The oil cakes of essential oil plants were screened for prebiotic properties for further development of prebiotic feeds for livestock animals based on these essential oil plants’ extracts. For screening, a microbiota model of the chicken cecum, which was created on the basis of an artificial intestinal medium, was used. This model renders it possible to simulate conditions close to intestinal ones. Oligofructose, inulin, β-glucan, psyllium seeds, and apple fiber at a concentration of 0.5% were used as substances with known prebiotic properties. The oil cake concentration was 0.5%, 1%, 2%, and 4%. The direct antimicrobial effect of the cakes on intestinal bacteria was also investigated. The ability of the cakes to stimulate a decrease in the pH level by Lactobacillus was studied under conditions close to intestinal ones. It was shown that the cakes of big seed false flax (Camelina sativa), brown mustard (Brassica juncea), and spicate lavender (Lavandula angustifolia) exhibit prebiotic properties in relation to the microbiome of chickens in model experiments. They enhance the acid-forming properties of lactic acid bacteria, thereby lowering the pH of the medium. This leads to a decrease in the number of Enterococcus, Escherichia coli, and lactose-positive bacteria, as well as a complete suppression of Proteus. The optimal oil cake concentrations are 1% and 2%. These oil cakes are promising sources of prebiotics for the development of prebiotic feed for agriculture.

Cerium oxide nanoparticles (CeO₂NPs) possess unique physicochemical properties that make them promising compounds for medical and industrial applications. However, variations in synthesis methods, particle size, and surface characteristics may influence their potential toxicity. This study provides a comparative analysis of CeO₂NPs synthesized via three methods (citric, dextran, and uncoated modifications) to evaluate their toxicity, antioxidant mechanisms, and genoprotective potential using a panel of Escherichia coli-based lux-biosensors. Our data indicate that all of the tested CeO₂NPs exhibit high biocompatibility with no significant toxicity or genotoxicity at physiological concentrations (10⁻⁴–10⁻² M). The citrate-modified nanoparticles demonstrated pronounced catalase-mimetic activity, acting as the most effective scavengers against hydrogen peroxide. Conversely, the dextran-modified nanoparticles exhibited the highest antimutagenic potential, reducing dioxidine-induced DNA damage by over 56%. Thus, beyond establishing biocompatibility, this study highlights the potential of using specific CeO₂NP modifications for targeted therapy depending on the oxidative pathway involved. This suggests their potential for application as antioxidant and antimutagenic agents in both human and veterinary medicine.

This work investigates the impact of rifampicin-resistance mutations on the synthesis of secondary metabolites with antioxidant, DNA-protective, and SOS-inhibitory properties in two probiotic strains Bacillus amyloliquefaciens B-1895 and B. subtilis KATMIRA1933. Rifampicin-resistant (RifR) mutants of these strains demonstrated significantly enhanced biological activities compared to their wild-type counterparts. Antioxidant activity increased by 30.39% in B. subtilis KATMIRA1933 and 24.55% in B. amyloliquefaciens B-1895 mutants, while DNA-protective activity rose by 6.67 and 6.27%, respectively. SOS-inhibitory activity also improved, notably by 17.27% in B. subtilis mutants and 3.12% in B. amyloliquefaciens. Genomic analysis revealed the presence of genes responsible for the synthesis of non-ribosomal peptides and polyketides, which are likely contributors to these enhanced activities. These findings suggest that RifR mutants can serve as effective producers of metabolites with antioxidant, DNA-protective, and SOS-inhibitory properties, offering potential applications in agriculture and pharmacology.

This work is aimed at studying the effects of rifampicin resistance mutations on the synthesis of secondary metabolites with antioxidant and DNA-protective properties. We used probiotic strains of the genus Bacillus : B. amyloliquefaciens B-1895 and B. subtilis KATMIRA1933. The antioxidant, DNA-protective activity, and the ability to suppress the SOS-response in B. amyloliquefaciens B-1895 and B. subtilis KATMIRA1933 rifampicin-resistant mutants have been studied for the first time. It has been found that antioxidant, DNA protective, and SOS-inhibiting activity is higher in rifampicin-resistant mutants than that of original strains. According to the study results, it has been discovered that the antioxidant, DNA-protective and SOS-inhibitory activity in mutants B. amyloliquefaciens B-1895 and B. subtilis KATMIRA1933 resistant to rifampicin is higher than in control strains, which indirectly proves the pleiotropic effect of the rpoB gene on these activities.

Three probiotic strains were selected for their potential ability to break down the lactone ring in some mycotoxin molecules. Two of them have previously demonstrated their effectiveness in reducing the toxicity of mycotoxin-contaminated cattle feed. The reduced weight gain observed in groups of young heifers whose feed was contaminated with mycotoxins was completely eliminated by a synbiotic preparation containing these strains, and the indicators returned to control values. In this study, we present the results of whole-genome sequencing and a functional analysis of these strains’ genomes. Although preliminary screening was concentrated on cellulolytic and lactonase activity, while the latter allows bacteria to destroy mycotoxins that possess lactone rings in their structure, this genome analysis revealed gene clusters for synthesizing bioactive secondary metabolites, that are capable of mediating other types of probiotic activity (e.g. non-ribosomally synthesized lipopeptides). The biosafety of these strains was also evaluated via antibiotic resistance genes analysis. The characteristics described above make these strains promising candidates as effective probiotics for livestock.