Molecular Diagnosis of Vibrio spp. and It’s Bioremediation with Indigenous Probiotic (Streptococcus faecalis) in Prawn Farm

Abstract

Probiotics are gaining popularity as eco-friendly alternatives to antibiotics in improving prawn health and minimizing diseases. Present study was assessed to detect the pathogenic bacteria Vibrio spp. at molecular level and to examine the effect of indigenous probiotic, Streptococcus faecalis against Vibrio spp. on freshwater prawn Macrobrachium rosenbergii. Identification of pathogenic Vibrio spp. was confirmed by PCR, targeting the virA gene. An antagonistic effect of Streptococcus faecalis against Vibrio spp. was found significantly (P<0.05) at 8th and 12th hour of probiotic treatment in in-vitro and after 60 days of probiotic fortified diet treatment in in-vivo challenge tests. Dietary administration of probiotic significantly (P<0.05) increased the growth and digestive enzymes (protease and amylase) activity of Macrobrachium rosenbergii. This bacterium also improved immune system by augmenting total haemocyte count of freshwater prawn, although it was not significant (P>0.05) compared to control group. From the present study, it can be inferred that Streptococcus faecalis as a probiotic bacterium may be used as biological control agent against vibriosis in freshwater prawn aquaculture.