Bacterial community structure andinfection in cultured Koi(Anabas testudineus)fish species

Abstract

The study examined the presence of pathogenic and non-pathogenic bacteria species in cultured koi (Anabas testudineus). A total of twelve (12) samples were collected for the examination of bacteria. Pelleted feed with 2 g/kg Oxytetracycline (OTC) was applied in the pond. Tissues from the gill, intestine and skin were excised under aseptic conditions before and after (OTC) treatment for quantitative analysis. Bacterial population was decreased significantly after OTC treatment but it was significantly increased in control system in skin, gills and intestine of koi. Respective samples were inoculated in Brain Heart Infusion broth (BHI) and incubated then subsequently streaked on MacConkey Agar and Blood Agar for qualitative analysis. Bacteria colony was taken through a series of test for identification. Bacterial species belonging to the genus Staphylococcus, Pseudomonas, Flavobacterium, Escherichia, Salmonella and Vibrio were isolated. Bacterial infection in fish farm is crucial to the fish and consumer. The presence of these types of pathogens means the outbreak of serious fish disease in Bangladesh.