Effect of genistein, daidzein and coumestrol on sex-related genes expression in Russian sturgeon (Acipenser gueldenstaedtii)

Phytoestrogens are compounds of estrogenic properties, present in high concentrations in sturgeon aquafeeds due to common utilization of the soybean and its derivatives for fish feed production. The mechanism of those compounds and their effect on sex-related gene expression is poorly understood. Therefore, this study aimed to examine the expression of the amh, ar, cyp19, dmrt1, erα, erβ, foxl2, sox9, star, vasa and vtg genes in the gonads, the brain and the liver of one-year-old Russian sturgeons exposed for 265 days to daidzein, genistein and coumestrol administrated as feed additives in the concentration of 10,000, 500 and 10 mg kg⁻¹ feed, respectively. In the brain tissue the most significant effect of the studied compounds was observed. With the exception of a few females from Genistein and Coumestrol groups, the expression patterns of erα, vtg, amh, foxl2, sox9, cyp19 and ar in the brain were altered to the greatest extent in the individuals from experimental groups in comparison to those fed a diet without phytoestrogen additives. The most notable difference observed in the gonads was a significant down-regulation of the sex-related gene expression in the individuals fed with phytoestrogen-supplemented feed, which suggests that the studied phytoestrogens may inhibit molecular pathways responsible for sturgeon sex differentiation. Additionally, in the gonads, regardless of the studied group, the expression of foxl2 and cyp19 was observed to be female-biased, further establishing the significance of those factors during female development. In the liver, the daidzein additive was observed to have the strongest altering effect on the expression patterns of estrogen and androgen receptors which may influence estrogen- and androgen-regulatory pathways. The abovementioned findings suggested that phytoestrogens can cause significant changes in the expression profiles of sex-related genes resulting in molecular pathway alterations, which can ultimately lead to sex differentiation disturbances in sturgeons.