Isolation and identification of Vibrio species that cause vibriosis in shrimp (Penaeus monodon ) larvae and its prevention/control using a locally produced probiotic

Abstract

Though Sri Lankan shrimp hatcheries use UV sterilized sea water, significant mortalities occur at different larval stages due to vibriosis, if antibiotics are not used to prevent/control it. The present study investigates the sources of contamination, to isolate and identify species of Vibrio and to find out whether vibriosis could be prevented /controlled by a locally produced probiotic containing Bacillus subtillis. Total Vibrio count in incoming water and in different culture facilities was determined, and species of Vibrio isolated from twenty randomly selected shrimp hatcheries were identified. Rearing tanks of two groups of experimental hatcheries were maintained with a probiotic at a concentration of 1× 106CFUml-1 Bacillus subtillis; larvae in one group (E1) were fed with disinfected Artemia nauplii and those in the other (E 2) were fed with non-disinfected Artemia nauplii. Rearing tanks in hatcheries of positive control group were maintained with antibiotics and tanks in negative control group did not receive any treatment; larvae in both controls were fed with non-disinfected Artemia nauplii.