Bacillus subtilis has a beneficial effect similar to that of APC as a modulator of the inflammatory response, decreasing the expression of pro-inflammatory cytokines (IL-8, IL-18, TNF-α, and IFN-γ) and increasing that of IL-10 (an anti-inflammatory cytokine), so that it maintains a balance of the inflammatory response in bacterial infection, relevantly in chickens exposed to LPS. The gene discussed is CXCL8; the disease is bacterial infectious disease.