The present study was undertaken to reveal the microflora in the intestines of various marine fish.
For the enumeration and isolation of bacteria smear plate method was employed using “modified ZOBELL 2216 agar medium”, 5g Bacto-Peptone (Difco), 0.1g ferric phosphate, 30g agar, 750ml sea water and 250ml distilled water. After incubation for 4 days at 20°C, colonies developed on the plates were counted and the representative organisms were picked up.
It was shown that the numbers of bacteria in the intestinal contents of the fish samples varried from 10⁴ to 10⁸ per gram. Sixty strains were isolated in the present study, and all of them were identified as Vibrio spp.. Further, the vibrios were divided into ten groups on the basis of biochemical characteristics. The organisms belonging to Groups I, II and III accounted for 77 per cent of the total isolates. Almost all vibrios grew well at 25°C to 37°C, but failed at 5°C or 42°C. All the isolates failed to grow in the ordinary broth without salt, and grew well in the medium containing 3 per cent sodium chloride as well as sea water.