This study was conducted to investigate the effects of protexin probiotic and aquablend avian antibody on the performance and immune system of broilers. In this experiment, 320 1-day-old male broiler chicks of the Ross 308, with 5 treatments and 4 replications in a completely randomized design were distributed in experimental units (cages). The treatments include: control (C), protexin (P1), protexin (P2) with double there commended dose, aquablend (A1) and aquablend (A2) aquablend twice there commended amount. The results showed that protexin probiotic and aquablend avian antibody in different doses had no significant effects on average weight gain and feed consumption of broilers at different week (P>0.05). A significant difference between treatments was observed in feed conversion ratio at the second and fifth weeks (P<0.05). Consumption protexin probiotic and aquablend avian antibody with different doses has significant effect on the relative weight of carcasses (P<0.01). Consumption protexin probiotic and aquablend avian antibody with different doses had no significant effect on antibody titers produced in primary and secondary challenge with sheep red blood cells (P>0.05). According to results of this research, it seems that the using of protexin probiotic and aquablend avian antibody has not importance effect on improving the performance of broilers except for carcass weight. پرونده مقاله