Species of Vibrio isolated from hepatopancreas, haemolymph and digestive tract of a population of healthy juvenile Penaeus vannamei

The number and species of Vibrio spp. bacteria that may be present in normal healthy Penaeus vannamei juveniles are described. The hepatopancreas, stomach, intestine and haemolymph of P. vannamei juveniles were sampled. All three areas of the digestive tract contained a diverse population of Vibrio spp. but the haemolymph contained bacteria in only 14.3% of the animals sampled, with counts of Vibrio spp. ranging from 2 X 10(2) to 3 X 10(3) CFU/ml. The Vibrio spp. isolated from the digestive tract included both sucrose and non-sucrose fermenters whereas the haemolymph contained only non-sucrose fermenters. The findings of this study would suggest that there may be a wide range of Vibrio spp. in the hepatopancreas of normal healthy P. vannamei. (C) 1998 Elsevier Science B.V. All rights reserved.