Microbial symbiotic digestion
Reindeer are foregut fermenters whose digestion of plants depends on a symbiotic association with a complex of microbiota resident within their rumen. We study the function of this microbial ecosystem in relation to large seasonal variations in diet composition, biomass and quality. Presently, focus is directed towards how different diets affect functions of the gut microbial ecosystem in relation to methane emission in arctic herbivores. In cattle and sheep, enteric methane emission produced by rumen methanogenic Archaea represents a loss of up to 15% of their energy intake, and is also an important source of this greenhouse gas. In winter, reindeer eat lichens which are rich in polysaccharides but which also contain phenolic tannins that have the potential to depress rumen methane production. Thus, recent studies in our group demonstrate that methane emission from reindeer fed a mixed lichen diet is lower than when fed a grass-based diet. We will study possible feed-induced effects on methanogenic processes in the rumen microbial ecosystem, at the gut microbiome level. For comparative purposes we also study similar mechanisms in non-arctic herbivores (sheep) and in an avian arctic herbivore, the Svalbard ptarmigan.
Contact person: Monica Alterskjær Sundset.