The purpose of this investigation was to evaluate the effect of a dietary supplement (MirigenTM),a fungal cell wall derivative product,as a new generation alternative to antibiotics,on the growth and the innate and adaptive immune functions in broilers from birth to 45 d of age. Newborn chicken were randomly assigned to one of three groups:G1 (n=150) controls no supplement fed;G2 (n=150) is fed with dietary supplement at a designed regular dose (0.5%,weight of additive to food);G3 (n=150) is fed with dietary supplement at double doses (1%). All three groups were housed in the same conditions. Body weight and blood were taken on day 1,14,28 and 45. Medications used and costs/treatment were recorded for each group. The whole blood was used to purify heterophils for reactive oxygen species (ROS) generation and E coli killing abilities examination assays,and the serum samples were preserved in freezer for enzyme linked immunosorbent assays (ELISAs) to determine concentration of macrophage inflammatory protein-1β(MIP-1β),CD4/CD8,interferon-γ(IFN-γ), and titers of antibody against Newcastle disease virus (NDV). Group differences were analyzed using analysis of variance (ANOVA) algorithm (S-Plus). There was no significant birth weight difference in three groups. Af-ter 45 d growth,the dietary supplement treated groups had significantly higher body weight gain (BWG) with lower mortality rate if compared to the untreated control group (P