ISOLATION AND CHARACTERIZATION OF POTENTIAL PROBIOTIC LACTIC ACID BACTERIA FROM THE GASTROINTESTINAL TRACT (GIT) OF POULTRY

Abstract

Lactic acid bacteria are one of the most important groups of microorganisms useful in animal and human health as probiotics. Probiotics are the health promoting living microorganisms and produces antimicrobial compounds such as organic acids, H2O2 and bacteriocins. Now a day, the use of antibiotics as growth promoters is questionable. In this case, probiotics have a potential to solve this problem as one of the alternatives to antibiotic growth promoters. The aim of this study was to isolate LAB from GIT of poultry and examine their potential uses as probiotic strains in vitro. For this purpose, 20 samples were collected from 4 parts of GIT obtained from 5 poultry (hens). In the present study physiological, biochemical, probiotic property and their safety status were done. Isolates were identified using molecular and Biolog methods at genus and species level respectively. In the present result, a total of 104 LAB isolates were isolated and screened for their antimicrobial activity against Escherichia coli ATCC25922, Salmonella typhimurium ATCC13311 and Staphylococcus aureus ATCC25923. Out of the 104, ten isolates of LAB were selected according to their levels of antimicrobial activities for further analysis of physiological, biochemical, probiotic and molecular characteristics. The results indicates that selected LAB isolates were exhibited excellent potential probiotic characteristics including homofermentative metabolic activity, ability to ferment different sugars, tolerance to different temperatures and salt concentrations. In addition, the hydrophobicity test indicated that some of the isolates exhibited higher percent (51-100%) of hydrophobicity towards chloroform. Furthermore, identification at molecular level was shown that the isolates belonged to the group of LAB with genera specific primers that produced a PCR product of about 350 bp. Finally, LAB isolates were identified at species level using Biolog method. In general, these selected LAB isolates have beneficial probiotic properties that make them safe to use in different applications. This study provides baseline information for further investigations of LAB isolates in vivo.