Recent years have witnessed a tremendous interest in the use of essential oils in biomedical applications due to their intrinsic antimicrobial, antioxidant, and anticancer properties. However, their low aqueous solubility and high volatility compromise their maximum potential, thus requiring the development of efficient supports for their delivery. Hence, this manuscript focuses on developing nanostructured systems based on Fe₃O₄@SiO₂ core–shell nanoparticles and three different types of essential oils, i.e., thyme, rosemary, and basil, to overcome these limitations. Specifically, this work represents a comparative study between co-precipitation and microwave-assisted hydrothermal methods for the synthesis of Fe₃O₄@SiO₂ core–shell nanoparticles. All magnetic samples were characterized by X-ray diffraction (XRD), gas chromatography-mass spectrometry (GC-MS), Fourier-transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), zeta potential, scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetry and differential scanning calorimetry (TG-DSC), and vibrating sample magnetometry (VSM) to study the impact of the synthesis method on the nanoparticle formation and properties, in terms of crystallinity, purity, size, morphology, stability, and magnetization. Moreover, the antimicrobial properties of the synthesized nanocomposites were assessed through in vitro tests on Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, and Candida albicans. In this manner, this study demonstrated the efficiency of the core–shell nanostructured systems as potential applications in antimicrobial therapies.

Background: Food and feed supplements containing microorganisms with probiotic potential are of increasing interest due to their healthy promoting effect on human and animals. Their mechanism of action is still unknown. Using a microarray approach, the aim of this study was to investigate the differences in genome-wide gene expression induced by a mixture of three Lactobacillus strains (L. rhamnosus, L. plantarum, and L. paracasei) in intestinal porcine epithelial cells (IPEC-1) and to identify the genes and pathways involved in intestinal barrier functions. Methods: Undifferentiated IPEC-1 cells seeded at a density of 2.0 × 10⁵/mL in 24-wells culture plates were cultivated at 37 °C and 5% CO₂ until they reached confluence (2–3 days). Confluent cells monolayer were then cultivated with 1 mL of fresh lactobacilli (LB) mixture suspension prepared for a concentration of approximately 3.3 × 10⁷ CFU/mL for each strain (1 × 10⁸ CFU/mL in total) for 3 h and analyzed by microarray using Gene Spring GX v.11.5. Results: The functional analysis showed that 1811 of the genes modulated by LB treatment are involved in signaling (95% up-regulation, 121 genes with a fold change higher than 10). The most enhanced expression was registered for AXIN2 (axis inhibition protein 2-AXIN2) gene (13.93 Fc, p = 0.043), a negative regulator of β-catenin with a key role in human cancer. LB affected the cellular proliferation by increasing 10 times (Fc) the NF1 gene encoding for the neurofibromin protein, a tumor suppressor that prevent cells from uncontrolled proliferation. The induction of genes like serpin peptidase inhibitor, clade A member 3 (SERPINA 3), interleukin-20 (IL-20), oncostatin M (OSM), granulocyte-macrophage colony-stimulating factor (GM-CSF), and the suppression of chemokine (C-X-C motif) ligand 2/macrophage inflammatory protein 2-alpha (CXCL-2/MIP-2), regulator of G-protein signaling 2 (RGS2), and of pro-inflammatory interleukin-18 (IL-18) genes highlights the protective role of lactobacilli in epithelial barrier function against inflammation and in the activation of immune response. Conclusion: Gene overexpression was the predominant effect produced by lactobacilli treatment in IPEC-1 cells, genes related to signaling pathways being the most affected. The protective role of lactobacilli in epithelial barrier function against inflammation and in the activation of immune response was also noticed.

A total of 15 strains of lactic acid bacteria (LAB) were isolated from the broiler chicken’s gastrointestinal tract. All isolates were phenotypical and genetically identified. Among these isolates, only six were biochemical (API 50 CHL and ABIS soft) and genetically (16S rRNA sequencing) confirmed as Lactobacillus acidophilus, Limosilactobacillus fermentum, Levilactobacillus brevis, and Ligilactobacillus salivarius. Probiotic properties, including tolerance to pH (pH 2.0 and 3.0), bile salts (0.3% oxgall), hemolysis activity, and antibiotic susceptibility, were evaluated. Three isolates of the latter isolates showed high resistance at low pH values (73.74% to 98.20%) and bile salt concentrations (77.89% to 99.49%). The antibiotic test presented 100% resistance of LAB to gentamicin, lincomycin, enrofloxacin, and streptomycin lower than the 0.5 mm inhibition zone diameter. Selected strains (L. acidophilus IBNA 64, L. salivarius IBNA 33, and L. salivarius IBNA 41) were exposed to the spray-drying process based on observable probiotic potential. A maltodextrin-glucose solution was used as a thermoprotectant. After spray drying, a reduction in strain viability was noted (10⁸ to 10⁴ CFU/g). In conclusion, only L. salivarius (IBNA 33 and IBNA 41) could be used as a possible probiotic, and further studies are needed to ensure their safe application in the animal nutrition field with beneficial effects for improving performance and pathogen microorganism control from intestines equilibrating the microbiota composition.

The objective of this study was to isolate, identify, preserve and determine the quantitative level of the Lactobacillus strains from the gut content of 45-day-old chickens broilers; to test the viability of these strains preserved at 4 ºC and room temperature (20 ± 2 ºC). Lactobacillus strains were isolated, phenotypically identified and preserved from the gut content of 17 chickens broilers. Identification was performed by morphological, cultural and biochemical characters examination, using apiwebTM and ABIS online software. The quantitative level of Lactobacillus strains in intestinal content (105 - 109 CFU/g) and the viability of strains preserved at 4 ºC and at room temperature (from 8 days to 9 months) was also determined. Twenty-three strains of L. acidophilus, L. brevis, L. plantarum, L. fermentum and L. salivarius from the gut content of chickens broilers were isolated, phenotypically identified, and preserved. Of these, L. plantarum, L. fermentum and L. acidophilus biotype 1 strains were technologically and ecologically suitable to continue the testing of probiotic traits.

Fourteen lactic acid bacteria (LAB) strains were isolated from the intestinal tract and feces of piglets. Among these isolates, only twelve were biochemically (API 50 CHL and ABIS online for bacterial identification) and genetically (16S rRNA sequencing) confirmed as Limosilactobacillus fermentum, Lactobacillus acidophilus, and Lactiplantibacillus plantarum. Experiments to evaluate the probiotic potential of the isolates including pH tolerance (pH 2.0 and 3.0), bile salts (0.3% ox gall) resistance, hemolysis activity, antibiotic susceptibility, and high-temperature resistance were tested. Only two isolates from identified strains exhibited high survival rates when exposed to low pH and bile salts, these were L. acidophilus IBNA 76 and L. plantarum IBNA 84. The antibiotic test presented 100% resistance of both strains to gentamicin, kanamycin, lincomycin, colistin sulfate, erythromycin, amikacin, oxytetracycline, enrofloxacin, streptomycin, and tilmicosin, lower than the 0.6 mm inhibition zone diameter. Promising isolates (L. acidophilus IBNA 76 and L. plantarum IBNA 84) were exposed to the spray-drying technique based on visible probiotic potential and survival rates. Carrier matrix material was used as a maltodextrin-glucose solution. The encapsulation probiotic isolated survived both over 67% and 77%, corresponding to a decrease in strain viability from 10⁹ to 10⁷ CFU/g. After further in vitro evaluations, the findings of this study showed that, from all LAB strains, L. acidophilus IBNA 76 and L. plantarum IBNA 84 may be considered probiotic candidates for animal nutrition and may have promising performance in piglet feed due to their origin of isolation.