Abstract Article history:

This experiment was conducted to evaluate the ability of Silybum marianum seeds (SMS) on performance, carcass variables, and liver morphology of the broiler chickens contaminated with aflatoxin B1 (AFB1). A total of 216 broiler chicks (Ross 308) were used. Birds were randomly assigned to nine treatment groups, with four replicates and six birds in each replicate. Chickens were reared on litter from 1 to 35 days of age. Treatments were (AFB1) in three levels (Zero, 250 and 500 ppb) and SMS in three levels (Zero, 0.5 and 1.0 percent) using factorial experiment based on completely randomized design. Feed intake at the end of the three weeks did not significantly change in comparison with the control group. With the increase in the level of (AFB1) in the diet, feed intake and body weight gain were decreased compared with the control group in week 4. Feed conversion ratio was not influenced by the treatments. In diets containing AFB1, breast muscle, carcass ratio, abdominal fat and bursal gland weight were significantly decreased (P<0.05), whereas the relative weight of the liver, pancreas, gizzard, proventriculus and ful