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[6-1130-P-05] Probiotic characterization of thermotolerant Lactobacillus johnsonii isolated from broiler intestine
Keywords:Lactobacillus johnsonii, probiotic, broiler gastrointestinal tract, feed supplement
Bacterial community in human and animal gastrointestinal tract (GI) are diverse. In GI tract of healthy hosts, lactic acid bacteria (LAB) can be found as dominant flora. Some strains of LAB have been accepted as probiotic due to the fact that they contribute many health benefits to host. Several probiotics are isolated and applied in functional food and feed products for the specific consumers, including human and animal. Nowadays, thermotolerant probiotics are of interest to industrial application, because of their high heat-resistant ability in food and feed manufacturing. The aims of this study were to isolate thermotolerant LAB from broiler intestine and evaluate their probiotic characteristics for monogastric feed application. Two promising isolates, CK3 and VCF29 were selected and identified by 16S rRNA gene sequencing. Both of them were identified to Lactobacillus johnsonii with 100% similarity. L. johnsonii CK3 and L. johnsonii VCF29 were not haemolytic strains and their percentages of auto-aggregation value were 18.37±5.30 and 9.19±0.71, respectively. Resistibility to acidity at pH 2.5 and 0.3% bile acid of L. johnsonii VCF29 (94.68 and 94.73%) were greater than those of L. johnsonii CK3 (62.48 and 87.34%). Both strains were susceptible to cefoxitin, chloramphenicol, vancomycin, ampicillin and ceftriaxone. In addition, they exhibited antibacterial activity against pathogenic Staphylococcus aureus, Proteus vulgaris, Salmonella Typhimurium and Escherichia coli. It might be indicated that L. johnsonii CK3 and VCF29 could be good probiotic candidates applied as functional feed supplement for monogastric animal, especially broiler.