Induction of gonadal feminization in farmed sterlet Acipenser ruthenus upon oral genistein administration

Abstract Caviar, a delicacy prepared from sturgeon ovaries, is notoriously expensive. Recent advances have enabled the production of caviar from sturgeons. This study aimed to enhance the production efficiency of female monosex cultures using genistein, an isoflavone with estrogenic effects that is abundant in soybeans. Twenty-five sterlets ( Acipenser ruthenus ) aged 56 days post-hatch (DPH) were administered one of three feeds containing genistein (GS) for 180 days: GS10 (10 μg GS/g diet), GS100 (100 μg GS/g diet), or GS1000 (1000 μg GS/g diet). A positive control group was fed a diet containing 10 μg 17β-estradiol (E2)/g diet. Following treatment, the fish were reared on commercial feed, and seven to nine sterlets from each group were sampled at 311–312 DPH. A negative control group of ten sterlets raised on a standard diet was sampled. Gonadal morphology was histologically analyzed, the long axis of oocytes calculated, and genetic sex was determined using PCR methodology to assess the effects of genistein administration. The gonads of all genetic females from all of the groups developed into ovarian tissues. In the negative control, GS10, and GS100 groups, genetic male gonads developed into testes. In contrast, genotypic sterlets in the E2 and GS1000 groups developed ovarian tissue, indicating successful feminization via oral genistein administration.