Magnuson Jason T, Fuller Neil, McGruer Victoria, Huff Hartz Kara E, Acuña Shawn, Whitledge Gregory W, Lydy Michael J, Schlenk Daniel
Department of Environmental Sciences, University of California, Riverside, CA, 92521, United States.
Center for Fisheries, Aquaculture and Aquatic Sciences, Southern Illinois University, Carbondale, IL, 62901, United States.
Environ Pollut. 2023 Feb 1;318:120938. doi: 10.1016/j.envpol.2022.120938. Epub 2022 Dec 23.
Projected water temperature increases based on predicted climate change scenarios and concomitant pesticide exposure raises concern about the responses of aquatic organisms. To better understand the effect of pesticide mixtures and influence of water temperature to fish, juvenile Chinook salmon (Oncorhynchus tshawytscha) were dietarily exposed to a mixture of legacy and current use pesticides (p,p'-DDE, bifenthrin, chlorpyrifos, esfenvalerate, and fipronil) at concentrations detected from field-collected prey items in the Sacramento-San Joaquin Delta, California (Delta) and exposed under current and predicted future water temperature scenarios, 11, 14, or 17 °C, for 14 days. The expression of a subset of genes (deiodinase 2-dio2, gonadotropin releasing hormone 2-gnrh2, and catechol-o-methyltransferase-comt) involved in neuroendocrine, dopaminergic, and olfactory function previously shown to be altered by individual pesticide exposures germane to this study were determined and olfactory function assessed using a Y-maze behavioral assay. When total body burdens of pesticides were measured, a significant decrease in dio2 expression was observed in Chinook salmon exposed at 14 °C compared to fish kept at 11 °C. Increases in gnrh2 expression were also observed in fish exposed to 14 °C. Similarly, increases in comt expression was noted at 14 and 17 °C. Additionally, altered expression of all transcripts was observed, showing interactions between temperature and individual pesticide concentrations. Chinook salmon spent significantly more time actively avoiding the odorant arm at baseline conditions of 11 °C in the Y-maze. At higher temperatures, Chinook spent significantly more time not making a choice between the odorant or clean arm following exposure to the low pesticide mixture, relative to 11 °C. These results suggest that dietary exposure to pesticide mixtures can potentially induce neuroendocrine effects and behavior. Impaired olfactory responses exhibited by Chinook salmon could have implications for predator avoidance in the wild under increased temperature scenarios and impact populations in the future.
基于预测的气候变化情景所预计的水温升高以及随之而来的农药暴露，引发了人们对水生生物反应的担忧。为了更好地理解农药混合物的影响以及水温对鱼类的影响，将幼年奇努克鲑鱼（Oncorhynchus tshawytscha）通过饮食暴露于传统和当前使用的农药混合物（p,p'-滴滴伊、联苯菊酯、毒死蜱、乙氰菊酯和氟虫腈）中，这些农药的浓度是在加利福尼亚州萨克拉门托 - 圣华金河三角洲（三角洲）野外采集的猎物中检测到的，并在当前和预测的未来水温情景（11、14或17°C）下暴露14天。测定了先前已表明会因与本研究相关的个别农药暴露而改变的、参与神经内分泌、多巴胺能和嗅觉功能的一组基因（脱碘酶2 - dio2、促性腺激素释放激素2 - gnrh2和儿茶酚 - O - 甲基转移酶 - comt）的表达，并使用Y迷宫行为试验评估嗅觉功能。当测量农药的全身负荷时，与饲养在11°C的鱼类相比，在14°C下暴露的奇努克鲑鱼中观察到dio2表达显著下降。在暴露于14°C的鱼类中也观察到gnrh2表达增加。同样，在14°C和17°C时注意到comt表达增加。此外，观察到所有转录本的表达都发生了变化，表明温度与个别农药浓度之间存在相互作用。在Y迷宫中，奇努克鲑鱼在11°C的基线条件下显著花费更多时间主动避开有气味的臂。在较高温度下，相对于11°C，奇努克鲑鱼在暴露于低农药混合物后，在有气味或清洁臂之间不做选择的时间显著增加。这些结果表明，通过饮食暴露于农药混合物可能会潜在地诱导神经内分泌效应和行为。奇努克鲑鱼表现出的嗅觉反应受损可能会对温度升高情景下野外的捕食者规避产生影响，并在未来影响种群数量。
