Monogastric

A monogastric organism has a simple single-chambered stomach, whereas ruminants have a four-chambered complex stomach. Examples of monogastric animals include omnivores such as humans, rats and pigs, carnivores such as dogs and cats, and herbivores such as Horses and rabbits. Herbivores with monogastric digestion can digest cellulose in their diet by way of symbiotic gut bacteria. However, their ability to extract energy from cellulose digestion is less efficient than in ruminants.^[1]

Herbivores digest cellulose via microbial fermentation (biochemistry). Monogastric herbivores who can digest cellulose nearly as well as ruminants are called hindgut fermenters, while ruminants are called foregut fermenters.^[2] These are subdivided into two groups based on the relative size of various digestive organs in relationship to the rest of the system: colonic fermenters tend to be larger species such as horses and rhinos, and cecal fermenters are smaller animals such as rabbits and rodents.^[3] The great apes (bonobos, chimpanzees, gorillas, and orangutans), in contrast to humans, derive significant amounts of phytanic acid from the hindgut fermentation of plant materials.^[4]

Monogastrics cannot digest the fiber molecule cellulose as efficiently as ruminants, though the ability to digest cellulose varies amongst species.^[1]

References

1. ^ ^{a b} Animal Structure & Function
2. ^ Hindgut versus Foregut Fermenters
3. ^ Grant, Kerrin. Adaptations in Herbivore Nutrition, July 30, 2010
4. ^ Watkins, P. A.; Moser, A. B.; Toomer, C. B.; Steinberg, S. J.; Moser, H. W.; Karaman, M. W.; Ramaswamy, K.; Siegmund, K. D. et al. (2010). "Identification of differences in human and great ape phytanic acid metabolism that could influence gene expression profiles and physiological functions". BMC Physiology 10: 19. doi:10.1186/1472-6793-10-19.  edit