Absorption of Calcium and Phosphorus along the Gastrointestinal Tract of the Laying Fowl as Influenced by Dietary Calcium and Egg Shell Formation

Abstract

The apparent absorption of calcium, phosphorus and total dry matter along the gastrointestinal tract of the laying hen, was followed using yttrium-91 as a non-absorbed tracer. Percentage calcium and phosphorus absorption appeared to be greater in the proximal parts of the intestine than in the distal parts. This difference was smaller for total dry matter. Percentage calcium absorption was not significantly influenced by its dietary level, nor did the latter influence the absorption of dry matter. Percentage absorption of phosphorus was, however, depressed by the higher dietary calcium level. Egg shell deposition was associated with increased calcium and to a smaller degree, phosphorus absorption. It did not influence dry matter absorption. A heavy endogenous phosphorus excretion was observed in the duodenum.