EN
The effects of genetically modified (GM) soybean meal (SBM) and maize on the diversity and activity of microbiota inhabiting terminal gut segments in broiler chickens Were studied. Eight diets were prepared, based on conventional or GM SBM combined with maize cvs Clarica or PR39 F58, or their isogenic MON 810 counterparts cvs Bacilla or PR39 F56. Diets were fed from age 1 to 28 days to 144 Ross broilers, allocated to eight groups of 18 birds each. The microbiota was analysed by terminal restriction fragment length polymorphism (T-RFLP) analysis and its activity was measured. In the ileum and caecum of all groups, members representing the orders Clostridiales, Lactobacillales and Selenomonadales were present, accompanied by Bifidobacteriales in the caecum. The diversity of the order Lactobacillales in the ileum and caecum of birds fed GM maize was reduced, while that of Lactobacillales in the ileum and Bifidobacteriales in the caecum of birds fed GM SBM was higher compared with conventional maize and SBM. The use of GM and conventional maize and SBM did not affect the activity of microbiota measured as bacterial enzyme activity and the concentration of short-chain fatty acids in the ileal and caecal digesta. The GM maize did not change resistance of E.