Comparison of ethinylestradiol and nonylphenol effects on reproduction of Chinese rare minnows ( Gobiocypris rarus)

Abstract

Breeding pairs of rare minnows were exposed to 5, 10, 20 μg/L 4-nonylphenol (NP) or 4 ng/L 17α-ethinylestradiol (EE 2) for 21 days. Among reproductive parameters investigated, fecundity, fertility, and laying interval were significantly affected by 4 ng/L EE 2, but were not affected at any exposure level of NP. These effects coincided with male feminization, ova-testis, increased plasma VTG in both males and females as well as the accumulation of eosinophilic material in kidneys and livers. Histopathologic evaluation revealed severe kidney lesions in both EE 2 and NP-exposed fish. The bioassay succeeded in demonstrating that EE 2 was several orders of magnitude more potent than the industrial chemical NP. The rare minnow was more sensitive to EE 2 than medaka, but comparable to zebrafish in terms of sensitivity. The results of the present investigation indicated that a short-term reproductive bioassay is feasible using the Chinese rare minnow as the test species.