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 Lactobacillus plantarum (MRS002), Lactobacillus amylovorus (MRS003), and Lactobacillus salivarius (MRS004). All experiments were performed with three biological replicates, and data were analyzed using the GraphPad Prism software 8.4.3 by one-way analysis of variance (one-way ANOVA) followed by Tukey's multiple comparison test (significance level p < 0.05). All three strains showed typical anaerobic growth. L. amylovorus MRS003 had a longer growth cycle and higher biomass, while L. plantarum MRS002 and L. salivarius MRS004 grew faster and produced more acid, with pH values reaching 4.2 and 4.3 at 24 h, respectively. L. plantarum MRS002 and L. salivarius MRS004 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 MRS002 possessed the most comprehensive metabolic and stress-resistance gene networks; L. amylovorus MRS003 shows genomic enrichment in starch-degradation pathways and appears promising for high-starch feed fermentation; and L. salivarius MRS004 showed unique advantages in aromatic amino acid metabolism (e.g., phenylalanine, tyrosine, and tryptophan biosynthesis). In summary, based on the evaluated in vitro indicators, L. salivarius MRS004 has more favorable phenotypic characteristics, L. plantarum MRS002 has broad adaptability, and L. amylovorus MRS003 is suitable for high-starch feed fermentation. This study provides a theoretical basis for the research and development of probiotic products.