A two-factor (2 × 3) orthogonal test was conducted to investigate the effects of dietary myo-inositol (MI) on the osmoregulation and carbohydrate metabolism of euryhaline fish tilapia (Oreochromis niloticus) under sustained hypertonic stress (20 practical salinity units [psu]). 6 diets containing either normal carbohydrate (NC, 30%) or high carbohydrate (HC, 45%) levels, with 3 levels (0, 400 and 1,200 mg/kg diet) of MI, respectively, were fed to 540 fish under 20 psu for 8 weeks. Dietary MI supplementation significantly improved growth performance and crude protein content of whole fish, and decreased the content of crude lipid of whole fish (P < 0.05). Curled, disordered gill lamella and cracked gill filament cartilage were observed in the gill of fish fed diets without MI supplementation. The ion transport capacity in gill was significantly improved in the 1,200 mg/kg MI supplementation groups compared with the 0 mg/kg MI groups (P < 0.05). Moreover, the contents of Na⁺, K⁺, Cl⁻ in serum were markedly reduced with the dietary MI supplementation (P < 0.05). The fish fed 1,200 mg/kg MI supplementation had the highest MI content in the gills and the lowest MI content in the serum (P < 0.05). Additionally, the fish fed with 1,200 mg/kg MI supplementation had the highest MI synthesis capacity in gills and brain (P < 0.05). Dietary MI markedly promoted the ability of carbohydrate metabolism in liver (P < 0.05). Moreover, fish in the 1,200 mg/kg MI groups had the highest antioxidant capacity (P < 0.05). This study indicated that high dietary carbohydrate would intensify stress, and impair the ability of osmoregulation in tilapia under a long-term hypersaline exposure. The supplementation of MI at 1,200 mg/kg in the high carbohydrate diet could promote carbohydrate utilization and improve the osmoregulation capacity of tilapia under long-term hypertonic stress.

采用双因素 (2 × 3) 正交试验研究了膳食肌醇(MI) 对持续高渗胁迫下广盐罗非鱼 ( Oreochromis niloticus ) 渗透压调节和碳水化合物代谢的影响 (20 个实际盐度单位 [psu ]）。将 6 种含有正常碳水化合物（NC，30%）或高碳水化合物（HC，45%）水平的饮食，分别具有 3 种水平（0、400 和 1,200 mg/kg 饮食）的 MI，在 20 psu 下喂给 540 条鱼8周。日粮添加 MI 显着提高整鱼生长性能和粗蛋白含量，降低整鱼粗脂含量 ( P < 0.05)。在未添加 MI 饲料的鱼的鳃中观察到卷曲、无序的鳃片和破裂的鳃丝软骨。与0 mg/kg MI组相比，1,200 mg/kg MI补充组鳃内离子转运能力显着提高（P  < 0.05）。^{此外，添加MI后血清中Na +}、K ⁺、Cl ^-的含量显着降低（P  < 0.05）。饲喂1200 mg/kg MI的鱼鳃中MI含量最高，血清中MI含量最低（P  < 0.05）。此外，补充 1,200 mg/kg MI 的鱼在鳃和脑中具有最高的 MI 合成能力（P  < 0.05)。膳食MI显着促进肝脏碳水化合物代谢能力( P  < 0.05)。此外，1,200 mg/kg MI组鱼的抗氧化能力最高（P  < 0.05）。这项研究表明，在长期高盐环境下，高膳食碳水化合物会加剧压力，并削弱罗非鱼的渗透压调节能力。在高碳水化合物日粮中添加 1200 mg/kg 的 MI 可以促进碳水化合物的利用，提高罗非鱼在长期高渗应激下的渗透压调节能力。