Use of indigenous beneficial bacteria (Lactobacillus spp.) as probiotics in shrimp (Penaeus monodon) aquaculture

The present study was conducted to study in-vitro the antagonistic effect of Lactobacillus spp. against the pathogenic bacterial vibrio harveyi on shrimp. For this purpose, shrimp samples were collected from three different Ghers at Batiaghata upazilla, Khulna. Gills and intestines were taken out from the samples to identify the load of Lactobacillus spp. and Vibrio spp. The results revealed that the load of Lactobacillus spp. was found more than Vibrio spp. both in gills and intestines; the gills also contained higher load of Vibrio spp. than in the intestines. V. harveyi was separated from the isolated Vibrio spp. with different types of biochemical tests: Gram stain, Motility test, Indole test, VP test, MR test, Arginine dihydrolase, Salt tolerance test, growth at different temperature ranges and colony color on TCBS agar media. The isolated V. harveyi was subjected for in-vitro test. In in-vitro challenge test, the potential antagonistic effect of Lactobacillus spp. against V. harveyi was gradually obtained at 0, 4th, 8th, 12th hour of treatments. Interesting finding was that, with the time, the load of V. harveyi was reduced gradually and the lowest load was obtained after 12 hours of probiotic inoculation. The present study revealed an excellent in-vitro antagonistic probiotic effect of Lactobacillus spp. on V. harveyi. Therefore the result suggested that probiotic treatment might be an effective alternative to the use of antibiotics in treatments of bacterial diseases in shrimp aquaculture.Res. Agric., Livest. Fish.5(1): 127-135, April 2018