Variations in the Intestinal Microflora of Tilapia Reared in Fresh and Sea Water

Abstract

The composition and characteristics of microflora isolated from the intestine of Tilapia zillii were determined for fishes reared in fresh and sea water. Intestinal microflora of fresh or sea water fishes consisted mainly of Aeromonas or Vibrio and Aeromonas respectively; while the predominant bacteria obtained from fresh or sea water samples were Flavobacterium or Pseudomonas, respectively. The intestinal bacteria isolated from sea water fish were slightly halophilic and lower in the percentage of casein hydrolytic strains compared with those from fresh water fish. Chtin hydrolytic bacteria were abundant in the intestines of both fresh and sea water fishes in contrast with water samples. The change of intestinal microflora of Tilapia zillii happened for a fairly short term depending on the change of environment. © 1980, The Japanese Society of Fisheries Science. All rights reserved.