Abstract:
Hilsha (Tenualosa ilisha) is a popular, tasty fish found in the rivers of Bangladesh round the year.It is now generally recognized that the digestive tract of fish particularly the intestine contains a large number of bacteria. Sample were collected from Meghna river in Chandpur for gut microbial analysis. During the study sample were collected in two different sesson viz. summer and winter. Four types of bacteriological culture media viz. EMB agar medium for coliform, XLD agar for SalmonellaShigella, PYG media for heterotrophic bacteriaand TCBS for Vibrio were used to assess the quantitative and qualitative study of bacteria associated with the fresh hilsa fish collected from Meghna river in Chandpur. The bacterial load of fresh fish samples was found to be ranged between 11.6 x〖 10〗^8to 1.3 x〖10〗^4cfu/g, 3.56 x〖10〗^6 to 4 x〖 10〗^3cfu/g, 5 x〖 10〗^8to 2.7 x〖10〗^4cfu/g and 9.5x〖10〗^5 to 5.4x〖10〗^3in PYG agar, EMB agar, and TCBS agar, XLD agar respectively. Highest bacterial count 11.6 x〖 10〗^8, 3.56 x〖10〗^6, 5 x〖 10〗^8, 9.5x〖10〗^5 in PYG agar, EMB agar, and TCBS agar, XLD agar medium. All of the highest bacterial count found in summer. During this study 123 bacterial colonies were isolated. Among them 27 bacterial isolates were selected for further study. Out of 27 bacterial isolates 22 were Gram positive and 5 were Gram negative. The provisionally identified Gram positive bacteria were Bacillus cereus (2), Bacillus subtilis (4), Bacillus coagulans (3), Renibacterium salmoniarum (2), Bacillus licheniformes (1), Bacillus pumilus (3), Erysipelothrix rhusiopathiae (1), Bacillus alvei (3), Bacillus polymyxa (1), Renibacterium salmoniarum (2) and Gram negative bacteria were Legionella micdadei (2), Vibrio nereis (1), Legionella pneumophila (1), Pasteurella multocida (1). The outcome of the study indicates that gut microflora of Hilsa may not only be pathogenic to fish but also for human health which can cause foodborne disease.
