PROBIOTIC CHARACTERIZATION OF THE LACTOBACILLUS ISOLATES FROM THE GASTROINTESTINAL TRACT OF POULTRY IN PAKISTAN

This study was conducted to screen and select the potential probiotic bacteria from the gastrointestinal tract of poultry birds. Twenty four isolates of Lactobacilli were selected after the optimization studies on 84 isolates. These isolates were evaluated for their probiotic ability using standard criteria i.e. tolerance to acidic conditions, bile concentration, and osmotolerance. Further, in vitro tests were conducted for determining antibacterial activity of the isolates against Salmonella and E. coli. Out of the 24 isolates, 16 isolates were able to grow at a pH of 2 and tolerate bile concentration of 0.3%. The DNA of these 16 isolates was amplified using Lactobacillus-specific primer followed by sequencing of the amplified region. The results indicated that the isolates shared from 55 to 99% homology with the sequences of different Lactobacillus species in the NCBI database. The various isolates identified through specific gene sequence analysis included L. gasseri (61%), L. johnsonii (19%), L. rodentium (10%), L. kullabergensis (5%), and L. bombicola (5%). It was concluded that 16 isolates fulfill the criteria of probiotic ability but one group of isolates from chicken intestine showed most efficient potential of surviving critical conditions along with inhibition of selected enteric pathogens.