Objective: Comparison of the effect of probiotic Bioplus 2B and antibiotic virginiamycin on immune system of broiler chicks.
Design: Completely randomized design with 4 treatments and 4 replicates for each treatment.
Animals: Four hundred male Ross chicks.
Procedure: Chicks distributed randomly into four groups. First group chicks as control group received a diet without any antibiotic and coccidiostate. Second group received diet with 0.02% virginiamycin antibiotic premix 10% and for feeding the chicks in two other groups, 0.05% and 0.1% probiotic Bioplus 2B were added to the diet;, respectively. The probiotic contained two strains of orgamsms nanely Bacillus subtilis CH 201 and Bacillus licheniformis CH200. Feed and water were provided ad- libitum throughout the expcrimental period. White blood cells (WBC) count and ratio of heterophils to lymphocytes (H/L) measured in blood samples on day 42. The chicks were inoculated with antigens Newcastel disease virus (NDV) vaccine strain lasota and injected with sheep red blood cell, and were tested for antibody production.
Statistical analysis: Statistical evaluations were based on analysis of variance, using SPSS program and comparison of means were made using Dun cans multiple rang test.
Results: The supplemention of diet with antibiotic had no significant effect on WBC count, H/L, anti SRBC antibody and anti Newcastle antibody in comparison with control. The supplemented diet with 0.l% probiotic significantly increase WBC count and decrease HIL in comparision with control (p< 0.05). However, supplemented diet with 0.05% probiotic had no significant effect on WBC count and H/L in comparision with control. Supplemention diet with different levels of probiotic Bioplus 2B had no significant effects on antiSRBC antibody and antiNeweastle antibody compared with control. Conclusion: It seems that supplementation of diet with probiotic has positive effect on hosts immune system. J. Fac. Vet. Med. Univ. Tehran. 58, 2: 159-162, 2003.