An experiment was conducted on 198 one-day-old broiler chicks to evaluate the influence of supplementation of probiotic (PRO), prebiotic (PRE) and synbiotic (SYN) for 42 days as alternatives to antibiotics on performance, immunity and histopathological examination of immune organs. Our study revealed that the body weight (BW), the weight gain (WG) and the feed convertion ratio (FCR) in the biotic products supplemented birds did not show significant differences from the control group, also there were no significant changes in the mortality rate. On the other hand, we recorded a significant improvement of these parameters in the antibiotic (AB) treated group in comparison with the control group. The T lymphocyte activity against infectious bursal disease (IBD) vaccination in the birds supplemented with the biotic products was improved at day (d) 14 post vaccination in comparison with both the antibiotic and the control groups. The humoral immune response against Newcastle disease (ND) vaccination in the PRO and PRE supplemented birds was significantly improved at d 42 of age in comparison with the vaccinated non treated control group. The PRE significantly improved the weight of BF at d 42. The SYN and PRE treatments caused increase in the villar length of the small intestine in comparison with the control group.