Fisiologia dels cecs de pollastre

Resum

The morphology and physiology of the chicken cecum is reviewed. The large intestine of the chicken is formed by the rectum and the cloaca, and two well developed ceca, which are two blind sacs, tubular in shape, that originate at the junction of the small intestine and the rectum.
Light microscopy observation of the epithelium demonstrates that the proximal region has well developed villi, in contrast to distal cecum where they are either small or absent. Information hitherto available on the physiological mechanisms underlying the filling and emptying of the cecurn has been revised, and it is particularly worthy of note that cecum contents may have both ileal and rectal origins.
Several functions have been suggested for the cecum of the chicken but much remains to be discovered about its real physiological significance. There is evidence that proteins and complex carbohydrates can be partially digested in the ceca. It is also claimed that the cecum is the site of production of significant amounts of free volatile fatty acids and vitamins, among other compounds. Several authors have observed absorption of electrolytes and water in the cecum. Urine can enter the ceca by a retrograde flux, which suggests that the cecal epithelium plays a role in osmoregulation in fowl, a function which may be of special relevance in dehydrated animals.
Recent reports on the sugar-transport characteristics of the chicken cecum indicate that the epithelium of the proximal area possesses an active transport system as efficient as that described in the small intestine. This raises the possibility that ceca are significant in chicken nutrition, since sugar uptake can occur both during cecal filling and emptying.
The physiological role of chicken ceca is not well understood. However, it has been shown that ceca are not essential for animal survival, at least in environmental conditions allowing normal feeding and hydration.