仔猪缺铁症是仔猪的易发病，给仔猪补铁已成为普遍使用的常规手段。然而，在仔猪腹泻情况下补铁反而加重感染，其原因是补充的铁促进了病原微生物的生长繁殖。因此，如何在感染情况下对仔猪进行科学补铁就成为生猪健康养殖的关键。基于脂质运载蛋白2（Lcn2）既能结合细菌铁载体抑制细菌获铁，又可替代转铁蛋白发挥铁运输作用，本项目拟在系统阐述仔猪Lcn2表达与机体铁代谢、抗感染免疫关系的基础上，通过构建仔猪细菌感染模型，聚焦仔猪肠道功能，探讨Lcn2对肠道铁吸收、菌群结构和固有屏障功能的影响；利用体外细胞模型，探究Lcn2对猪小肠上皮细胞炎症损伤和巨噬细胞铁代谢及极化的调控；进一步利用敲除鼠模型，深入分析Lcn2影响肠道抗感染免疫的途径及分子机制。通过本项目的研究，将揭示Lcn2在仔猪肠道免疫与病原菌互作中的重要功能，为感染情况下仔猪缺铁症的预防和控制提供新思路。

Iron deficiency in piglets is a susceptible nutritional deficiency disease. Iron supplementation has been proved to be beneficial and used widely in pig breeding. However, it doesn’t work for piglets under diarrhea or infection stress, because iron is an essential nutrient for both animals and pathogens. Therefore, how to supply iron scientifically becomes a key to healthy breeding pigs. Lipocalin-2 (Lcn2) can not only prevent bacterial iron acquisition by sequestering iron-loaded siderophores, but also transport iron instead of transferrin. The project will take piglets as mode animals to figure out the relationship among Lcn2 expression, iron homeostasis and innate immune defense. Researches will tackle the challenging questions how Lcn2 affect the interaction between gut immunity and iron-withholding defenses to response to bacterial infection, ensuring that host-pathogen interface remains an ever-evolving battleground for iron. Through this project, we will reveal the important functions of Lcn2 in regulating gut immunity of piglets, and provide new ideas for the prevention of iron deficiency in piglets under infection.