Fractal analysis of frequency-taxonomic profile of broiler's gut microbiota for studying the influence of probiotics on bird development

The article provides theoretical and empirical data about the probiotic effect on the microbiota bioconsolidation in the broiler intestines of the Smena cross. The results of such studies can be used to improve the quality and volume of meat products in large-scale production. The probiotics have been used to improve feed digestibility and accelerate bird development. To stimulate the transformation of plant substrates in the bird intestines, probiotics were used instead of antibiotics. The probiotics contained the bacteria Lactobacillus plantarum and Lactobacillus fermentum . The study goal is to develop a methodology for fractal analysis of the frequency-taxonomic profiles of operational taxonomic units (OTUs) of the microbiota into the bird intestines. Using the fractal methodology, the index of microbiom bioconsolidation of the bird intestines was calculated, which characterizes the biosystem self-organization of microflora and the efficiency of biochemical transformations of plant substrates in the bird intestines. In the experiment, the microflora was studied in one control and two experimental groups of birds. The OTUs profiles were obtained by the molecular genetic NGS method (Next Generation Sequencing). The key concept of fractal analysis of OTUs profiles was the concept of the elementary OTU fractal. The elementary OTU fractal is three OTUs, the frequencies of which form a geometric numerical sequence (for example, {0.5; 0.25; 0.125}). The OTU profiles may contain several elementary OTU fractals combined into one larger OTU megafractal. We assume that if the number of OTUs combined into the OTU megafractal increases, then biochemical transformations of plant substrate are carried out more efficiently and on a large scale, and the bird macroorganism receives more nutrients. Therefore, we define the bioconsolidation index of the broiler microbiome as the ratio of the number of OTUs in the OTU megafractal to the total number of OTUs in the OTU profiles. The fractal portraits of OTU profiles were used to identify elementary OTU fractals. The elementary OTU fractals were identified by the linear arrangement of three OTU images on fractal portrait. The fractal analysis confirmed that the bacterial probiotics increase the microbiom bioconsolidation in the bird intestines. The microbiome bioconsolidation index in the experimental groups of birds (0.82...0.86) was higher than this index in the control group of birds (0.55). According to the results of fractal analysis, probiotic No. 1 (with Lactobacillus plantarum ) is not recommended for use, and probiotic No. 2 (with Lactobacillus fermentum ) is recommended for use.