Comparative Study on Biological Characteristics and Functions of Three Porcine-Derived Lactic Acid Bacteria

To screen high-quality porcine-derived lactic acid bacteria for swine production, this study compared growth performance, acid production, acid and bile salt tolerance, and genome characteristics of Lactiplantibacillus plantarum (MRS002), Lactobacillus amylovorus (MRS003), and Ligilactobacillus salivarius (MRS004). All three strains showed typical anaerobic growth. L. amylovorus had a longer growth cycle and higher biomass, while L. plantarum and L. salivarius grew faster and produced more acid, with pH values reaching 4.2 and 4.3 at 24 h. L. plantarum and L. salivarius also exhibited higher survival rates under 0.3% bile salt and pH 2.0 stress. Genome annotation revealed that more than 50% of genes were related to metabolism in all strains. L. plantarum possessed the most comprehensive metabolic and stress-resistance gene networks; L. amylovorus was enriched in starch-degradation pathways; and L. salivarius showed unique advantages in aromatic amino acid metabolism. In summary, L. salivarius MRS004 displays superior probiotic traits, L. plantarum MRS002 has broad adaptability, and L. amylovorus MRS003 is suitable for high-starch feed fermentation. This study provides theoretical support and strain resources for probiotic development and antibiotic-free breeding.