Male goldfish reproductive behaviour and physiology are severely affected by exogenous exposure to 17β-estradiol

Abstract

Mature male goldfish were exposed to different concentrations of the natural hormone 17β-estradiol (E 2). Two methods of exposure were employed, via ingestion at 0, 1, 10 and 100 μg/g food and via the water at 0, 1 and 10 μg/l. The fish were exposed for 24–28 days during the spawning period. The males were then paired with an artificially induced, spawning female and their sexual behaviour was observed during a 15 min period. The physiological status of the fish was also examined with respect to GSI, presence of milt and spawning tubercles and the blood plasma concentration of E 2. Despite the relatively short exposure period, exposure to physiological levels of E 2 was shown to severely affect the male goldfish reproductive behaviour and physiology. In conclusion, the results from this study and the ability to interpret the effects on this well-studied species, show that the effects of E 2, and possibly other estrogenic EDCs, have severe effects at several vital levels of male goldfish reproduction. The results also suggests that the hormone E 2 can act as an endocrine disrupting chemical (EDC) in the environment.