This investigation was aimed to evaluate the effects of Silybum marianum seed, Thymus vulgaris, and Rosmarinus officinalis powders and their combination in alleviating the risks of aflatoxin B1 (AFB1) in young broiler chicks. One-day-old Ross 308 male broiler chickens were allocated to 6 experimental groups from d 1 to 21. The experimental dietary groups included: Negative control (NC) received the basal diet, Positive control (PC) containing 2 mg AFB1/kg diet; Positive control + 10 g/kg diet of Silybum marianum seed (SMS); Positive control + 10 g/kg diet of Thymus vulgaris (TV); Positive control + 5 g/kg diet of Rosmarinus officinalis (RO); Positive control + 10 g/kg diet of SMS + 10 g/kg diet of TV + 5 g/kg diet of RO as a blend of herbs (BH). There was no difference between feed intake and body weight gain among the experimental groups (P>0.05). In contrast, the feed conversion rate (FCR) in NC and SMS groups was lower than in other groups (P<0.05). Calcium levels and high-density lipoprotein cholesterol (HDL) were lower in serum samples, but the activity of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were higher in PC chickens (P<0.05). Increase in the thigh muscle malondialdehyde (MDA) in chickens fed AFB1 was significantly reduced in the NC, SMS, and BH chickens (P<0.05). Chickens of NC and SMS groups showed the highest response to respiratory burst of heterophil (NBT assay) and lymphocyte proliferation assays (MTT assay) (P<0.05). In conclusion, the addition of studied herbs, especially SMS, to the AFB1 contaminated diet could have a protective effect against aflatoxicosis in broiler chickens.
