One of the most drawbacks of antibiotic usage in the poultry diet might be lack or negative effects on humoral immunityof the birds. As suggested by Xu et al. (2003), lactic acid bacteria may promote the immunity of the birds through modulatingintestine environment while antimicrobial properties of antibiotics such as flavophospholipol against lactic acid bacteria(data not shown) may lead to inability of antibiotics to improve immunity responses. Therefore, substitution of antibioticsby medicinal herbs not only exert antimicrobial properties, but also may help to improve the immunological responses. Inaddition, medicinal herbs along with antimicrobial effects play as natural antioxidant with potential benefits to increasemeat quality (Velasco and Williams, 2011).