Evaluation of bacillus subtilis spores probiotic as an alternative to amoxicillin as a growth promoter to protect broiler chickens against pathogenic E.coli and clostridium perfringens / Dina Abo Elsoud Abdo Elsaid ; Supervised Ahmed Samir Mohamed , Ahmed M. Galal Soliman , Heba Mohamed M. Salem

Thesis (M.Sc.) - Cairo University - Faculty of Veterinary Medicine - Department of Microbiology

This study was conducted to evaluate the efficacy of Bacillus subtilisspores probiotic as an alternative to antibiotic growth promoter by monitoring its effect on broiler chickens performance and determination of the intestinal bacterial count. Three experimental trials were conducted on 480 broiler chickens, 160 birds per each one, four treatments (40 birds) with four replicates (10 broilers per pen). In the first experimental trial; T1: control group (supplemented with basal diet) was compared against T2: supplemented with basal diet + amoxicillin 50% as an antibiotic growth promoter, T3: supplemented with basal diet + Bacillus subtilisspores probiotic and T4: supplemented with basal diet + both antibiotic and probiotic together. An improvement was recorded in feed conversion ratio (FCR) on 42-days-old broiler chickens supplemented with Bacillus subtilisspores probiotic (T3) when compared with the other groups. Reduction in E.coli count in T2 and T3 was observed. Notable reduction in clostridium perfringens count in T3 compared to others. Treatments of the second and third experiment were: T1: unmedicated, unchallenged group: control, T2: unmedicated, challenged group, T3: medicated with amoxicillin 50%, challenged group, T4: medicated with Bacillus subtillis spores probiotic, challenged group, challenge was done with E.coli and Clostridium perfringens in the second and third experiment respectively. The results demonstrated a reduction in E.coli and Clostridium perfringens count in treatment supplemented with Bacillus subtilis spores probiotic (T4) and also show a better FCR in both experiments. The current study concluded that the Bacillus subtilisspores probiotic could replace antibiotic growth promoter under investigation with better FCR and lower intestinal bacterial pathogens count

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