<p>An important link in solving the problem of healthy food is the intensification of the livestock, poultry and fish farming, which is possible only in the adoption and rigorous implementation of the concept of rational feeding of animals. In the implementation of this concept required is the application of probiotic preparations. Currently, there is an increased interest in spore probiotics. In many ways, this can be explained by the fact that they use no vegetative forms of the bacilli and their spores. This property provides spore probiotics a number of advantages: they are not whimsical, easily could be selected, cultivated, and dried. Moreover, they are resistant to various factors and could remain viable during a long period. One of the most famous spore microorganisms, which are widely used in agriculture, is <em>Bacillus subtilis</em>. Among the requirements imposed to probiotic microorganisms is mandatory – antagonistic activity to pathogenic and conditional-pathogenic microflora. The article presents the results of the analysis of antagonistic activity of collection strains of <em>B. subtilis</em>, and strains isolated from commercial preparations. We studied the antagonistic activity on agar and liquid nutrient medias to trigger different antagonism mechanisms of <em>B. subtilis</em>. On agar media, we applied three diffusion methods: perpendicular bands, agar blocks, agar wells. We also applied the method of co-incubating the test culture (<em>Escherichia coli</em>) and the antagonist (or its supernatant) in the nutrient broth. Our results demonstrated that all our explored strains of <em>B. subtilis</em> have antimicrobial activity against a wild strain of <em>E. coli</em>, but to varying degrees. We identified strains of <em>B. subtilis</em> with the highest antagonistic effect that can be recommended for inclusion in microbial preparations for agriculture.</p><p><em><br /></em><em></em></p>

<p><em>Bacillus subtilis</em> is the most studied bacterium from genus <em>Bacillus</em> and this microorganism is widespread in nature. <em>B. subtilis</em> is often found in fresh and seawater, in the rhizosphere, in the soil (especially contaminated with feces and manure). The large variety of strains are available in collections of microorganisms, but strains isolated from the rhizosphere of various plants are particularly interesting for science and practical use. At the same time, the morphological criterion (the form and other features of the colonies) is the main one in the identification of <em>B. subtilis</em> at the first stages of the study and allows to refuse of extraneous strains before use more expensive methods and materials. The article presents the description of the morphological diversity of <em>B. subtilis</em> strains that are used in agriculture. Typical R–colonies are characteristic of bacteria <em>B. subtilis</em>, and we established 2 morphologically diverse forms of these colonies in the studied strains.</p><p> </p>

The ability of bacteria to quickly acquire antibiotic resistance and transfer it among different groups are created a global problem, since antibiotics are used not only in medicine, but also in agriculture. That is why to study of the antibiotic sensitivity of not only pathogenic bacteria, but also of beneficial microbes like Bacillus spp. is extremely important. Our results demonstrated that all the studied strains of the B. subtilis group were highly sensitive to cephalexin and enrofloxacin, while resistant to oxacillin. The B. subtilis B-5449 strain was the least resistant to the studied antibiotics, and the B. subtilis B-2896 strain was the most resistant.

The influence of the experimental probiotic “Plantarum” on the productive and some exterior-constitutional features of dairy Saanen breed goats was studied. The preparation was developed in the microbiology laboratory of milk and dairy products of the department “Siberian Research Institute for Cheese Making” of the Federal State Budgetary Scientific Institution “Federal Altai Scientific Center of Agrobiotechnology” (FSBSI FASCA). The composition of the preparation includes pure cultures of probiotic strains of lactobacilli and propionic acid bacteria from the “Siberian collection of microorganisms”. The probiotic preparation in liquid form was introduced into concentrated feed (oats). The positive effect of the use of the probiotic “Plantarum” on the average daily milk yield of the experimental groups of fully developed (assessed by the exterior) pregnant female goats was established. A significant increase in milk yield was observed in the second and third groups by 1.66% (p < 0.05) and 3.27% (p < 0.05), respectively. With an increase in the average daily milk yield, the main physical and chemical parameters of milk (mass fraction of fat, mass fraction of protein) of the experimental groups did not decrease. There was a tendency to improve the safety of young animals in the second and third groups with an increase in the probiotic dose. At this stage of the work, the optimal dose with the maximum positive effect of introducing the probiotic preparation into the diet of experimental animals (0.8 ml/kg of body weight per day) was established. In this connection, it is necessary to conduct an additional experiment with an increase in the dose of probiotic administration when feeding it to experimental animals.

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