Effects of potential inhibitors of methane formation on the microbial community in the rumen and long-term effects on the methane release of sheep

Methane is a by-product of microbial fermentation under anaerobic condition such as it occurs in the rumen of ruminants. A reduction in methane production can be achieved by the supplementation of substances which bind the released hydrogen or have antibiotic properties. This affects the microbial fermentation and, consequently, the host animals. The aim of this project was to identify the potential of monensin (antibiotic) and several tannins (secondary plants metabolites) to reduce methane formation in ruminants and effects on ruminal fermentation. Following batch-culture studies according to the Hohenheim Gas Test longer-term studies are performed with a rumen simulation system (Rusitec). The evaluation of substances is based on the maximum reduction in methane production at unchanged total gas production. The degradation of nutrients, the production of short-chain fatty acids and microbial protein synthesis are quantified. Based on the results of these in vitro studies, respiration experiments over several months are conducted with sheep to examine long-term effect of selected substances on methane production.