Chapter 4 Microbial ecology of the digestive tract in reindeer: seasonal changes

Publisher Summary This chapter reviews the literature on the gastrointestinal microbiota in two different sub-species of reindeer: Svalbard reindeer and Norwegian reindeer. Digestion in reindeer depends on a highly active anaerobic symbiotic rumen bacterial population, ciliated protozoa, and anaerobic fungi, compartmentalized in the rumen fluid, plant solid digesta, and epithelial mucosa. Reindeer, unlike domestic ruminants, are highly adaptable mixed feeders. Different gastrointestinal microfloras have evolved in the two reindeer populations studied. The gastrointestinal tract of newborn ruminants is colonized from birth. The rumen in reindeer contains complex consortia of microorganisms that live in a mutualistic relationship with the host. The dominant populations of microorganisms consist of anaerobic bacteria, methanogens, ciliates, and anaerobic fungi compartmentalized into different populations associated with the rumen fluid, feed particles, and the rumen wall. Microbial enzymatic breakdown of complex plant components in the rumen results in fermentation products such as short chain fatty acids (SCFA), CO 2 and CH 4 .