Figure 1.

Putative mechanisms and immune pathways modulated by probiotics in the gastrointestinal tract of chickens: (a) by inducing a robust homeostatic status through promoting tolerance and preventing inflammation; (b) by increasing the luminal defence capacity of the host against pathogens. CpG oligodeoxyunucleotide sequences (CpG-ODN); nuclear factor-kappa B (NF-κB); toll-like receptor (TLR); short-chain fatty acid (SCFA); interleukin (IL); dendritic cell (DC); natural killer (NK); C-reactive protein (CRP); mannose-binding lectin (MBL); serum amyloid A (SAA); α1-acid glycoprotein (α1AGP); secretory immunoglobulin A (sIgA); host defence peptide (HDP); and goblet cell (GC). Figure created with BioRender.