Antiviral effect of lactoferrin against infectious bronchitis virus (IBV) are associated with alterations in the gastrointestinal microbiome

T cells in the ileum were reduced by LF, whereas the mRNA expression levels of IFN-γ, IL-2, and IL-4 were upregulated by LF. Moreover, the IBV-induced downregulation of MUC2, occludin, and ZO-1 in the ileum was reversed by LF. LF shifted the ileal microbiota toward homeostasis, regulated the immune response to facilitate viral clearance, and restored the intestinal barrier damaged by IBV TW-I and TW-II infection.