Effect of Different Levels of Silymarin (Silybum marianum) on Growth Rate, Carcass Variables and Liver Morphology of Broiler Chickens Contaminated with Aflatoxin B1

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 (P1 alone did not affect thigh, back, neck, wings, heart, legs and spleen weights. Increasing the level of SMS in the diet alone or in combination with AFB1 resulted in significant changes in the weights of carcass and internal organs. Liver of birds fed diets containing AFB1 showed abnormal signs including enlargement, yellowish, friable and rounded shape. Liver of other treatments did not show any abnormal signs. In conclusion, these findings suggest that silymarin might be used in chickens to prevent the effects of AFB1 in contaminated feed.