Effect of dietary supplementation of Bacillus subtilis, Lactobacillus plantarum and mannan oligosaccharides on immune response in broiler chicken

A study was conducted to study the influence of dietary supplementation with Lactobacillus plantarum, Bacillus subtilis, mannan-oligosaccharides (MOS) and their combinations on intestinal immune response in broiler chicken. A total of 216-day-old Cobb broiler chicks were assigned to six treatment groups with each group comprising three replicates of 12 birds each, ensuring a completely randomised design (CRD): T1 (control), T2 (L. plantarum), T3 (B. subtilis), T4 (MOS), T5 (L. plantarum MOS) and T6 (B. subtilis MOS). The humoral immune response was assessed by measuring antibody titres against the Newcastle disease vaccine using the haemagglutination inhibition (HI) test at 7, 14, 21, 28, and 35 days of age. Significant differences in antibody titres were observed only on the 28th day, with the group receiving B. subtilis and MOS (T6) exhibiting the highest titre. The results suggest that B. subtilis, particularly in combination with MOS, enhanced the vaccine-induced immune response at specific time points. The cell-mediated immune response was evaluated through cutaneous hypersensitivity reactions to 2,4-dinitrochlorobenzene (DNCB) at 24, 48 and 72 hours post-injection, though numerical differences were noted, particularly in the T6 group at 48 hours, the variations were not statistically significant. The findings highlighted that dietary supplementation with probiotics and prebiotics had enhanced immune responses during specific periods but with consistent results. Future research may focus on optimising supplementation strategies and exploring mechanisms to maximize the immunomodulatory potential of probiotics and prebiotics in broilers.