IN VITRO PROBIOTIC PROPERTIES OF A LACTIC ACID BACTERIA ISOLATED FROM A BROILER CHICKEN

Mihaela Dumitru, I. Sorescu, Georgeta Ciurescu, Cristina Tabuc, Mihaela Hăbeanu, Nicoleta-Raluca Chelaru

Abstract
    This study was conducted in order to evaluate in vitro the probiotic properties of lactic acid bacteria (LAB) isolated from ileum intestinal content tract of a healthy broiler (45-d-old Cobb 500). The isolate was assayed morphologically, culturally, biochemically. The tolerance to low pH and bile salt were tested as well. Phenotypically, the isolate strain was identified to be Lactobacillus acidophilus. The new strain was conserved as Lactobacillus acidophilus IBNA 64 in the Collection of INCDBNA. It is Gram-positive Bacillus, thin, non-spore forming, appears isolated, rarely in the diploid form, in short chains or in small irregular piles in culture of 24h in Oxoid MRS broth and MRS agar medium. The strain is an aerotolerant bacteria. The identification and analysis of the biochemical characteristics was performed by catalase assay, API 50 CHL Biomerieux strips, apiweb API 50 CHL V 5.1 soft (Lactobacillus acidophilus 1, 74.4% ID and L. crispatus 19.0% ID) and ABIS online (Lactobacillus acidophilus ~ 88.3%). The strain showed good viability at pH 7±2 (8.32±0.330 log CFU/mL), respectively was able to resist at pH 3 (7.14±0.133 log CFU/mL) and 0.3% bile salts (7.56±0.19 log CFU/mL) during 3 h exposure. Results obtained provide some probiotic properties for L. acidophilus, but further studied will be done until to use for in vivo test in poultry feed.