Gamma-Aminobutyric Acid (GABA) Producing Lactobacillus plantarum TSUB-17 and Probiotic Properties for Using as Probiotics Additive in Swine Feed

Due to the use of probiotics in animal husbandry has recently increased, the selection of high-quality probiotic strains is crucial. Since the uses of probiotics for animal feed supplements have to be applied at high doses of bacteria to be effective, the cultures’ safety is essential. This study successfully isolated the novel Lactobacillus sp. from swine fecal samples and identified it as L. plantarum TSUB-17. The L. plantarum TSUB-17 exhibited excellent probiotic properties, including 100 % resistance to 3 % acids and 1 % bile salts, and effectively inhibits pathogenic bacteria such as Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae and Salmonella Typhimurium (isolated ESBL strain). L. plantarum TSUB-17 was also found to adhere to the intestinal wall and form a biofilm. Furthermore, the bacteria have revealed some unique properties of GABA production and detected the glutamate decarboxylase B (gadB) gene similar to L. brevis both in nucleotide sequence and secondary structure of the glutamate decarboxylase enzyme that was deduced from the nucleotide. The isolated bacteria also have antioxidant activity, and most importantly, the isolated strain was safe; it is non-hemolysis and susceptible to the tested antimicrobials. Therefore, L. plantarum TSUB-17 is suitable for further development as a probiotic additive in animal feed. HIGHLIGHTS This study successfully isolated Lactobacillus plantarum TSUB-17 with a high potential to develop as a probiotic for animals. The isolated bacterium has excellent properties: It tolerates high levels of acids and bile salts. It is effective against many pathogenic bacteria, produces gamma-aminobutyric acid (GABA) and shows high levels of antioxidant activity. Moreover, L. plantarum TSUB-17 is very safe due to its non-hemolytic strain and susceptibility to numerous antimicrobial drugs. GRAPHICAL ABSTRACT