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United States Department of Agriculture

Agricultural Research Service

Research Project: METABOLIC FATE OF CHEMICAL AND BIOLOGICAL CONTAMINANTS

Location: Animal Metabolism-Agricultural Chemicals Research

Title: Modulation of estrogenic exposure effects mediated through temperature and dietary regimens in male fat head minnows

Authors
item Shappell, Nancy
item Feifarek, David -
item Rearick, Daniel -
item Bartell, Stephen -
item Schoenfuss, Heiko -

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: June 28, 2013
Publication Date: N/A

Technical Abstract: A plethora of studies has examined the biological effects of environmental estrogens on fathead minnows. However, in many cases results from environmental studies do not match the expectations from prior laboratory exposures, which usually are designed to minimize confounding factors such as temperature and food availability. In contrast, the biological effects observed in fathead minnow exposures to environmental estrogens in aquatic ecosystems represent the totality of environmental stressors and seldom match laboratory conditions. To simulate the effects of estrogenic exposure in the wild, we exposed male fathead minnows to low (15 ng/L) and high (100 ng/L) concentrations of estrone for 21 days in a flow-through system. Half of the minnows were maintained at 17 C the other half at 26 C, more typical of controlled laboratory conditions. Furthermore, each temperature group was subdivided into a restricted diet group and an ad libitum group. At the end of the 21-day exposure, we examined morphometric endpoints (condition factor, GSI, HSI, secondary sex characteristics), physiological data (vitellogenin, blood sugar, cortisol) and histopathology of liver and testis. The entire experiment was replicated once. The GSI was significantly reduced in all ad libitum feed treatments with a concurrent increase in body condition factor. As expected, plasma vitellogenin concentrations were elevated (P < 0.05) in all high estrone treatments, yet those fish maintained at 26 C were higher than those at 17 C (P < 0.05). Blood sugar concentrations were also significantly increased in high estrone treatments, again with significantly higher concentrations found in fish in the warmer water suggesting greater metabolic stress. This study highlights the impacts of multiple stressors and modulating effects of environmental conditions on the expression of biomarkers associated with exposure to environmental estrogens. In order to realistically expect concordance between laboratory and field investigations of the biological effects of contaminants of emerging concern more attention needs to be focused on establishing environmentally relevant exposure conditions.

Last Modified: 7/31/2014
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