Astragalus polysaccharide and sulfated epimedium polysaccharide synergistically resist the immunosuppression

► The immunoenhancement of APS-sEPS was observed in immunosuppressed model chicken. ► APS-sEPS could promote T-lymphocyte proliferation and raise serum antibody titers. ► APS-sEPS could enhance serum IFN-γ, IL-2, IgG and IgM level. ► APS and sEPS could synergistically resist the immunosuppression. ► APS-sEPS was an effective immunopotentiator.