Isolation and identification of Vibrio species from Macrobrachium rosenbergii cultured in selected five reservoirs in Uva and Southern provinces in Sri Lanka

Abstract

Macrobrachium rosenbergii (Giant Freshwater Prawn/GFP), residents in the tropical freshwaters adjacent to brackish water areas are more popular among the culture of crustaceans due to their rich taste and profitability. M. rosenbergii culture is now an emerging sector in Culture-Based Fishery in perennial and non-perennial reservoirs, Sri Lanka. Though it is profitable business, at present, M. rosenbergii production in Sri Lanka is low in both quality and quantity. Most devastating threat is the presence of disease-causing agents and among the diseases causing agent, microbes play an important role. Bacteria, especially the vibrios have a significant impact on M. rosenbergii. Most of the studies have identified disease causative bacteria on GFP with frequently encountered Vibrio species. Vibrios are Gram-negative, rod-shaped, facultative anaerobes, (family Vibrionaceae), abundant in warm, brackish water and they lead to the devastating disease; vibriosis. Even though there are non-pathogenic vibrios, about 12 species cause infections in humans by consumption of Vibrio contaminated seafood, water, and by wound exposing to water containing Vibrios, hence the zoonotic vibriosis. Among the diverse disease out come in aquaculture species by vibrios, luminous vibriosis, fouling disease, blackening of gills, brown spots and white muscle disease are some significant infections in prawn culture. Though there are reports at global level, there is hardly any report on the vibrios associated with Macrobrachium rosenbergii in Sri Lankan reservoirs. Hence this study aimed to enumerate total bacteria and vibrios present in Macrobrachium rosenbergii; collected from five reservoirs, in Uva and Sothern provinces and also to isolate and identify Vibrio species associated with M. rosenbergi. Further studied the sensitivity of the Vibrio isolates to commonly used antibiotics.