A study was undertaken to evaluate the effects of Neoxyval (antimicrobial growth promoter (AGP)), TechnoMos (prebiotic), Galli Pro (probiotic) and a mixture of TechnoMos and Galli Pro (symbiotic) on growth performance, carcass yield, histomorphology and intestinal bacterial counts in broilers (0 d to 42 d). Two hundred day-old Ross (308) broilers were allocated to five experimental treatments: T1 = control (CONT), T2 = Ti + Neoxyval, T3 = Ti + Gallipro, T4 = T1+ TechnoMos and T5 = T1+ Gallipro+ TechnoMos. The results revealed that birds that received T2, T4 and T3 gained more weight and converted feed more efficiently than those in Ti and T5. Longer ileal villi (492.9 mu m) were recorded in birds that received T4 compared with Ti (424.7 mu m) and T2 (439.9 mu m). Conversely, jejunal villi length and width were not influenced by treatment. T3 eliminated Clostridium perfringens from the ileum, but not from the caecum. Generally, birds that received T3 and T5 performed similar to the AGP group, T2. The results from this study indicated that the probiotic (T3) and prebiotic (T4) used in this trial could serve as alternatives to AGP (T2). Enhancement in the performance of broilers could be explained partially by improvement in intestinal morphology and microbial balance associated with modulation of intestinal nnicroflora and inhibition of pathogens.