In the present study was Vibriornspecies from wild marine shrimp, Penaeusrnmonodon and to study its effect on the probiotic feed supplementedrnorganism, when artificially in infected. Biochemical changes during infectionrnof Vibrio parahamolyticus wasrnevaluated by studying the Superoxide dismutase activity and catalase activityrnafter infection. The superoxide dismutase activity and catalase activity inrnhepatopancreas was estimated in prawns from all the three feed groups. Therernwas significant variation in the SOD activity and catalase activity in allrnthree groups, after 30 days of feeding, uniformly they recorded gain in thernactivity. The SOD activity was 2.65 in control animals, 5.8 in B. coagulans supplemented animals, andrn4.4 in B. firmus supplemented animalsrnand catalase activity was 15.8 in control animals, 29.0 in B. coagulans supplemented animals, and 26.3 in B. firmus supplemented animals. The presence of this B.rncoagulans and B. firmusrncould protect the aquatic animals against the infection by pathogenic bacteriarnand might be applied as good probiotics in aquaculture.