Chemical composition and protective effect of guava (Psidium guajavaL.) leaf extract on piglet intestines

Abstract BACKGROUND Dietary intervention is an important approach to improve intestinal function of weaned piglets. Phytogenic and herbal products have received increasing attention as in‐feed antibiotic alternatives. This study investigated the chemical composition of guava leaf extract (GE) by ultrahigh‐performance liquid chromatography–tandem mass spectrometry (UPLC‐MS/MS). Meanwhile, we investigated the effects of dietary supplementation with GE on diarrhea in relation to immune responses and intestinal health in weaned piglets challenged by enterotoxigenic Escherichia coli (ETEC). RESULTS In total, 323 characterized compounds, which including 91 phenolic compounds and 232 other compounds were identified. Animal experiment results showed that the supplementation of 50–200 mg kg −1 of GE in the diet could reduce diarrhea incidence, increase activities of superoxide dismutase, glutathione peroxidase and total anti‐oxidant capacity in the serum ( P < 0.05), decrease the levels of interleukin 1β, interleukin 6 and tumor necrosis factor α in the serum or jejunum mucosa ( P < 0.05), and increase villus height and villus height to crypt depth ratio ( P < 0.05) in the jejuna of piglets challenged by oral ETEC compared with negative control group (NC). Meanwhile, diet supplementation with 50–200 mg kg −1 GE reduced the levels of D‐lactate, endothelin‐1 and diamine oxidase in the serum, and increased the expression of zonula occludens‐1, Claudin‐1, Occludin and Na + /H + exchanger 3 ( P < 0.05) in the jejuna mucosa of piglets challenged by ETEC compared with the NC. CONCLUSIONS These results suggested that GE could attenuate diarrhea and improve intestinal barrier function of piglets challenged by ETEC. © 2020 Society of Chemical Industry