Identification, Growth Profile and Probiotic Properties of Autochthonous Intestinal Bacteria of Sagor catfish (Hexanematichthys sagor).

The prevalence of antibiotic resistant bacteria in aquaculture has reached alarming proportions and intensified the search for microbe derived antimicrobial compounds. This study isolated bacteria from the intestine of Sagor catfish (Hexanematichthys sagor) and screened it for antagonistic properties. Five out of 334 bacterial isolates inhibited growth of fish pathogens. The 5 bacterial strains included relatives of Shewanella haliotis, Myroides odoratimimus, Vibrio harveyi, Vibrio alginolyticus and Alcaligenes faecalis. The growth profiles and probiotic properties of these bacteria were examined. The results showed that the isolate 9 (3) 7.5.2.1, whose closest relative was S. haliotis exhibited growth and probiotic advantage compared to the other bacterial strains, such as highest doubling time and the ability to survive at all experimental temperatures (18 to 60 degrees C), and bile concentrations (0.01 to 1.00%) and pH (pH2 to 9). While the bacteria with probiotic properties were successfully isolated. Further study is necessary to examine the efficiency of the probiotic candidate bacteria in boosting fish immunity against pathogens.