Study of safety and probiotic properties of normal flora of the genus Lactobacillus

Relevance . Today, the search for safe, effective and promising strain cultures exhibiting high probiotic properties as the main components of pharmacological microbial agents is a relevant area. The article presents the results of the study of probiotic properties and safety indicators of the normal flora of the genus Lactobacillus . Materials and methods . The properties of Ligilactobacillus agilis , Lacticaseibacillus paracasei and Ligilactobacillus salivarius , which were isolated from the caecum of turkeys, were studied as probiotic strains. Of the probiotically significant properties of beneficial microflora, the antagonistic effect on pathogenic microorganisms, adhesive and anti-adhesive properties were analyzed in cellular models (ram blood erythrocytes and intestinal enterocytes of rat embryos). The safety of the probiotic strains was assessed by their ability to produce hemolysin by seeding them on a dense nutrient medium with defibrinated ram blood, as well as by intraperitoneal administration of a suspension of the test microorganism killed by heating in its maximum concentration. Results . A set of microbiological studies demonstrated that the studied beneficial strains exhibit probiotic properties to varying degrees. The results of studying the antagonistic properties showed that the growth inhibition zone of opportunistic microorganisms varied within 4–14 mm depending on the test culture. When analyzing adhesiveness and antiadhesion, the best results were demonstrated by the strains Ligilactobacillus agilis and Lacticaseibacillus paracasei . When assessing the safety, it was found that the studied representatives of lactic acid bacteria do not form a hemolysis zone on the nutrient medium, and when intraperitoneally administered to laboratory animals, they do not cause signs of impairment of their health or loss of body weight.