Sui Zhongmin, Wang Ning, Zhang Xiaojing, Liu Chengdong, Wang Xuan, Zhou Huihui, Mai Kangsen, He Gen
Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao, 266003, China; Key Laboratory of Aquaculture Nutrition and Feeds, Ministry of Agriculture, Ocean University of China, Qingdao, 266003, China.
Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao, 266003, China; Key Laboratory of Aquaculture Nutrition and Feeds, Ministry of Agriculture, Ocean University of China, Qingdao, 266003, China.
Fish Shellfish Immunol. 2023 Oct;141:109060. doi: 10.1016/j.fsi.2023.109060. Epub 2023 Sep 9.
Intestinal damage and inflammation are major health and welfare issues in aquaculture. Considerable efforts have been devoted to enhancing intestinal health, with a specific emphasis on dietary additives. Branch chain amino acids, particularly leucine, have been reported to enhance growth performance in various studies. However, few studies have focused on the effect of leucine on the intestinal function and its underlying molecular mechanism is far from fully illuminated. In the present study, we comprehensively evaluated the effect of dietary leucine supplementation on intestinal physiology, signaling transduction and microbiota in fish. Juvenile turbot (Scophthalmus maximus L.) (10.13 ± 0.01g) were fed with control diet (Con diet) and leucine supplementation diet (Leu diet) for 10 weeks. The findings revealed significant improvements in intestinal morphology and function in the turbot fed with Leu diet. Leucine supplementation also resulted in a significant increase in mRNA expression levels of mucosal barrier genes, indicating enhanced intestinal integrity. The transcriptional levels of pro-inflammatory factors il-1β, tnf-α and irf-1 was decreased in response to leucine supplementation. Conversely, the level of anti-inflammatory factors tgf-β, il-10 and nf-κb were up-regulated by leucine supplementation. Dietary leucine supplementation led to an increase in intestinal complement (C3 and C4) and immunoglobulin M (IgM) levels, along with elevated antioxidant activity. Moreover, dietary leucine supplementation significantly enhanced the postprandial phosphorylation level of the target of rapamycin (TOR) signaling pathway in the intestine. Finally, intestinal bacterial richness and diversity were modified and intestinal bacterial composition was re-shaped by leucine supplementation. Overall, these results provide new insights into the beneficial role of leucine supplementation in promoting intestinal health in turbot, offering potential implications for the use of leucine as a nutritional supplement in aquaculture practices.
肠道损伤和炎症是水产养殖中的主要健康和福利问题。人们已经付出了相当大的努力来促进肠道健康，特别强调了膳食添加剂。在各种研究中，支链氨基酸，尤其是亮氨酸，已被报道能提高生长性能。然而，很少有研究关注亮氨酸对肠道功能的影响，其潜在的分子机制也远未完全阐明。在本研究中，我们全面评估了日粮中添加亮氨酸对鱼类肠道生理、信号转导和微生物群的影响。将幼体大菱鲆（Scophthalmus maximus L.）（10.13±0.01g）分别投喂对照日粮（Con日粮）和添加亮氨酸的日粮（Leu日粮）10周。研究结果显示，投喂Leu日粮的大菱鲆肠道形态和功能有显著改善。添加亮氨酸还导致黏膜屏障基因的mRNA表达水平显著增加，表明肠道完整性增强。补充亮氨酸后，促炎因子il-1β、tnf-α和irf-1的转录水平降低。相反，补充亮氨酸上调了抗炎因子tgf-β、il-10和nf-κb的水平。日粮中添加亮氨酸导致肠道补体（C3和C4）和免疫球蛋白M（IgM）水平升高，同时抗氧化活性增强。此外，日粮中添加亮氨酸显著提高了肠道中雷帕霉素靶蛋白（TOR）信号通路的餐后磷酸化水平。最后，亮氨酸补充改变了肠道细菌的丰富度和多样性，并重塑了肠道细菌组成。总体而言，这些结果为亮氨酸补充在促进大菱鲆肠道健康中的有益作用提供了新的见解，为亮氨酸作为水产养殖实践中的营养补充剂的应用提供了潜在的启示。
