Department of Fisheries, Faculty of Natural Resources, University of Tehran, Karaj, Iran.
Department of Fisheries, Faculty of Natural Resources, University of Tehran, Karaj, Iran.
Chemosphere. 2014 Aug;108:396-404. doi: 10.1016/j.chemosphere.2014.02.038. Epub 2014 Mar 12.
The stocks of Caspian roach (Rutilus rutilus), an economically important species in the Caspian Sea, are depleting. Each year millions of artificially produced fingerlings of this species are restocked in the mouth of rivers of the Southern Caspian Sea (e.g. Qare Soo River), where they are exposed to pesticides originating from regional rice and orchard fields. This early exposure to pesticides could affect the hypo-osmoregulatory ability of juvenile fish. Thus, in this study, Caspian roach fingerlings were exposed to environmentally-relevant concentrations of the organophosphate insecticide diazinon for 96 h in fresh water and then transferred to diazinon-free brackish water (BW) for another 96 h. We report that cortisol and glucose levels were significantly increased in all diazinon treatments at all sampling time points in comparison to the control group. Moreover, the thyroid hormone levels of TSH, T4, and T3 significantly decreased in diazinon-exposed fish even after the transfer to BW. The electrolytes were differentially affected during the exposure to diazinon and after the transfer to BW. The number of chloride cells in the gill tissue was significantly increased during diazinon exposure at the higher concentrations and decreased to control levels after transfer to BW. Finally, gill and kidney tissues showed many histopathological changes in diazinon-exposed fish even after 240 h in BW. These results suggest that the release of Caspian roach fingerlings into the diazinon-contaminated Caspian Sea regions may alter their physiology and jeopardize their survival, which could lead to a failure in rebuilding the Caspian roach stocks in the Caspian Sea.
里海拟鲤（Rutilus rutilus）是里海经济上重要的物种，其种群正在减少。每年，数以百万计的这种人工养殖的鱼苗被重新放养到里海南部河口（如 Qare Soo 河），而这些鱼苗会接触到来自该地区稻田和果园的农药。这种早期接触农药可能会影响幼鱼的低渗调节能力。因此，在这项研究中，里海拟鲤鱼苗在淡水环境中暴露于环境相关浓度的有机磷杀虫剂二嗪农 96 小时，然后转移到无二嗪农的半咸水（BW）中再暴露 96 小时。我们报告说，与对照组相比，所有二嗪农处理组在所有采样时间点的皮质醇和葡萄糖水平都显著升高。此外，即使在转移到 BW 后，暴露于二嗪农的鱼的甲状腺激素 TSH、T4 和 T3 水平也显著降低。在暴露于二嗪农和转移到 BW 后，电解质的水平受到不同的影响。在较高浓度下，暴露于二嗪农时，鳃组织中的氯离子细胞数量显著增加，而转移到 BW 后则降至对照水平。最后，即使在 BW 中暴露 240 小时后，暴露于二嗪农的鱼的鳃和肾脏组织也出现了许多组织病理学变化。这些结果表明，将里海拟鲤鱼苗释放到受二嗪农污染的里海地区可能会改变它们的生理机能，危及它们的生存，从而导致里海拟鲤种群在里海的重建失败。
