Changes in the composition of Vibrio communities in pond water during tiger shrimp (Penaeus monodon) cultivation and in the hepatopancreas of healthy and diseased shrimp

Two batches of shrimp were cultivated in a total of 4 culture ponds from March 28 to June 13, and July 17 to September 11, 1997. Vibrio spp. were isolated from the pond water and the hepatopancreas of healthy and diseased shrimp using thiosulfate-citrate-bile salt-sucrose agar plate, and then identified using fatty acid methyl ester (FAME) analysis. In each culture pond, decreases in the diversity of the Vibrio community were observed prior to outbreaks of vibriosis; FAME analysis suggested that in diseased pond water (i.e., water from a pond in which there had been an outbreak of disease) and the hepatopancreas of diseased shrimp, V.furnissii was the major component of the Vibrio community. However, since identification confidence levels were too low (less than or equal to 0.500), the identity of 48 randomly selected putative V.furnissii was further checked using the Biolog system. Of these, 27 were identified as V. harveyi/V. carchariae, six as V. parahaemolyticus, five as V. anguillarum, four as V. alginolyticus, four as V. vulnificus, and two as V. damsela, the majority of which species are known to be associated with diseased shrimp. Similar results were also found for Vibrio communities in the hepatopancreas of diseased shrimps, with 68.2% of the isolated vibrios eventually identified as V. harveyi/V. carchariae. (C) 1999 Elsevier Science B.V. All rights reserved.