Synbiotics refer to nutritional supplements combining probiotics and prebiotics in a form of synergism, hence synbiotics, enhancing their isolated beneficial effects. The aim of current study is evaluating effects of different levels of Immunogen with Lactobacillus casei PTCC 1608 on some digestive enzymes activities of common carp fish (Cyprinuscarpio). This experiment has been carried out in five treatment (each with 3 replicate), including 0.5 (A), 1(B), 1.5(C)percent Immunogen with Lactobacillus casei5×107 cfu g_1 per gr diet,only Lactobacillus casei5×107 cfu g_1 (D) per gr diet and control € with non-synbiotic diet. 300 fish with average weight of 65±5 gr distributed in 12 tank (20ind/300 lit tank), fed experimental diet during11 weeks. To analyze the activity of digestive enzymes, on Days 0, 30 and 60 after probiotic feeding and 15 day after treatment cessation, the fish were starved for 24 h and take 3 fish per replicate and the three are taken randomly. The results showed that synbiotic could significantly the digestive enzymes activities assay demonstrated trypsine of α-amylase, lipase and alkaline phosphatase of synbiotic groups considerably was higher than control (p<0.05). This study indicated different levels of synbiotic have capability to enhance probiotic substitution, digestive enzyme activity lead to digestive system efficiency and finally raising growth. It seems this symbiotic at 1% Imnogene with Lactobacillus casei could select as a good diet supplement on common carp culture.