Abstract:
The studies for selection of lactic acid bacteria (LAB) that has potential for probiotics in animals were carried base on the method described in ISO-15214. The 30, 25, 15, 9 and 1 indigenous samples were taken from chickens, farm animals feces, fresh water fishes, fermented foods and a commercial probiotic product, respectively. The results yielded 216 isolates, with different morphology; rods (121/216), cocci in chain (63/216) and tetrads (32/216). The isolates from a commercial probiotic yield, 2 rods and 1 coccus in chain. Fifty-three isolates, including 3 isolates from the commercial probiotics were randomly selected and subjected for further studies. Antimicrobial susceptibilities, acid tolerance, bile tolerance and antimicrobial activities were examined. The results revealed 6 isolates, C43-1, C72-1, F23-1, C70-2, C76-1 and C80-2 of potential probiotics bacteria and 3 commercial probiotic isolates, Fr-A, Fr-B and Fr-C. All of the potential had a wide and broad resistance to the tested antimicrobial and chemotherapeutic agents (aztreonam, streptomycin, colistin, tetracycline, nalidixic acid and vancomycin). All of the tested isolates could tolerate to acidity at pH 2.5 and 4 % bile salt solution. All of the tested isolates could inhibit E. coli ATCC 25922, Listeria innocua DMST 9011, Listeria monocytogenes DMST 17303, Salmonella Typhimurium ATCC 13311, Salmonella Cholerasuis ATCC 10708, Bacillus cereus ATCC 11778 and Pseudomonas aeruginosa ATCC 27853 but did not produce bacteriocin. When comparing the phenotypic differences and 16S rDNA sequence, the rod-shaped isolates C43-1, C72-1, F23-1, Fr-A and Fr-B were similar to Lactobacillus salivarius, L. plantarum, L. plantarum, L. casei and L. plantarum, respectively. The cocci chain isolates C70-2, C76-1 and Fr-C were similar to Enterococcus faecium, E. hirae and E. faecium, respectively. The tetrad (C80-2) was similar to Pediococcus pentosaceus. This study described method which for the selection of potential probiotics and successfully identified 4 isolates which are L. plantarum C72-1, L. Plantarum F23-1, E. faecium C70-2 and P. pentosaceus C80-2 respectively, which had comparable in vitro probiotic activities commercial import products.