为提高奶牛产奶量，就要在日粮中添加高精料，这往往会引起瘤胃内环境的变化和微生物区系的改变，进而诱发一些营养代谢性障碍或疾病，如瘤胃炎、蹄叶炎、间歇性腹泻等。导致这些炎症症状主要是由于瘤胃细菌解体之后释放小肽引起的系统性炎症。识别与转运这些小肽的载体蛋白即小肽转运蛋白SLC15家族发挥着重要的作用。SLC15家族之一的PEPT1和NHE3能协同转运细菌小肽，但其转运机制尚未见报道。本项目旨在前期项目研究结果基础上，进一步利用蛋白质组学、免疫组化等分子生物学技术和生物化学技术手段阐明PEPT1和NHE3协同作用调控细菌小肽的转运和吸收途径与机制，为控制奶牛生产中的高精料日粮带来的营养障碍导致的炎症风险提供一定的理论依据。

Although high concentrate addition in the diet can improve the cow milk production, it will cause some problems, such as variations of microbiota in the rumen environment and other changes, and then induce nutrition metabolic disorder or disease, like rumen inflammation, laminitis and intermittent diarrhea. The systemic inflammation is mainly caused by the small peptide which released from rumen bacteria. The peptide-transporters SLC15 play an important role in discern and transporting the peptide. However, it is unclearly about the transport mechanism of PEPT1 and NHE3 which are members of SLC15 family. This study aims to illuminate the synergistic effects by PEPT1 and NHE3 in regulating the absorptive pathway and transport mechanism of bacterial peptide using proteomics and immunohistochemical methods. The results will helpful in controlling the risk of inflammation which caused by high concentrate addition in dairy production.