Optimizing Low Fishmeal Diets with Vitamin C Supplementation: A Comprehensive Study on Growth, Immunity, and Heat Stress Resistance in Largemouth Bass (Micropterus salmoides) Juveniles

作者：Shen Zhao, Hualiang Liang, Xiaoru Chen, Lu Zhang, Dongyu Huang, Yongli Wang, Zhenyan Cheng, Mingchun Ren · 发表于：Antioxidants · 年份：2025 · DOI：10.3390/antiox14101175 · 被引用次数：2 · 研究领域：Aquaculture Nutrition and Growth、Moringa oleifera research and applications、Antioxidant Activity and Oxidative Stress

Six dietary groups were supplemented with graded vitamin C (VC) levels: VC1 (control, 0.39 g/kg), VC2 (0.51 g/kg), VC3 (0.66 g/kg), VC4 (0.81 g/kg), VC5 (0.97 g/kg), and VC6 (1.11 g/kg). Largemouth bass (Micropterus salmoides) with an initial weight of 2.21 ± 0.00 g were fed these diets for 8 weeks to evaluate the effects of different VC levels on growth performance, immune response, and heat stress resistance. Heat stress was induced at a constant temperature of 33.00 ± 0.16 °C for one week. The VC3 and VC4 groups showed significantly improved growth performance (FBW, WGR, SGR) compared to VC1 (p < 0.05). VC4 exhibited lower ALT and AST levels before and after heat stress. Antioxidant capacity (T-AOC, GSH-Px, CAT) was significantly enhanced in VC3–VC5, with VC5 showing the highest after stress activity (except CAT). Expression of pro-inflammatory genes (nf-κb, il-8) was downregulated in VC4 and VC5, while anti-inflammatory il-10 was upregulated in VC4 after stress. Apoptosis-related genes (bcl-2, caspase, bax) and TUNEL assays indicated the strongest anti-apoptotic effects in VC3 and VC4 under heat stress (p < 0.05). These findings suggest that VC supplementation in low-fishmeal diets enhances growth, immune response, apoptosis resistance, and acute heat stress tolerance in fish.