Sun Xiao, Cui Yalei, Su Yingying, Gao Zimin, Diao Xinying, Li Ju, Zhu Xiaoyan, Li Defeng, Li Zhentian, Wang Chengzhang, Shi Yinghua
College of Animal Science and Technology, Henan Agricultural University, Zhengzhou, China.
Henan Key Laboratory of Innovation and Utilization of Grassland Resources, Zhengzhou, China.
mSystems. 2021 Apr 6;6(2):e01374-20. doi: 10.1128/mSystems.01374-20.
Weaning of piglets is accompanied by intestinal inflammation, impaired intestinal barrier function, and intestinal microflora disorder. Regulating intestinal microflora structure can directly or indirectly affect intestinal health and host growth and development. However, whether dietary fiber (DF) affects the inflammatory response and barrier function by affecting the intestinal microflora and its metabolites is unclear. In this study, we investigated the role of intestinal microflora in relieving immune stress and maintaining homeostasis using piglets with lipopolysaccharide (LPS)-induced intestinal injury as a model. DF improved intestinal morphology and barrier function, inhibited the expression of inflammatory signal pathways (Toll-like receptor 2 [TLR2], TLR4, and NF-κB) and proinflammatory cytokines (interleukin 1β [IL-1β], IL-6, and tumor necrosis factor alpha [TNF-α]), and upregulated the expression of barrier-related genes (encoding claudin-1, occludin, and ZO-1). The contents of proinflammatory cytokines (IL-1β, IL-6, and TNF-α) and the activity of diamine oxidase in plasma were decreased. Meanwhile, DF had a strong effect on the composition and function of intestinal microflora at different taxonomic levels, the relative abundances of cellulolytic bacteria and anti-inflammatory bacteria were increased, and the concentrations of propionate, butyrate, and total short-chain fatty acids (SCFAs) in intestinal contents were increased. In addition, the correlation analysis also revealed the potential relationship between metabolites and certain intestinal microflora, as well as the relationship between metabolites and intestinal morphology, intestinal gene expression, and plasma cytokine levels. These results indicate that DF improves intestinal barrier function, in part, by altering intestinal microbiota composition and increasing the synthesis of SCFAs, which subsequently alleviate local and systemic inflammation. Adding DF to the diet of LPS-challenged piglets alleviated intestinal and systemic inflammation, improved intestinal barrier function, and ultimately alleviated the growth retardation of piglets. In addition, the addition of DF significantly increased the relative abundance of SCFA-producing bacteria and the production of SCFAs. We believe that the improvement of growth performance of piglets with LPS-induced injury can be attributed to the beneficial effects of DF on intestinal microflora and SCFAs, which reduced the inflammatory response in piglets, improving intestinal barrier function and enhancing body health. These research results provide a theoretical basis and guidance for the use of specific fiber sources in the diet to improve intestinal health and growth performance of piglets and thus alleviate weaning stress. Our data also provide insights for studying the role of DF in regulating gastrointestinal function in human infants.
仔猪断奶伴随着肠道炎症、肠道屏障功能受损和肠道微生物群紊乱。调节肠道微生物群结构可直接或间接影响肠道健康以及宿主的生长发育。然而，膳食纤维（DF）是否通过影响肠道微生物群及其代谢产物来影响炎症反应和屏障功能尚不清楚。在本研究中，我们以脂多糖（LPS）诱导肠道损伤的仔猪为模型，研究肠道微生物群在缓解免疫应激和维持体内平衡中的作用。DF改善了肠道形态和屏障功能，抑制了炎症信号通路（Toll样受体2 [TLR2]、TLR4和核因子κB [NF-κB]）和促炎细胞因子（白细胞介素1β [IL-1β]、IL-6和肿瘤坏死因子α [TNF-α]）的表达，并上调了屏障相关基因（编码闭合蛋白-1、闭锁蛋白和紧密连接蛋白-1）的表达。血浆中促炎细胞因子（IL-1β、IL-6和TNF-α）的含量以及二胺氧化酶的活性降低。同时，DF在不同分类水平上对肠道微生物群的组成和功能有显著影响，纤维素分解菌和抗炎菌的相对丰度增加，肠道内容物中丙酸、丁酸和总短链脂肪酸（SCFA）的浓度升高。此外，相关性分析还揭示了代谢产物与某些肠道微生物群之间的潜在关系，以及代谢产物与肠道形态、肠道基因表达和血浆细胞因子水平之间的关系。这些结果表明，DF部分通过改变肠道微生物群组成和增加SCFA的合成来改善肠道屏障功能，进而减轻局部和全身炎症。在LPS攻击的仔猪日粮中添加DF可减轻肠道和全身炎症，改善肠道屏障功能，并最终缓解仔猪的生长迟缓。此外，添加DF显著增加了产生SCFA的细菌的相对丰度和SCFA的产生。我们认为，LPS诱导损伤的仔猪生长性能的改善可归因于DF对肠道微生物群和SCFA的有益作用，这降低了仔猪的炎症反应，改善了肠道屏障功能并增强了身体健康。这些研究结果为在日粮中使用特定纤维来源改善仔猪肠道健康和生长性能从而减轻断奶应激提供了理论依据和指导。我们的数据也为研究DF在调节人类婴儿胃肠功能中的作用提供了见解。
