AbstractŠabatková J., I. kumprecht, P. Zobač, P. Suchý, B. Čermák: The Probiotic BioPlus 2B as an Alternative to Antibiotics in Diets for Broiler Chickens. Acta Vet. Brno 2008, 77: 569-574.The main aim of this work was to compare the stimulatory effect of the probiotic BioPlus 2B with that of the antibiotic Avilamycin on the growth and feed conversion in broiler chickens. The growth experiment was performed with one-day-old sexed female and male rOSS 308 hybrid chickens (240 females and 240 males) placed in 24 cages. They were fed the starter diet from Day 1 to Day 14, followed by the grower from Day 15 to Day 35 and the finisher in a loose form from Day 36 to Day 42. Diets and water were available ad libitum. The control slaughter of chickens was performed at the end of the experiment (Day 42) to determine the slaughter yield and the content of inner fat in the final product. The supplementation of the diets used in broiler prefattening and fattening with BioPlus 2B resulted in a 4-5% weight gain (P < 0.01) and in a 4-5% improvement (P < 0.01) in feed conversion. Mean slaughter yields were higher (P < 0.01) in chickens fed diets containing probiotic and antibiotic products compared to the group of chickens fed the diet not supplemented with a growth promotor. The weight of inner fat in chickens under study did not differ significantly either between experimental groups or between sexes.