Abstract
In the preceding study, the induction of feminization in genetically male sterlet was achieved through the administration of a genistein (GS) dosage of 1000 µg/g feed for 180 days, commencing at 8 weeks posthatch (WPH). The present study, composed of two experiments, was conducted to investigate the effects of 8- or 16-week administration of 500 or 1000 µg GS/g feed, and 16-week administration of 1000 µg GS/g feed initiated at 8, 16, or 24 WPH. Individuals with developed oocytes in the testes were observed at both doses in the 16-week administration group, and genetic males with complete ovaries observed in the group administered 1000 µg GS/g feed. The highest number of individuals with developed oocytes in the testes was identified in the groups initiated at 8 WPH, and individuals with complete ovaries were identified in the group fed a GS feed initiated at 8 WPH. In the context of a feminization induction focused on oocyte development in the testes, a dosage of 500 µg GS/g feed, administered initiating at 8 WPH, has demonstrated a promising treatment within the experimental range. However, a 16-week feeding period with a GS-containing feed was insufficient to induce complete ovarian development in all individuals.