Influence of Additional Level of Probiotics on Intestinal Microbiota in Broiler Chickens

The digestive tract of broiler chickens contains a highly complex microbiota, generally consisting of body beneficial bacteria and, in some cases, of pathogen bacteria. To reduce the quantity of pathogen bacteria, the structure of this microbiota can be changed by using some feed additives, such as probiotics. The purpose of the experiment was to establish the influence of the additional level of probiotics on the intestinal microbiota in broiler chickens. Probiotics administration (Lactobacillus paracasei J.R., Lactobacillus rhamnosus 15b, Lactobacillus lactis y and Lactobacillus lactis FO was made in different combination and at different age of broilers, respectively hatching until 42 days and only in the last week growth. In addition to probiotics, two of the experimental groups used two synthetic aminoacids, namely L threonine and DL methionine, used in excess of the broiler chicken requirements. At the end of the experiment (42 days), caecal content samples were taken. After isolating the caecum, the caecal content was sampled in sterile cryotubes and frozen to -80°C pending DNA extraction. The resulting DNA was subsequently used to detect the differences between the groups with and without probiotics by examining the microbiota composition. At the beginning, the phylogenetic differences were analyzed to establish dominant genders. The investigations performed showed that the use of probiotic microorganisms in various combinations entails changes in the intestinal microbiota. The pyrosequencing method was used to quantify the abundance of microorganisms with probiotic potential in the microbiota composition. Also, the number of microorganisms with probiotic potential changes after the use of probiotic microorganisms.