The avian cecum: Update and motility review

The avian cecum is a blind-ended sac that extends from the proximal end of the colon. Ceca may be of several different histological types; they range in size from large and paired to very small and single, or they may be completely absent. Cecal types and sizes are summarized herein by taxonomic group. The intestinal type is best known; it may contain fluid, food particles, microorganisms, and substances produced by the ceca. Ceca may serve as the site for several different functions, especially digestion of small food particles, absorption of nutrients, production of immunoglobulins and antibodies, microbial action of beneficial and pathogenic organisms, utilization and absorption of water, and metabolism of uric acid into amino acids. Ceca in turkeys, chickens, and other galliforms have active motility that stirs and periodically evacuates the luminal contents. Contractions of the cecal wall propagate in either direction, with the majority being toward the cecal tip and most numerous when the ceca are filling with digesta. Propagation velocity of the contractions is affected by the presence or absence of food in the lumen. Cecal mixing contractions do not seem to be related to ileal motility. J. Exp. Zool. 283:441–447, 1999.