EXPERIMENTAL APPROACH
The chicken colibacillosis model was established by intratracheal
instillation of APEC. The gut microbiota-depleted chicken model was
established with broad-spectrum antibiotics. Viscera index measurement
and Haematoxylin and eosin stain were applied to assess histological
changes of tissues. ELISA were used to measure the cytokines and
Quantitative-PCR were used to evaluate the gene expression. The gut
microbiota and its metabolite were detected by 16srDNA and
ultrahigh-performance liquid chromatography (LC-MS).