Effect of Watercress (Nasturtium officinale L.) powder on performance and immune response of broilers

This experiment was conducted to evaluate the effect of Watercress powder on performance and immune responses، by using 200 broilers. The brids were spilt into four groups and each group into five parts which include 10 brids. The levels of zero (N0)، 1 (N1)، 2 (N2) and 3 % (N3) powder of Watercress containing 82 mg/Kg quercetin were added to basal diet of each group from 4 to 42 day of old. To assay cellular immune responses، 0. 1 ml PHA-P (0. 2 mg/ml) was injected in the skin fold of wings at 16 d and thickness of skin were measured after 24 and 48 h. The humoral immune responses was estimated by means of injection of the 25% SRBC suspension (0. 1 ml) in the breast muscle at 8 and 22 d and the titers of IgG and IgM anti SRBC was determined by haemagglutination test at 21، 28، 35 and 42 d. The results showed that feed conversion ratio was lower in N3 (1. 63) than control (1. 74; P<0. 05). The titer of IgG was higher in N3 (6، 3. 8 and 2. 53، respectively) than control (4. 33، 2. 67 and 1. 87، respectively) at 28، 35 and 42 d (P<0. 05). Cell immune response was higher in N3 (0. 22) than control (0. 04) after 24 h from PHA-P injection (P<0. 05). The results concluded that the addition of the consecutive 3% Watercress powder to diet may improve performance and immune responses of broilers.