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A SHORT-TERM REPRODUCTION TEST WITH THE FATHEAD MINNOW (PIMEPHALES PROMELAS): L METHODS DESCRIPTION
Citation:
Kahl, M D., K M. Jensen, J J. Korte, AND G T. Ankley. A SHORT-TERM REPRODUCTION TEST WITH THE FATHEAD MINNOW (PIMEPHALES PROMELAS): L METHODS DESCRIPTION. Presented at SETAC 8th Annual Meeting, Bloomington, MN, April 13-14, 2000.
Description:
Due to the time and expense associated with full life-cycle testing, most current toxicity tests with fish do not explicity consider reproductive output as an endpoint but, rather, focus on early life-stage survival and development. However, there are classes of chemicals that could adversely impact reproduction at concentrations below those that affect development. Further, estimates of the effects of toxic compounds on reproductive output can be very useful to the ecological risk assessment process. A short-term reproduction test with the fathead minnow (Pimephales promelas), was developed with these goals in mind. An important impetus in selection of many of the specific endpoints used in the assay was a need for the test to detect disruption in endocrine function controlled by estrogens and/or androgens. The test is initiated with reproductively-mature animals, and is comprised of a pre-exposure phase of 14 to 21 d, followed by a chemical exposure of up to 21 d. Reproductive behavior, secondary sexual characteristics and fecundity are assessed over the course of the test, and eff fertility and early development of the resultant embryos also can be determined. At conclusion of the test, several endpoints specifically associated with estrogenic/androgenic controls on reproduction are assessed, including plasma concentrations of vitellogenin and sex steroids (B-estradiol, testosterone, 11-ketotestosterone) and gonadal status (relative weight, histopathology). The test described herein is relatively cost-effective, and can be completed in a time frame which is a fraction of that required to complete a traditional full life-cycle study. Although many of the endpoints are focused upon identifying endocrine-disrupting chemicals, the basic test should be applicable to other risk assessment scenarios.