Effect of Three Immunostimulants on Some of Indicators of Broilersʹ Immune Response

This study was conducted to determine the effect of Echinacea purpura, levamisole and vitamin E on humoral and cell-mediated immunity of broilers. Total of 200 one-day-old male broiler chickens (Ross 308), were randomly distributed to experimental groups included control, vitamin E (150mg/kg diet), 0.1% aqueous Echinacea, levamisole (15 mg/kg BW). Vaccination against Newcastle disease (ND) and avian influenza (AI; H9N2) were performed. The hemagglutination inhibition (HI) titers against both vaccines were determined on serum samples at days 21 and 42. Chicks were injected into breast muscle with sheep red blood cells (SRBC) at 14 and 35 days. Blood samples were drawn at 1 days after the first and the second injections. The antibody levels against SRBC were measured by hemagglutination test. The cell-mediated immunity was determined via phytohemagglutinin (PHA) and dinitrochlorobenzene (DNCB). Antibody titers against AI, ND, total anti-SRBC at 21 day and IgM at 21 and 42 days of age were not affected by the treatments (P>0.05). Although cell-mediated immune responses by DNCB (31 day) and PHA (42 day), total anti-SRBC antibody, IgG and IgG/IgM ratio (42 day) (P<0.01), IgG and IgG/IgM ratio (21 day) (P<0.05), were affected by some of the used treatments. In conclusion, taking into account the public urge in withdrawn of chemicals, interest in nutraceuticals in animal production and observed results, use of Echinacea extract and vitamin E as immunomodulator feed adjuncts needs further study.