Optimizing gonadal development and muscle flavor quality in the male Chinese mitten crabs (Eriocheir sinensis): Utilization of soy isoflavones in crustaceans.

Nutritional regulation is the key strategy for improving aquatic products quality. This research evaluated the impacts of soy isoflavones on gonadal development and muscle quality in male Chinese mitten crabs (Eriocheir sinensis). Crabs were fed diets containing soy isoflavones (0, 33.14, 71.36, or 373.26 mg/kg) for 12 weeks. Results revealed that soy isoflavones may regulate gonadal development through "eyestalk-accessory gonad-testis" endocrine axis. Moreover, they promoted protein deposition in muscles and enriched highly unsaturated fatty acids (HUFAs) and total polyunsaturated fatty acids (PUFAs). In addition, soy isoflavones increased the muscle fibers density while reducing diameter, and significantly increased the umami amino acids proportion and equivalent umami concentration (EUC). This research shows that soy isoflavones can effectively enhance the gonadal development, nutritional value, flavor characteristics, and health benefits of aquatic foods, with a recommended supplementation amount of 71.36 mg/kg in crab feed.