Effect of different feeding modes on the growth, biochemical composition, and living environment of the juvenile Chinese mitten crab Eriocheir sinensis

Enhancing the production and quality of juvenile Chinese mitten crab Eriocheir sinensis, while also ensuring environmental sustainability, are becoming increasingly important for both producers and consumers. In this study, the effects of three feeding modes (traditional, formulated, and mixed) on the growth and biochemical composition of juvenile E. sinensis and their living environment were compared. At the end of culture, the terminal mass, weight gain rate and specific growth gain rate of juvenile E. sinensis were the highest in the formulated group (P < 0.05). The crude protein, total lipids, and ash content of the hepatopancreas were not significantly different under the three groups (P > 0.05), and only the ash content of the body in the traditional group was lowest (P < 0.05). The C22:6n3 and ΣHUFA content, and DHA/EPA radio of the hepatopancreas were highest in the formulated group (P < 0.05), but the content of most fatty acids in the body were not significantly different under the three groups (P > 0.05). The ΣEAA, ΣNEAA and TAA content of the body were highest in the mixed group (P < 0.05). Under the three feeding modes, the NH₄⁺, NO₃⁻ and TN content in the water negatively accumulated, whereas the NO₂⁻ and TP content positively accumulated, with TP of the formulated group having the lowest cumulation (P < 0.05). C accumulated in the sediment were lowest in the formulated group, and N in the mixed group, while P negatively accumulated in the formulated group (P < 0.05). Overall, formulated pellet feed in this study promoted the rapid growth and nutrient accumulation of juvenile crabs. However, the mixed feeding mode enhanced more balanced amino acid ratio in juvenile crabs. Additionally, the formulated feeding mode caused the least pollution to the living environment of juvenile E. sinensis. Collectively, our findings demonstrate that the formulated feeding mode is most conducive for sustainable development of the crab aquaculture industry.