Vitamin E (VE) is an essential lipid-soluble vitamin that improves the fish flesh quality. However, the underlying molecular mechanisms remain unclear. This study aimed to investigate the effects of VE on growth performance and flesh quality in sub-adult grass carp (). A total of 450 fish (713.53 ± 1.50 g) were randomly divided into six treatment groups (three replicates per treatment) and fed for nine weeks with different experimental diets (dietary lipid 47.8 g/kg) that contained different levels of VE (5.44, 52.07, 96.85, 141.71, 185.66, and 230.12 mg/kg diet, supplemented as dl-α-tocopherol acetate). Notably, the treatment groups that were fed with dietary VE ranging from 52.07 to 230.12 mg/kg diet showed improvement in the percent weight gain, special growth rate, and feed efficiency of grass carp. Moreover, the treatment groups supplemented with dietary VE level of 141.71, 185.66, and 230.12 mg/kg diet showed enhancement in crude protein, lipid, and α-tocopherol contents in the muscle, and the dietary levels of VE ranging from 52.07 to 141.71 mg/kg diet improved muscle pH and shear force but reduced muscle cooking loss in grass carp. Furthermore, appropriate levels of VE (52.07 to 96.85 mg/kg diet) increased the muscle polyunsaturated fatty acid content in grass carp. Dietary VE also increased the mRNA levels of fatty acid synthesis-related genes, including , , , , , , and , and up-regulated the expression of SREBP-1 protein. However, dietary VE decreased the expression of fatty acid decomposition-related genes, including , , , and , and endoplasmic reticulum stress-related genes, including , , , , , , , and , and down-regulated the expression of p-PERK, p-IRE1, ATF6, and GRP78 proteins. In conclusion, dietary VE increased muscle fatty acid synthesis, which may be partly associated with the alleviation of endoplasmic reticulum stress, and ultimately improves fish flesh quality. Moreover, the VE requirements for sub-adult grass carp (713.53 to 1590.40 g) were estimated to be 124.9 and 122.73 mg/kg diet based on percentage weight gain and muscle shear force, respectively.

中文翻译：

---

维生素E在亚成草鱼多不饱和脂肪酸合成及缓解内质网应激中的作用

维生素E（VE）是一种必需的脂溶性维生素，可改善鱼肉品质。然而，潜在的分子机制仍不清楚。本研究旨在探讨VE对亚成草鱼生长性能和肉质的影响。总共 450 条鱼（713.53 ± 1.50 g）被随机分为 6 个处理组（每个处理 3 个重复），并用含有不同 VE 水平（5.44， 52.07、96.85、141.71、185.66 和 230.12 mg/kg 饮食，补充为 dl-α-生育酚醋酸酯）。值得注意的是，饲喂 VE 范围为 52.07 至 230.12 mg/kg 日粮的处理组显示草鱼的增重百分比、特殊生长率和饲料效率有所改善。此外，补充膳食VE水平为141.71、185.66和230.12 mg/kg饮食的治疗组显示出肌肉中粗蛋白、脂质和α-生育酚含量的增加，并且VE水平在52.07至141.71 mg/kg之间。 /kg 日粮改善了草鱼的肌肉 pH 值和剪切力，但减少了肌肉蒸煮损失。此外，适当水平的VE（52.07至96.85毫克/千克饲料）增加了草鱼肌肉多不饱和脂肪酸的含量。膳食VE还增加了脂肪酸合成相关基因的mRNA水平，包括、、、、、、和、并上调SREBP-1蛋白的表达。然而，膳食VE降低了脂肪酸分解相关基因的表达，包括、、、和，以及内质网应激相关基因，包括、、、、、、、、、和、，并下调了p-PERK的表达， p-IRE1、ATF6 和 GRP78 蛋白。总之，膳食VE增加肌肉脂肪酸合成，这可能部分与缓解内质网应激有关，并最终改善鱼肉品质。此外，根据增重百分比和肌肉剪切力，亚成年草鱼（713.53至1590.40克）的VE需求量估计分别为124.9和122.73毫克/千克日粮。