Insights into the roles of vitamin D3 on the antioxidant capacity, flesh quality, and myofiber development of giant freshwater prawns (Macrobrachium rosenbergii)

Vitamin D3 (VD 3 ) is crucial for the growth and physiological functions of aquatic species, yet its effects on crustaceans, particularly regarding flesh quality, and myofiber development, remain poorly understood. This study investigated the impact of dietary VD 3 supplementation on growth performance, antioxidant capacity, flesh quality, and myofiber development in the giant freshwater prawn ( Macrobrachium rosenbergii ). Six experimental diets containing varying VD 3 levels (0.10, 0.18, 0.28, 0.48, 0.68, and 0.88 mg/kg) were formulated and fed to juvenile prawns for 70 d. Optimal VD 3 supplementation at 0.48 mg/kg significantly improved growth performance, feed utilization, and muscle nutrient composition, including increased crude protein and lipid content ( P < 0.05). VD 3 remarkably increased the levels of Gln, Tau, C18:0, C18:1n9c, C18:2n6c, and C20:5n3 in the muscle ( P < 0.05). Flesh quality analysis showed that VD 3 reduced cooking loss and lactic acid contents while enhancing the body color, shear force, hardness, chewiness, collagen contents, suggesting the enhanced flesh quality. Antioxidant capacity was enhanced by VD 3 , as evidenced by reduced reactive oxygen species and malondialdehyde levels, alongside increased antioxidant enzyme activities ( P < 0.05). Additionally, VD 3 promoted myofiber development by increasing the proportion of small-diameter myofibers (< 20 μm) and myofiber density, and decreasing the large-diameter myofibers (> 50 μm), which correlated with improved muscle hardness and texture. Molecular analysis revealed that VD 3 upregulated key genes involved in cell proliferation and differentiation, protein synthesis, and decreased the protein degradation gene expression, indicating its role in modulating muscle growth through the target of rapamycin and forkhead box protein 1 signaling pathways. Quadratic regression analysis determined the optimal dietary VD 3 requirements for M. rosenbergii to be 0.50 mg/kg for growth and 0.55 mg/kg for muscle protein content. These findings highlight VD 3 as a promising nutritional intervention to enhance the quality of aquatic meat products. • VD supplementation at 0.48 mg/kg boosted growth, feed utilization, and flesh quality in prawns. • Enhanced antioxidant capacity and reduced oxidative stress in prawn muscle were observed with VD. • VD improved flesh quality and myofiber growth via TOR and FoxO1 signaling. • VD intervention is vital to ensure sustainable high-quality aquaculture production.