Recent Advances and Perspectives on the Gastrointestinal Microbiota of Small Ruminants

Book excerpt: Ruminants are hoofed mammals with a unique digestive system that allows them to better create energy from fibrous plant material than other herbivores. Small ruminants (such as sheep and goats) play an important role in global food security and nutrition, as well as in the livelihoods of farmers and others along the food chain. Due to the unique digestive systems of ruminants, many major studies have focused on the effects of high-concentrate diets on rumen fermentation, ruminal acidosis, and their microbial properties and functions. Therefore, paying attention to the intestinal health of small ruminants during the rapid fattening stage has important implications for their health and productivity. Ruminants host a taxonomically diverse microbiota in their rumen, which is generally considered to be the most efficient natural fermentation system. Rumen microorganisms facilitate the degradation of otherwise indigestible plant fibres into absorbable compounds such as proteins and volatile fatty acids, the main source of energy and nutrition for ruminants. They are composed of a complex and dynamic assembly of bacteria, fungi, archaea, protozoa, and viruses. Diets and additives directly affect the number and viability of rumen microorganisms.