The gonadal development of Japanese eels (Anguilla japonica) plays a crucial role in the success of artificial breeding. Soy isoflavones, a class of phytoestrogens commonly found in aquafeeds, have shown potential in enhancing gonad development in fish. The present study evaluated the effects of dietary soy isoflavones on gonadal development, growth performance, histology, sex hormone levels, vitellogenin content, and expressi...