There is an increased demand to identify nutritional tools which can promote gut health in food producing animals since the ban of antibiotic growth promoters. Therefore, the current study investigated the effects of wheat bran supplementation with or without butyrate producing Cl. butyricum on caecal microbiota composition of broiler chickens. In total, 384 male Ross 308 day-old chickens were divided into four dietary treatment groups using four replicate pens and 24 chickens per pen. A corn-soybean based control diet (C). wheat bran (WB), Clostridium butyricum supplemented (CLB, 25x109 CFU/kg), and WB+CLB diets were formulated and fed ad libitum. On day 37 of life, 2 chickens per pen were slaughtered and caecal chymus samples were taken for caecal pH, short-chain fatty acid composition and for caecal microbiota analyses. Samples from one pen were pooled and 16S rRNA gene targeted Illumina MiSeq sequencing was used for microbiota analysis. Production parameters were tracked during the experinental period. Neither Clostridium butyricum nor wheat bran supplementation affected production parameters, caecal pH or SCFA composition, but wheat bran supplementation increased the relative abundance of A. muciniphila in the chicken caecum. At the phylum level, the predominant phyla in all sampling groups were Bacteriodetes (57,5%-59,0%), Firmicutes (30,8%-37,2%), Verrucomicrobia (0,0%-5,9%) and Proteobacteria (0,5%-2%). As a conclusion, prebiotics may be used, not only in humans but also in chickens, for the promotion of the beneficial 4. muciniphila bacterium.