L‐Theanine alleviates heat stress through modulation of gut microbiota and immunity

作者：Sha Liu, Bin Wang, Ling Lin, Wei Xu, Zhihua Gong, Wenjun Xiao · 发表于：Journal of the Science of Food and Agriculture · 年份：2023 · DOI：10.1002/jsfa.13095 · 被引用次数：18 · 研究领域：Gut microbiota and health、Tea Polyphenols and Effects、Bee Products Chemical Analysis

Abstract BACKGROUND Heat stress (HS) damages the intestines, disrupting gut microbiota and immune balance. l ‐Theanine (LTA), found in tea, alleviates oxidative stress and cell apoptosis under HS; however, its effects on gut microbiota and immunity under HS remain unclear. To investigate this, we administered LTA doses of 100, 200, and 400 mg·kg −1 ·d −1 to C57BL/6J mice. On day 44, the model group and LTA intervention group were subjected to continuous 7‐day HS treatment for 2 h per day. RESULTS The results demonstrated that LTA intervention improved food intake, body weight, and intestinal epithelium, and reduced the water intake of heat‐stressed mice. It increased the abundance of Turicibacter , Faecalibaculum , Bifidobacterium , and norank_f_Muribaculaceae , while reducing that of Lachnoclostridium and Desulfovibrio . LTA intervention also increased the concentrations of amino acid and lipid metabolites, regulated macrophage differentiation stimulated by gut microbiota and metabolites, reduced the antigen presentation by macrophages to the specific immune system, promoted B‐cell differentiation and sIgA secretion, inhibited pro‐inflammatory factors, and enhanced intestinal defense. Mechanistically, LTA downregulated heat shock protein 70 expression and the TLR4/NF‐ κ B/p38 MAPK signaling pathway, restoring gut microbiota and immune balance. CONCLUSION We suggest that LTA can alleviate HS by modulating gut microbiota, metabolites, and immunity, indicating its potential as ...