Investigation of the Immunomodulatory Effects of Combined Prebiotic, Probiotic, and Postbiotic Mixtures in Chicken Ileal Explant Cultures

Due to the rise in antimicrobial resistance, finding alternatives with beneficial effects on gut health is crucial for the poultry sector. In this field, prebiotics, probiotics, and postbiotics have emerged as promising candidates. In our study, chicken ileal explant cultures were treated with pre-, pro-, and postbiotic mixtures (PM). Each PM was obtained after 72 h of solid-state fermentation and contained Bacillus velezensis NCAIM B.001537 (BV), Bacillus subtilis NCAIM B.001538 (BS), Bacillus licheniformis NCAIM B.001539 (BL), or their combination (BC) as probiotics, their secreted metabolites (postbiotics), and wheat bran extract (prebiotic). PMs were applied at two dilutions: BV-1, BS-1, BL-1, and BC-1 denote treatment solutions with 109 CFU/mL, while BV-2, BS-2, BL-2, and BC-2 indicate 106 CFU/mL. The viability of explants was not decreased by any of the applied treatments, indicating no cytotoxic effects. Regarding immunomodulation, BV-1, BS-1, BL-1, and BC-1 increased interferon (IFN)-γ levels, while BV-1 and BS-1 increased interleukin (IL)-10 concentrations, and BC-1 enhanced IFN-α release. Furthermore, RANTES concentrations were decreased by BL-1 and BC-1 but increased by BS-2. Collectively, the PMs beneficially modulated ileal cytokine response and may be valuable immunomodulatory agents for poultry; however, further studies are warranted to explore their mechanisms of action in more detail.