Effects of Different Levels of Artichoke (Cynara scolymus) on Growth Performance and Immune Responses of Broilers under Heat Stress

This experiment was undertaken to evaluate the effect of dietary level of artichoke (Cynara scolymus) on growth performance and immune response of broilers under heat stress (HS). Two hundred forty day-old broiler chicks (Ross, 308) were randomly assigned to one of four dietary treatments with four replicate pens per treatment (15 birds per pen) in a completely randomized design with a 2 × 4 factorial arrangement (4 treatment diets and 2 different temperatures rearing systems). Treatment diets were: 1) control diet, 2) and 3) control diet supplemented with 15 and 30 g artichoke, respectively and 4) control diet supplemented with 300 mg/kg vitamin E. Body weight (BW) and feed conversion ratio (FCR) were not influenced by dietary artichoke (P > 0.05). In the case of sheep red blood cells (SRBC), there were no significant differences be-tween treatments. However, the control group in HS condition showed lower titer for sheep red blood cells (SRBC) while group receiving 3 percent artichoke showed higher titer )P < 0.05). There was no significant difference between treatments for Newcastle antibody titer. Regarding lymphoid organs, the weights of bourse and spleen were similar, while liver weight differed between treatments. In this regard, chicks under HS in the control group had lower weight than the other groups. Lymphoid organ weights and antibody responses were significantly reduced under HS. These results indicated that HS severely reduced growth performance and immune response of broilers, whereas the immune response of broilers could be improved by dietary artichoke supplementation under HS.