Lv Meidong, Yang Kang, Wang Xuan, Liu Chengdong, Zhou Huihui, Mai Kangsen, He Gen
Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao, China; Key laboratory of Aquaculture Nutrition (Ministry of Agriculture), Ocean University of China, Qingdao, China.
Key Laboratory of Mariculture (Ministry of Education), Ocean University of China, Qingdao, China; Key laboratory of Aquaculture Nutrition (Ministry of Agriculture), Ocean University of China, Qingdao, China.
J Nutr Biochem. 2025 Jun 24;145:110008. doi: 10.1016/j.jnutbio.2025.110008.
Glucose intolerance is prevalent in teleost fish species, making them prone to dietary carbohydrate-induced fatty liver disease. However, the underlying mechanism is not well understood. In the present study, the possible role of mTOR signaling in the regulation of glucose metabolism was examined in largemouth bass (Micropterus salmoides), an economically important carnivorous aquaculture species. An 8-wk feeding trial was conducted with largemouth bass, in which they were fed different isonitrogenous and isolipidic diets supplemented with leucine (Leu), rapamycin (Rap), or an mTOR activator (mTOR-S). The results demonstrated that mTOR stimulation significantly enhanced the growth performance and feed utilization, while mTOR inhibition had the opposite effect in largemouth bass. More importantly, mTOR stimulation significantly reduced plasma glucose levels and concomitantly increased insulin levels. Furthermore, mTOR stimulation increased glycolysis and TCA cycle activities, augmented hepatic ATP levels and suppressed AMPK phosphorylation. Accordingly, mTOR stimulation also reduced SREBP1 activity, decreased hepatic lipid content and increased glycogen content. These results demonstrated that mTOR stimulation could promote postprandial glucose utilization in largemouth bass. This could provide a new strategy for improving dietary carbohydrate tolerance in aquaculture feed formulation.
葡萄糖不耐受在硬骨鱼类中普遍存在，这使得它们容易患上由膳食碳水化合物引起的脂肪肝疾病。然而，其潜在机制尚不清楚。在本研究中，以经济上重要的肉食性水产养殖品种大口黑鲈（Micropterus salmoides）为对象，研究了mTOR信号通路在葡萄糖代谢调节中的可能作用。对大口黑鲈进行了为期8周的饲养试验，试验中给它们投喂不同的等氮和等脂日粮，并添加亮氨酸（Leu）、雷帕霉素（Rap）或mTOR激活剂（mTOR-S）。结果表明，mTOR激活显著提高了大口黑鲈的生长性能和饲料利用率，而mTOR抑制则产生相反的效果。更重要的是，mTOR激活显著降低了血浆葡萄糖水平，并同时提高了胰岛素水平。此外，mTOR激活增加了糖酵解和三羧酸循环活性，提高了肝脏ATP水平并抑制了AMPK磷酸化。因此，mTOR激活还降低了SREBP1活性，降低了肝脏脂质含量并增加了糖原含量。这些结果表明，mTOR激活可以促进大口黑鲈餐后葡萄糖的利用。这可为水产养殖饲料配方中提高对膳食碳水化合物的耐受性提供一种新策略。
