monogastric

Monogastric is a term used in animal nutrition and physiology to describe animals that possess a single-chambered stomach. This contrasts with ruminants, such as cattle and sheep, which have a multi-chamber foregut (rumen, reticulum, omasum, abomasum) that ferments ingested feed before digestion. In monogastrics, digestion begins in the stomach, where acid and enzymes (notably hydrochloric acid and pepsin) denature and start to digest proteins. The stomach also churns the contents, producing a semi-fluid chyme that passes to the small intestine through the pyloric sphincter. In the small intestine, pancreatic enzymes and bile further digest nutrients, and intestinal absorption takes place through the mucosa, distributing amino acids, simple sugars, fatty acids, vitamins, and minerals to the bloodstream. The extent of microbial fermentation is limited compared with ruminants, though some hindgut fermentation can occur in species with enlarged ceca or colon.

Common examples of monogastric animals include humans, pigs, dogs, and cats. Monogastric systems are generally well adapted to diets rich in readily digestible carbohydrates and proteins, but they are less efficient at extracting energy from fibrous plant material like cellulose unless specialized hindgut or microbial processes contribute.

In agriculture and pet nutrition, understanding monogastric digestion informs feed formulation, processing, and welfare. Diets are designed to optimize digestibility, stomach pH, and transit time, with attention to energy density, protein quality, and essential micronutrients.