There is little scientifically based information on nutrient requirements and efficiency of nutrient utilization by ratites. Nevertheless, successful feeding programs have been developed by using basic physiological and historical information available about ostriches and emus, combined with knowledge about the nutrient requirements of poultry and other species. The gastrointestinal tracts of the ostrich and emu differ greatly from each other, but both animals are considered to be monogastric herbivores, with an ability to utilize substantial amounts of dietary forage. In contrast to the digestive tract of chickens and turkeys, ostriches and emus have no crop in which to store ingested food. The intestinal tracts of these two ratites differ markedly.
Ostriches also possess relatively small ceca compared with emus.
J. of Zoo and Wildlife Med. Microscopic Anatomy of the Digestive System of the Chicken, Iowa State University Press, Ames, IA 50014. The ostrich has the ability to utilize a good portion of fibrous substances provided in their diets after the appropriate microbial population has been established in the intestines. Research findings on emu fiber digestion have been mixed indicating near 0 to as much as 45 percent fiber digestion with greatest digestion occurring as amounts of fiber consumed decrease. Ostriches and emus also seem to have the digestive enzymes and absorptive capacities needed to efficiently utilize dietary protein, fats, minerals, and vitamins.