Effect of the exogenous soyabean phyto-oestrogen genistein on sperm quality, ATP content and fertilization rates in channel catfish Ictalurus punctatus (Rafinesque) and walleye Sander vitreus (Mitchill)

This Study examined whether the soya phyto-oestrogen genistein would have an effect on spermatozoa quality and in vitro Fertilization capacity in mature channel catfish lctalurus punctotus or walleye Sander vitreus. For both species, motility time and motility rank were significantly different among treatment groups and control, with higher genistein concentrations producing significantly lower motility time and motility rank (P <= 0.01). Walleye and channel catfish ATP content was significantly lower compared to control treatments at several incubation concentrations and was significantly related to fertilization rate. Fertilization rate was significantly dependant on genistein incubation concentrations (P <= 0.01). Additionally. logistic regression showed a significant negative relation between genistein concentration and fertilization in channel catfish (P <= 0.01). These results establish that genistein could play a role in reproductive performance within aquaculture species. In addition, these findings warrant further examination of the impact of phyto-oestrogens in broodstock feeds. (C) 2008 The Authors. Journal compilation (C) 2008 The Fisheries Society of the British Isles.