ISOLATION AND CHARACTERIZATION OF LACTOBACILLUS SPECIES FROM FISH INTESTINE FOR PROBIOTIC PROPERTIES

Abstract

The aim of this research was to investigate the presence of species in freshwater fish and screen for probiotic properties. For this purpose, intestinal contents (n=12) were collected from 5 different freshwater fish such as Rohu ( spp.), Mangur ( spp.), Tengar (sp.), Baikari ( sp.) and Pungas ( spp.). Among the 120 isolates only 22  isolates were selected for further study. Based on morphological, biochemical characteristics, the isolates were identified as  (19 isolates), the predominant species isolated from 4 variety of fish (sp.,  sp.,  sp., sp.) and  (3 isolates) found only in sp. Identified species of  were assessed for  probiotic properties such as tolerance to bile, resistance to low pH values, antagonistic activities and antibiotic susceptibility pattern.  results showed that only 2 strains (1 of  and 1 of ) were able to meet the requirements. In the presence of relatively low pH (2) and high oxgall concentration (1%),  showed higher resistance (pH 2: 7CFU/ml; 120min.) and tolerance at (1%: 31CFU/ml; 120min) than . Using agar well diffusion method, both the species elicited antagonism against gram6negative fish pathogens, . and .  experiment reveals stronger antimicrobial actions of  against  (23.5 ± 0.5 mm at 0.2% glucose conc.) and  (22 ± 2 mm at 2% glucose conc.) than of . All the isolates of  when tested to 10 different types of antibiotics appeared more susceptible to most of the antibiotics and observed low resistance. However, the results obtained in this   experiment can only give an indication of   success, future research should include lactobacilli6based probiotic candidate from fish derived for large6scale   experiments.