Effect of purple coneflower (Echinacea purpurea) extract on the performance and cellular and humoral immune responses of broilers under immunosuppressive condition

The experiment was conducted by using of 240 chicks to determine the effect of purple coneflower extract on the performance and immune responses under immunosuppressive condition. The extract of purple coneflower was added in the levels of 0 (E0), 1 (E1) and 2.5 ml (E2.5) to drinking water from 6 to 42 d. At 14, 15, 16, 34, 36, 38 and 40 d in each level of purple coneflower, half of chicks were treated by 9.9 mg/kg oral cyclosporine (C+) and other chicks were not treated (C-). The treatments were E0C-, E0C+, E1C-, E1C+, E2.5C-, E2.5C+. Cellular immune responses were assayed by injection of 0.1 ml Phytohaemagglutinin-P (PHA-P) (0.2 mg/ml) in the skin fold of wings at 16 d and thickness of skin were measured after 24 and 48h. To investigate humoral immune responses a 25% SRBC suspension (0.1 ml) were injected in the breast muscle at 33 d and titers IgG and IgM anti SRBC was determined by haemagglutination test at 34, 36, 38 and 40 d. Results indicated that the feed conversion ratio was lower for 1 ml (1.49) purple coneflower than control (1.62) purple coneflower (P2.5C+ thanE0C+ andE1C+ but it was lower thanE1C- andE2.5C- (P<0.05). Therefore, adding 2.5ml/l purple coneflower extract to drinking water improve cellular and humoral immune responses under immunosuppressive condition.