断奶仔猪腹泻严重影响仔猪生长性能，近年研究发现其主要原因是仔猪肠道粘膜屏障不完善，在断奶过程中容易受到外来病原影响，产生氧化应激损伤。本课题组前期用大鼠作为动物模型，发现葡萄籽花青素B2作为葡萄生产的副产物，具有高效抗氧化和抑制断奶腹泻的作用。本项目拟将葡萄籽花青素B2添加到饲料中，以断乳仔猪为实验动物，观察其对仔猪腹泻的抑制作用和对生产性能的影响；通过检测花青素对屏障通透性和完整性的影响，明确其对肠道粘膜屏障的保护作用；通过微生物组学分析和代谢组学分析，揭示花青素B2对肠道微生物屏障形成的影响，特别是其对断奶仔猪肠道菌群结构、代谢产物和酶谱的影响及调节模式；最后研究其对肠道细胞内源性抗菌肽表达和抗氧化指标的调控作用和内在机制，阐明花青素B2在机体内抗氧化和粘膜屏障保护的免疫机制。为通过营养手段调控仔猪肠道微生物屏障建立，促进肠道黏膜抗氧化能力和先天免疫力，减少断乳腹泻发生提供理论依据。

Weaning diarrhea seriously influence growth performance of piglets. Accumulated studies have revealed that the intestinal barrier of the newborn piglets are not well-established, and easy to be infective, which result in oxidative stress damage of the intestinal mucosa. Our recent study using rat model indicated that grape-seed procyanidin functioned as an anti-oxidative additives, reduced the intestinal permeability and therefore inhibited weaning diarrhea. This project aims at the role of dietary grape-seed procyanidin B2 on weaning diarrhea of piglets, as well as its potential mechanism. By detection of intestinal barrier permeability and integrity, we will reveal the protection role of procyanidins B2 on intestinal mucosa. Microbial group analysis and metabolomic analysis will illuminate how procyanidin B2 modulates the process of gut microbes barrier formation, and metabolism product composition of intestinal flora in weaning piglets, as well as the role of the flora enzyme and its regulation mode. In addition, the cultural intestinal cells are treated with procyanidin B2 in vitro, which will illustrate the changed expression levels of endogenous antimicrobial peptides and oxidation index, as well as its potential mechanism. In summary, our project will reveal the role of procyanidin B2 treatment on the formation process of gut microbes barrier, which will help to imporve oxidation resistance and innate immunity of intestinal mucosa, to reduce weaning diarrhea of piglets.