EMSG37-BAYER: Participation of Bayer CropScience in Phase 1A and 1B of the OECD validation work on the “Non-Spawning Fish Screening Assay” for the detection of endocrine active substances according to the OECD test protocol (ENV/JM/TG/EDTA(2002)5)

Description

In a 21-day-assay (phase 1 B), sexually mature female and male fathead minnows (Pimephales promelas) were exposed to a weak estrogen agonist, or a weak aromatase inhibitor, under flow-through conditions. Three different test-compound concentrations, a
water-only control, and a corresponding positive control (strongly active compound), were tested with replication. Spawning of fish was made possible by the addition of artificial spawning substrates. The following endpoints were investigated: plasma vitellogenin levels, secondary sexual characteristics, reproductive output and gonad histopathology. The results indicated that the Fish Screening Assay with fathead minnow can detect the effects of both weak and strong estrogenic and aromatase inhibitor compounds, respectively, on the basis of the parameters selected. Some of the parameters (plasma vitellogenin, gonad histopathology and secondary sex characteristics) were also suitable for detecting a strongly androgenic compound, as was shown during validation phase 1 A. Therefore, the Fish Screening Assay appears to be a reliable and sensitive method. It is concluded that the Fish Screening Assay with fathead minnow can be used, after finalization of validation work, for detecting endocrine-modulating compounds (estrogenic, androgenic and aromatase inhibitors) and for triggering further tailor-made fish (partial) lifecycle-
experiments.