The Saccharomyces sp. and Bacillus subtilis based probiotics influence on chicken broiler productivity and caecum microbiome community

Study of probiotic microorganisms which can produce enzymes and amino acids is important to develop biologicals to prevent disease and increase productivity in poultry. Lactbacillus sp. and Bifidobacterium sp. are widely used as probiotics due to their adhesive ability and antipathogenic activity. Bacillus sp. and yeasts Saccharomyces sp. are less examined but considered perspective as probiotic agents due to antibiotic activity and some other helpful features. Using T-RFLP (Terminal Restriction Fragment Length Polymorphism) and Real-Time PCR we compared number and composition of caecum microbiome in 37-day old Cobb 500 broiler chicken. In group I the chickens were fed with balanced combined fodder. In group II the chickens were fed with the same combined fodder supplemented with a probiotic which contained Saccharomyces sp. living cells, and in group III this probiotic was replaced by a probiotic product Cellobacterin-T. Chickens' caecum microbiome contained various taxa including several unidentified phylotypes in addition to commonly found gut microorganisms. Phylum Firmcutes (mainly cellulolytic and amylolitic Clostridia ) and Bacillus sp., Lactobacillus sp., Enterococcus sp. which possess anti-bacterial activity are identified as predominating taxa. In addition, various opportunistic and pathogenic microorganism were found including causative agents of respiratory diseases ( Pasteurellaceae, Mycoplasma sp., etc.). Both probiotics resulted in an increase of total caecum microbiome and a decreased of its biodiversity. The most remarkable changes we found in the chickens fed with yeast probiotic. Caecum microbiome community of the broilers from group II showed the lowest Shannon index and Simpson index. Cellobacte-rin-T had the highest probiotic effect. In the broilers from group III the microbiome Bacillus sp. counts increased 1.38-fold, Lactobacillus sp. number was 1.47 times higher whereas the Campylobacter sp. number was 3.00 times lower and the family Enterobacteriaceae number was 1.44 times lower as compared to the control chicks. Yeast probiotic resulted in positive effect on cellulolytic Clostridia microorganisms but also led to rise of Campylobacter sp., Pasteurella sp. and Mycoplasma sp. counts. Poultry growth rate and productivity were influenced positively by both probiotics. The highest growth rate, weight gain, digestibility coefficient and vitamin A, E, B2 and carotinoid accumulation in liver were characteristic of the chickens from group III. Yeast probiotic promoted feed consumption. Chemical composition of pectoral and leg muscles of the chicks fed with probiotics remained unchanged