Mehdi Hossein, Dickson Fiona H, Bragg Leslie M, Servos Mark R, Craig Paul M
Department of Biology, University of Waterloo, N2L 3G1, Waterloo, ON, Canada.
Department of Biology, University of Waterloo, N2L 3G1, Waterloo, ON, Canada.
Comp Biochem Physiol B Biochem Mol Biol. 2018 Oct;224:270-279. doi: 10.1016/j.cbpb.2017.11.011. Epub 2017 Nov 22.
The objective of this study was to assess the effects of municipal wastewater treatment plant effluent on the energetics and stress response of rainbow darter (Etheostoma caeruleum). Male and female rainbow darter were collected upstream and downstream of the Waterloo WWTP in the Grand River watershed, ON, Canada. To assess the effects of wastewater treatment plant effluent on whole-body and tissue specific metabolic capacity, closed-chamber respirometry and muscle-enzyme activity analyses were performed. Plasma cortisol was also collected from fish before and after an acute air-exposure stressor to evaluate the cortisol stress response in fish exposed to additional stressors. Male and female rainbow darter collected downstream of the effluent had higher oxygen consumption rates, while differences in enzyme activities were primarily associated with sex rather than collection site. No impairment in the cortisol stress response between downstream and upstream fish was observed, however baseline cortisol levels in female fish from the downstream site were significantly higher compared to other baseline groups. Stress-induced cortisol levels were also higher in female fish from both sites when compared to their male counterparts. Overall, this study demonstrates that chronic exposure to WWTP effluent impacts whole-body metabolic performance. This study was also able to demonstrate that sex-differences are a key determinant of various metabolic changes in response to physiological stress, thereby, providing a novel avenue to be considered and further explored.
本研究的目的是评估城市污水处理厂出水对虹彩镖鲈（Etheostoma caeruleum）能量学和应激反应的影响。在加拿大安大略省格兰德河流域滑铁卢污水处理厂的上游和下游采集了雄性和雌性虹彩镖鲈。为了评估污水处理厂出水对全身和组织特异性代谢能力的影响，进行了密闭室呼吸测定和肌肉酶活性分析。还在急性空气暴露应激源前后从鱼体采集血浆皮质醇，以评估暴露于额外应激源的鱼的皮质醇应激反应。采集于出水下游的雄性和雌性虹彩镖鲈耗氧率更高，而酶活性差异主要与性别而非采集地点有关。未观察到下游和上游鱼类之间皮质醇应激反应受损，然而，来自下游地点的雌性鱼类的基线皮质醇水平与其他基线组相比显著更高。与雄性对应物相比，两个地点的雌性鱼类应激诱导的皮质醇水平也更高。总体而言，本研究表明，长期暴露于污水处理厂出水会影响全身代谢性能。本研究还能够证明，性别差异是各种代谢变化响应生理应激的关键决定因素，从而提供了一条需要考虑和进一步探索的新途径。
