Effects of dietary soy isoflavones on nutritional value and edible quality in female Chinese mitten crabs (Eriocheir sinensis)

Nutritional regulation strategies contribute significantly to optimize the quality of aquatic products. In this study, the potential of dietary soy isoflavones (SIF) at different levels (0, 32.51, 70.83, and 369.03 mg/kg) to improve the nutritional value and edible quality of female Chinese mitten crabs (Eriocheir sinensis) was evaluated through an 11-week feeding trial. The results demonstrated that 32.51–70.83 mg/kg SIF significantly increased the total edible yield and condition factor. It also promoted protein and lipid deposition in the ovary and muscle. Additionally, SIF improved the fatty acid composition, particularly the LC-PUFA profile. Concomitant improvements in tissue coloration and muscle textural properties were also observed. Moreover, flavor-related free amino acids were significantly enriched in muscle, collectively contributing to improved edible quality. In contrast, 369.03 mg/kg dietary supplementation enhanced coloration in certain tissues and muscle hardness. However, it had adverse effects on lipid accumulation in the hepatopancreas and the textural properties of leg muscle. Therefore, dietary supplementation with 32.51–70.83 mg/kg SIF promoted better nutritional value and flavor quality of E. sinensis.