There has been a growing interest in feeding beneficial microorganisms to animals, such as Lactic Acid Bacteria (LABs), as an alternative to antibiotics. These microorganisms have been found to be preferred when isolated from their native environment of intended use. The purpose of this study was to determine the probiotic potential, temperature tolerance, acid tolerance and antibacterial capabilities of Lactic Acid bacteria isolated from pig colons in Masindi, Uganda. Five of the best performing Lactic acid bacteria were chosen for further analysis, with average inhibition diameters of 18.2mm (s.d 1.42) and 10.4mm (s.d 2.92) against E.coli and S.aureus, respectively. These Lactic acid bacteria were identified as Lactococcus garvieae, Lactobacilli fermentum, Lactobacilli pentosus, Lactococcus lactis, and Lactobacilli plantarum using the vitekII ID system. Their acid tolerance was studied at pH 2, 3, 5, 6.5 and 8, as well as their temperature tolerance at 40C, 250C, 370C and 420C. To assess tolerance, viable cell counts were taken at 0, ½, 1 and 2 hours intervals. The agar well diffusion assay was used to investigate the probiotic potential of Lactic Acid bacteria against Escherichia coli and Staphylococcus aureus as test organisms. Lactic acid bacteria were more active against E.coli than S.aureus, at p<0.05 level. Inhibition diameters for E.coli, ranged from 9mm (s.d 3.6) to 20mm (s.d 2.65), while inhibition diameters for S.aureus ranged from 9mm (s.d 4.58) to 14mm (s.d 1.73). All assay temperatures were tolerated for 2 hours, with 370C and 250C yielding the optimal growth. At 40C and 420C, strain mLb59 (Lactobacilli plantarum) increased slightly. With the exception of strain L59, the chosen LABS were tolerant to both alkaline and acidic pH for 2 hours of incubation, with no cell counts after 1 hour at pH2 and optimal growth at pH 6.5. According to the findings of this study, the LABS isolated from pigs in this study are of genera Lactococcus and Lactobacilli and show probiotic activity against E.coli and S.aureus. These LABS can withstand a wide pH and temperature range and can be recommended for further in-vitro testing as potential probiotic therapy.

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