This study evaluated the impact of dietary supplementation bacteria, Lactobacillus plantarum and Lactobacillus bulgaricus isolated from the intestine of Barbus grypus on growth performance, survival and intestinal flora of common carp. For this purpose 480 common carp (average initial weight of 40 ± 6g) were randomly divided to 4 treatments (with three replications) and fed with diet containing 5×107 CFU/g L.plantarum (Group 1), L.bulgaricus (Group 2), Lactobacillus casei (Group3) and a diet without probiotic supplementation (As control group) for 60 days. To evaluate the persistent of the bacteria in digestive system, from the 60 th day to75 th day, experimental fish were fed with diet without probiotics (control). Results showed that Specific growth rate of fish fed diets containing Lactobacillus significantly higher compared with control group (p<0.05). Fish fed diets containing L.casei had significantly lower FCR than the control group on 60 th and 75 th of trial (p<0.05). The protein efficiency ratio and specific growth rate of fish fed the isolated bacteria at different times of trial was higher compared to fish fed than control diet. In general, results of intestinal micro flora assessment showed that Lactobacillus bacteria significantly increased in fish fed with dietary probiotic at 30 and 60 of trial (p<0.05) and groups 2 and 3 showed the greatest amount of Lactobacillus compared to the control group after 30 days of feeding. Theresults of this study showed that the addition of lactobacillus bacteria isolated from the intestines of Barbus grypus in the diet of common carp increased the beneficial micro flora population of intestinal microflora and ultimately improved growth performance and feed utilization
