断奶仔猪微生物肠型及postbiotics介导群体感应的日粮调控

断奶腹泻是养猪业世界性难题，而不同猪种断奶腹泻率有很大差异。肠道微生物是影响仔猪肠道健康的重要因素，为阐明其在不同猪种断奶阶段肠道发育的作用机理，本项目将“肠型”和postbiotics介导群体感应的理论引入断奶仔猪肠道的生物学基础研究。基于我国部分地方猪种断奶腹泻率低等特征，以仔猪肠道黏膜发育和免疫功能为基础，从体内和体外两方面，比较地方猪和三元杂交猪肠道菌群结构模式并划分肠型；分离鉴定乳酸杆菌、双歧杆菌、枯草芽孢杆菌等肠型形成的特征菌，阐明其通过特异性postbiotics介导群体感应系统，调控生物膜形成，抑制病原菌粘附定植的机理，并通过菌群移植和表型重现进行功能验证。在此基础上，筛选鉴定靶向调控肠道关键菌群和postbiotics表达的营养素，揭示其营养调控模式，阐明肠道菌群与黏膜天然免疫系统的协同效应机理。项目进展将为通过营养干预调节仔猪肠道群体感应，改善断奶腹泻提供新的理论依据。

Weaning diarrhea is a worldwide problem in the pig industry. Different pig breeds have different diarrhea rates. Considering the importance and complexity of piglet intestinal microbiota that contributes a lot to its health and well-being, the useful approach of population stratification, termed “enterotypes” and quorum sensing induced by postbiotics are introduced into the fundamental research of the intestine of weaned piglets in this project. Based on the characteristic of low diarrhea in native Chinese breeds, enterotypes of weaned piglets are divided in vivo and in vitro, based on the intestinal mucosal development and immune function of piglets. Differential bacteria such as Lactobacillus, Bifidobacterium, and Bacillus subtilis are isolated and identified, which consist of the highest proportion of enterotype formation. Postbiotics generated from these bacteria are capable of triggering the quorum sensing system, generating bacterial biofilm, and inhibiting pathogen adhesion, which specific mechanism will be clarified in this project. In addition, phenotypic reproduction through fecal microbiota transplantation (FMT) is applied for functional verification of microbes. On this basis, nutrients that target postbiotics in key intestinal micorbiota are screened and identified, exploring its nutritional intervention model and revealing the synergistic effect between intestinal microbes and mucosal natural immune system. Carryout of this project will target quorum sensing and provide theoretical basis for relieving diarrhea in weaned piglets through nutritional interventions.