Collectively, synergy between individual bioactive compounds in M. oleifera leaves may affect broad aspects of physiology, their ultimate objective being positive interaction with the biochemistry of the body ( Maiga et al., 2005, Mbikay, 2012 and Wallace et al., 2010). In earnest, the effect on growth performance may not be consistent, for instance, in a number of cases where plant extracts have been used, FI and FCR were not changed, although a positive effect on BW, BWG, organ weight and/or energy utilization was reported (Wallace et al., 2010). In another study, Lee et al. (2003b) observed that supplementation of female broiler chickens diets with thymol and cinnamaldehyde had no positive effects on growth performance or macronutrient digestibility.