Effects of Macleaya Cordata Extract on LPS-Induced Intestinal Inflammation and Diarrhea via Modulation of Gut Microbiota

Diarrhea significantly impacts livestock and poultry health, causing growth delays and higher mortality rates. Macleaya cordata extract (MCE) demonstrates strong antioxidant, antibacterial, and anti-inflammatory properties, indicating its potential as a therapeutic agent for diarrhea. This research investigated whether MCE alleviates lipopolysaccharide (LPS)-induced diarrhea in mice through modulation of the gut microbiota. Here, changes in short-chain fatty acids (SCFAs) and gut bacterial structure were analyzed using gas chromatography–mass spectrometry (GC-MS) and 16S rRNA gene sequencing, respectively. The effects of MCE administration (40 mg/kg) on intestinal injury and inflammatory responses were assessed in mice induced with LPS. These results show that MCE-treated mice exhibited significantly lower diarrhea indices, attenuated duodenal villus shortening, and decreased crypt depth compared with LPS-induced mice. MCE treatment substantially reduced the mRNA expression of IL-6, IL-1β and NF-κB in the duodenum, as well as the serum levels of TNF-α and IL-8. Furthermore, MCE significantly increased SCFA levels, particularly acetic acid, and reshaped the gut microbiota composition by increasing the abundance of Lachnospiraceae. Given the close interaction between gut microbiota, microbial metabolites, and host inflammatory responses, these microbial and metabolic alterations are closely associated with the attenuation of intestinal and systemic inflammation. In conclusion, the protective effects of MCE against LPS-induced diarrhea in mice are closely associated with the modulation of gut microbiota structure, suppression of inflammatory responses, and enhancement of acetic acid production. This study provides a mechanistic basis for MCE as a natural alternative to antibiotics for treating inflammatory diarrhea in livestock and poultry.