Addition of 4.0 g/kg FOS to the basal diet significantly increased ADG of broilers (Table 2). Addition of 2.0 or 8.0 g/kg FOS had no effect on ADG. The feed-to-gain ratios were decreased by 0.12 (P < 0.05) and 0.20 units (P < 0.05) for the birds fed diets with 2.0 and 4.0 g/kg FOS versus the control, respectively. However, feed intake was unaffected by dietary treatments