死缺氧暴露后表现出呼吸可塑性，但是在发育过程中暴露于低氧的影响是未知的。我们在受精后（dpf）将红鼓胚胎暴露于缺氧（40％空气饱和度）或常氧（100％空气饱和度）3天。这个时间框架包括孵化和外源喂养。在3dpf时，生存率无差异,大小无变化.3天缺氧暴露后,所有幼虫都在普通常氧条件下移动和饲养。鱼饲养了3个月，并测量了发育缺氧暴露对游泳表现和整个动物有氧代谢的影响。我们使用了交叉设计，其中来自常氧（N=24）的鱼在两个缺氧的Blazka游泳隧道中游（40％，n=12)和常氧(100%，n=12),对于暴露于缺氧的鱼类（每组N=20，n=10）也是如此。耗氧量,临界游泳速度(Ucrit)，临界氧阈值(Pcrit)，并测量线粒体呼吸。低氧暴露鱼类有较高的有氧范围，最大代谢率，相对于常氧下的对照鱼，肝脏线粒体效率更高。有趣的是,缺氧暴露的鱼表现出增加的缺氧敏感性（较高的Pcrit），相对于对照鱼，招募以更低的游泳速度游泳。这些数据提供了低氧暴露在以后的生活中导致复杂的反应的证据。
