Aims: The phytoestrogen, genistein and β-sitosterol, naturally occurring compounds found in soy products and pulp and paper mill effluent, respectively, could act as endocrine disrupting compounds (EDC) in the environment. The aim of this study was to evaluate the effects of β-sitosterol and genistein on the early life stages of Kutum (Rutilus kutum), specifically developing post-fertilized embryos. Materials and Methods: In this experimental study, Kutum’s fertilized egg exposed to 3 different levels of genistein and β-sitosterol (10, 50, 500ng.l-1, respectively) up to 7 days post-fertilization (dpf). At the end of the research period, newly hatched larvae were sampled and testosterone (T), 17β-estradiol (E2), Aromatase and ethoxyresorufin-O-deethylase (EROD) were measured according to standard protocols. One-way analysis of variance (ANOVA), Duncan multiple range test and SPSS 17 software were used for data analyses. Findings: A high level of genistein lead to increased 17β-estradiol, testosterone concentration and aromatase activity. Also, β-sitosterol treated embryos (500ng.l-1) showed a high level of testosterone and EROD as compared to the control group. While other treatment had no significant effect. Conclusion: It seems that β-sitosterol and genistein could effect on the endocrine system of Kutum embryos by altering steroid biosynthesis and disturb enzyme activity. So it could lead to change the population structure and reduce reproduction performance of Kutum in the long period.
