Ninety eight male, mixed breed weaner rabbits were used in a 70 day feeding trial to study the performance, apparent nutrient digestibility, caecal fermentation, ileal mor- phology and caecal microflora of growing rabbits fed diets containing Prediococcus acidilactis (1 10 10 cfu/g; 0.5 g/kg), Bacillus cereus (1 10 9 cfu/g; 0.5 g/kg), mannan oligosaccharides (MOS; 1 g/kg), arabinoxylans oligosaccharides (AX; 1 g/kg), oxytetracy- cline (1 g/kg), or synbiotics (TGI; 1 g/kg). A basal diet containing no feed additive was formulated. There were 14 rabbits per treatment. Rabbits fed diets containing MOS had the highest (P o 0.05) final live weight and weight gain. Dietary inclusion of prebiotics (MOS, AX) resulted in higher (P o 0.05) weight gains and improved feed to gain ratios. Rabbits fed diets containing MOS showed the highest (P o 0.05) while those fed diets containing probiotics (Prediococcus acidilactis, Bacillus cereus) had the least (P o0.05) caecal total volatile fatty acid (VFA) concentration. Rabbits fed diets containing prebiotics (MOS, AX) had longer ileal villi than groups fed with other treatments (P o 0.05). Inclusion of various additives showed reduced caecal coliform counts. The lowest (P o 0.05) lactobacillus count was obtained in the caecal content of rabbits fed diets containing MOS. Poor growth response was obtained with rabbits fed diets containing Prediococcus acidilactis or Bacillus cereus while inclusion of prebiotics in growing rabbits resulted in improved growth and gut morphology. Rabbits fed diet containing MOS showed the highest overall final live weight, weight gain, total VFA concentration and reduced caecal lactobacillus count.