As a part of their unique life cycle, most salmonids undergo a transition from fresh water to salt water requiring various adjustments in metabolism, osmoregulation and ion regulation. Exposure to pesticides may affect the acclimation of juvenile salmonids to salt water during downstream migration to estuaries. Using the Caspian Sea as a model waterbody, the present study aimed to determine how the toxicity of the organophosphate pesticide chlorpyrifos (CPF) impacts saline acclimation of rainbow trout (Oncorhynchus mykiss). We pre-exposed 4-month-old fish to nominal concentrations of 0, 20, 40, 80, 160 μg/L of CPF for seven days, and then gradually to salinity (12 ppt) for another seven days. Mortality, levels of cortisol, T3 and T4 in serum, and expression of genes involved in gill ion transport (Na⁺/K⁺ATPase α1a and α1b) and liver xenobiotic detoxification (Glutathione-S-Transferase pi, GST) were measured at day fourteen. Cortisol concentrations in serum were not changed by CPF exposure in freshwater, but serum T3 increased up to three fold relative to controls in freshwater. Following salinity acclimation, T3 and T4 concentrations in the serum were both increased up to 2.5 and 8.8 fold in animals treated with CPF followed by saltwater. Na+/K + ATPase α1a and α1b mRNA in gill were unchanged by CPF treatment in freshwater but trended higher in CPF-treated animals after salinity acclimation. Hepatic mRNA of GST was significantly increased following exposure to CPF but was unchanged after saltwater exposure. Although saltwater treatment reduced the acute lethality of CPF, changes in T3/T4 suggest sublethal impacts may occur in CPF-treated fish after they acclimate to Caspian seawater.

作为其独特生命周期的一部分，大多数鲑鱼经历了从淡水到盐水的转变，需要对新陈代谢，渗透调节和离子调节进行各种调整。在下游向河口迁移的过程中，接触农药可能会影响少年鲑鱼对盐水的适应。本研究以里海为模型水体，旨在确定有机磷酸盐农药毒死rif（CPF）的毒性如何影响虹鳟（Oncorhynchus mykiss）的盐碱适应。我们将4个月大的鱼以0、20、40、80、160μg/ L的CPF标称浓度预先暴露了7天，然后再逐渐盐化（12 ppt）持续了7天。死亡率，血清中皮质醇，T3和T4的水平以及g离子转运相关基因的表达（Na⁺ / K ⁺在第14天测量ATPaseα1a和α1b）和肝异物解毒（谷胱甘肽-S-转移酶pi，GST）。淡水中CPF的暴露不会改变血清中皮质醇的浓度，但相对于淡水中的对照，血清T3最多可增加三倍。盐度适应后，在用CPF和盐水处理的动物中，血清中的T3和T4浓度均增加至2.5倍和8.8倍。在淡水中进行CPF处理后，g中的Na + / K + ATPaseα1a和α1bmRNA不变，但在盐度适应后，经CPF处理的动物中的Na + / K + ATPaseα1b和α1bmRNA升高。暴露于CPF后，GST的肝mRNA显着增加，但暴露于盐水后，其GST不变。尽管盐水处理降低了CPF的急性致死性，