PARENT SESSION

PW08 Aquatic Ecotoxicology II
Exhibit Hall
8:00 AM - Wednesday

(PW132) Aromatase Activity in Male and Female Adult Fathead minnows (Pimephales promelas) Exposed to Poultry Litter.

Pollack, S¹, Yonkos, L², Fisher, D², Ottinger, MA¹, ¹ Department of Animal and Avian Sciences, University of Maryland, College Park, Maryland, USA² Wye Research and Education Center, Queenstown, Maryland, USA

ABSTRACT- Research in our laboratory has previously reported on the presence of a number of potential endocrine disrupting compounds (EDCs) in poultry litter run-off from agricultural fields. In this study, we exposed reproductively mature adult male and female fathead minnows (N=96) in the laboratory to two concentrations of the poultry litter mixture that have been found to induce vitellogenin in males. 17- estradiol was used as a positive control in a separate group of animals of the same cohort. A reproductive assay was performed for twenty-one days and aromatase activity was analyzed in whole brain by measuring the release of radio-labelled tritiated water during aromatization of tritiated androstenedione. Results showed that aromatase activity was detectable in all fish. Aromatase activity did not differ significantly among males and females (p=0.5843). However, aromatase activity was found to differ significantly between the estradiol positive control group (E2) and the high poultry litter group (p =0.0098), as well as between the E2 group and the low poultry litter group (p=0.0141). Interestingly, the E2 treatment appeared to lower aromatase activity in both males and females whereas exposure to poultry litter, strongly induced aromatase in both sexes. Our results provide evidence for endocrine disrupting compounds present in both high and low poultry litter concentrations and these compounds are found in an aqueous environment. This suggests the presence of androgenic substances in the poultry litter causing the negative feedback of aromatase activity in the brain. This project was funded in part by the Maryland Agroecology Center, University of Maryland.

Key words: poultry litter , fathead minnow , aromatase , endocrine disruptors