Microbial Profiling of Dropsy Diseased Empurau (Tor tambroides)

The highly profitable riverine fish with excellent taste, Tor tambrodies (commonly known as Empurau) is an important fish species in aquaculture business. The study was performed to identify bacterial pathogens from dropsy diseased T. tambroides, compare the isolated bacteria from dropsy and healthy Empurau as well as to assess their sensitivity to antibiotics. Pure culture of bacteria using spread plate techniques, Gram’s Staining, KOH string test, and 16s rRNA sequencing were performed to identify the causative agents of the diseased fish. Five types of antibiotics discs namely, Ampicilin (10μg), Tetracycline (30μg), Chloramphenicol (30μg), Clindamycin (2μg) and Morepenem (10μg) were used to test the sensitivity of the isolated bacteria. Three pathogenic bacteria such as Pseudomonas fluorescens, Citrobacter freundii and Aeromonas veronii were identified in the studied diseased Empurau (T. tambroides). Among them, Aeromonas veronii were only identified in the guts of healthy fish but are not identified in dropsy fish guts. P. fluorescens, P. congelans and Citrobacter freundii was found only in diseased Empurau which may perhaps responsible for the Dropsy. The results of the antibiotic sensitivity test showed multi-resistances of the identified bacteria to the tested antibiotics. Tetracycline (30μg) and Morepenem (10 μg) was found sensitive to the identified bacteria. Multiple reaction was reported on the use of Ampicilin (10μg) and Chloramphenicol (30μg), but the studied bacteria were resistant to Clindamycin (2μg). The results of this study will be helpful to the fish farmers for the management of bacterial diseases in fish. Further research on the biochemical characterization and proper analysis on disease management of capture bred Empurau fish could be done to improve the aquaculture sectors