To study the effect of probiotic strains of the genus Bacillus on the state of internal organs and humoral immunity of Coturnix coturnix and Mus musculus

Studies of Bacillus microorganisms open up broad opportunities for the use of probiotic strains in various fields of biotechnology. Bacillus microorganisms exhibit antiallergic and antioxidant effects, and produce antibacterial substances, bacteriocins and enzymes, which makes them promising for use as dietary supplements in agriculture and the food industry. Bacillus-based probiotics, especially in spore form, are resistant to aggressive conditions and are able to activate a nonspecific cellular immune response. In our study, we evaluated 5 cultures of Bacillus microorganisms for the development of probiotic drugs, with a focus on stimulating the humoral antigen response. The studies were conducted on Coturnix coturnix quails of the Texas breed (aged 14 days), the birds were divided into 5 experimental groups and 1 control (n = 7), as well as on ICR mice (CD1), which were divided into one experimental group and one control (n = 8). Antagonistic, hemolytic, galactosidase and DNase activities, as well as sensitivity to kanamycin, were studied. Immunogenicity and invasiveness of cultures were screened by evaluating sera in the immunofluorescence agglutination reaction. The length of intestinal villi in experimental animals was determined, and organs were weighed to determine mass coefficients. It was found that B. halotolerans strain No. 5.6 effectively lengthens intestinal villi in quails, but does not affect the mucous membrane in mice. Our studies confirmed that many B. subtilis strains are invasive, which is considered to be the main factor determining their immunostimulatory effects. This property is also useful for delivering vaccine antigens through mucous membranes, but the results showed that immunogenicity and the ability to overcome food tolerance in B. subtilis do not depend solely on invasiveness. Other Bacillus species, such as B. halotolerans, may hold promise for probiotic development.

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