Agr/VirSR信号通路在乳酸杆菌抗肉仔鸡坏死性肠炎中的作用

产气荚膜梭菌感染造成的肉仔鸡坏死性肠炎（NE）是危害肉鸡生产的一种重要的胃肠道疾病。辅助基因调节因子（Agr）和VirS/VirR（VirSR）双因子调节系统参与了产气荚膜梭菌毒力因子的表达。我们前期研究发现，乳酸杆菌影响了感染鸡胚肠道上皮细胞的产气荚膜梭菌毒力因子表达，这是否通过调控产气荚膜梭菌的Agr/VirSR信号通路来实现，尚不清楚。本项目通过产气荚膜梭菌感染肉仔鸡建立NE模型，研究日粮中添加嗜酸乳杆菌或发酵乳杆菌对肠道产气荚膜梭菌数量和毒力因子表达的影响。采用体外培养鸡胚肠道上皮细胞的方法，研究两种乳酸杆菌对感染细胞的产气荚膜梭菌Agr/VirSR信号通路的调控作用及其机制。该项目丰富了NE的乳酸杆菌调控技术理论和实践，对肉鸡产业的健康发展具有指导意义。

Necrotic enteritis (NE) is an important poultry gastrointestinal disease caused by the overgrowth of Clostridium perfringens. In this bacterium, accessory gene regulator (Agr) and VirS/VirR (VirSR) two-component regulatory system participated in the expression of virulence factors. Our previous study showed that Lactobacillus strains affected the expression of virulence factors in C. perfringens co-cultured with the intestinal epithelial cells of chicken embryos. However, whether Lactobacillus strains achieved these effects by modulating the Agr/VirSR signaling pathway in C. perfringens is unknown. In the current study, we will build a NE model by challenging the broilers with C. perfringens and investigate the effect of dietary supplementation with L. acidophilus or L. fermentum on the number and virulence factor expression of C. perfringens in the intestine of broilers. Using in vitro isolation of primary chicken intestinal epithelial cells from chicken embyos, we will study the modulatory effect of both Lactobacillus strains on the Agr/VirRS signaling pathway of C. perfringens co-cultured with cells as well as the mechanism of this effect. This study will enlarge the theory and practice of Lactobacillus controlling techniques for NE. And, it will show practical significance for the healthy development of broiler industry.