Gut microbiota of broiler chickens influenced by probiotics and antibiotics as revealed by T-RFLP and RT-PCR

In poultry, and birds in general, the gut is not only the first line of the defense from exogenous pathogens, but also the biggest immunity organ. The microflora inhabiting blind gut plays multifunctional role in the maintenance of homeostasis in macroorganism, being involved in different processes including fodder digestion. Probiotic, antibiotic, prebiotic, symbiotic preparations, enzymes, etc., affecting directly or ndirectly the gut microflora, can thus increase daily weigh growth and viability in chickens, and the slaughter yield. They also improve a digestibility of fodder nutrients, quality and sanitary condition of the birds. However, the influence of these agents on gut microflora in chickens is still not cleared up. Recent molecular approaches allow studying microbial biodiversity without traditional limitations we are faced with when applying microbiological techniques. By T-RFLP and RT-PCR, the composition and growth dynamics of gut microflora were examined in the Cobb 500 broiler chickens fed with probiotic Cellobacterin-T and antibiotic Stafak-110 as feed additives to the complete diet. By these methods, the probiotic and antibiotic additives were shown to contribute to the development of microbiota. In particular they increased the total number of bacteria, what is more, the normal gastrointestinal flora, i.e. cellulolytic bacteria, lactobacilli, bifidobacteria, bacilli, selenomonas species, increased, while the unwanted enterobateria and actinimycetes decreased. In case we used the probiotics in poultry diet when compared to antibiotics, in the studied parts of the intestinal of broiler chickens there were more cellulolytic bacteria, and in the blind gut the number of lactobacilli, bifidobacteria and bacilli was 10-100 times higher, while clostridia and transit bacteria number decreased. Numerous investigations affirmed the effectiveness of probiotics in poultry basing on zootechnical parameters, however, only molecular identification of the gut microbiota members by means of T-RFLP-PCR and RT-PCR analysis allows detecting and attributing their taxonomic groups influenced by a specific feed additive for further justification of its rational use.