Effects of astragalus polysaccharides on immunologic function of erythrocyte in chickens infected with infectious bursa disease virus

160 Haline white chickens at 25 days old, negative for antibody to infectious bursa disease virus (IBDV), were randomly allocated into four groups. Chickens in groups 2–4 were infected with 0.3 ml IBDV at 26 days old. Chickens in groups 3 and 4 were injected respectively with 5 and 10 mg astragalus polysaccharide (APS) for 6 consecutive days from the first day of infection. At 21, 29, 32, 35 and 38 days old, the blood samples were taken from heart, and erythrocyte-C_3b receptor rosette rate (E-C_3bRR), erythrocyte-C_3b immune complex rosette rate (E-ICRR), erythrocyte rosette forming enhancing rate (ERER) and erythrocyte rosette forming inhibitory rate (ERIR) were measured. The results showed that E-C_3bRR and ERER significantly declined in chicken infected with IBDV (p < 0.01); E-C_3bRR, E-ICRR and ERER in groups 3 and 4 treated with APS were higher than that in groups 1 and 2 (p < 0.01), the ERIR in groups 3 and 4 is similar to that in group 1. The results suggest that the immunological function of chicken erythrocytes declines after infected with IBDV and APS obviously enhances the immunological function of chicken erythrocytes.