PARENT SESSION

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

(PW137) Effects of poultry litter-associated contaminants on fathead minnow reproduction.

Yonkos, L¹, Fisher, D¹, Van Veld, P², ¹ University of Maryland - Wye Research and Education Center, Queenstown, MD, USA² College of William and Mary - Virginia Institute of Marine Science, Gloucester Point, VA, USA

ABSTRACT- Nearly 1.6 billion lbs of poultry litter are generated annually as a by-product of the Delmarva poultry industry. Disposal, accomplished by application to fields as fertilizer, results in runoff of litter-associated contaminants into receiving waters following rain events. Of particular concern are the natural steroid hormones 17-estradiol (E2), estrone, and testosterone, present in dry litter at concentrations of ∼200 g/Kg. Aqueous concentrations of steroids in runoff can exceed 100 ng/L. Previous assays performed in our laboratory have shown that contaminants in poultry litter are capable of inducing the production of vitellogenin (Vtg) in adult male fathead minnows (Pimephales promelas) at environmentally relevant exposure levels. We performed a Fathead Minnow Reproduction Assay to investigate the effects of poultry litter-associated contaminants on fecundity and hatching success. Replicate breeding groups (2 male and 4 female) were exposed to two aqueous poultry litter solutions (E2 levels of ∼ 35 and 70 ng/L) and to positive (100 ng E2/L) and well water controls for 21 days. Eggs were collected and tabulated daily, then maintained in control water until hatched. Vtg induction occurred in 100% of males (n=8) from the E2 control and high poultry litter treatments, and in 37% of males from the low poultry litter treatment. No Vtg induction occurred in control males. Despite elevated Vtg (considered a clear indicator of exposure to an estrogenic stimulus) reproduction was not inhibited in either poultry litter treatment. Assay results suggest that induction of Vtg in male fathead minnows does not necessarily lead to a consequent reduction in reproductive capability. Implications of this finding will be discussed.

Key words: endocrine disruption, poultry litter, Pimephales promelas, reproduction assay