Effect of different levels of silymarin on performance, carcass characteristics and antioxidant status in broiler chickens

In order to investigate the effect of different levels of silymarin (0، 100 and 200 mg/kg diet) on performance، carcass characteristics، blood parameters and antioxidant status، 120 day old chicks were assigned to 3 treatments with four replicates and 10 birds in each in a completely randomized design. Results showed supplementation of 200 mg silymarin significantly decreased the body weight gain (BWG) in starter (P<0. 05) and whole period of experiment (P<0. 01) and significantly increased feed conversion ratio at starter (P<0. 05)، grower (P<0. 05) and total rearing periods (P 0. 01). Also، addition of 100 mg silymarin significantly increased the carcass relative weight (P<0. 01) and supplementation of 200 mg silymarin significantly increased the breast relative weight (P<0. 05). Furthermore، 200 mg silymarin significantly increased the malondialdehyde and heterophil/ lymphocyte ratio and significantly decreased superoxide dismutase (P<0. 05). These results showed that supplementation of silymarin in diet under normal condition، improved the carcass and breast relative weight، but no had effect on bird’s oxidative status.