Intestinal absorption and secretion of total and lipid phosphorus in adult sheep fed chopped meadow hay

Summary. The flow of total (PT) and lipid (Ppd phosphorus was measured in adult sheep fed meadow hay and fitted with Ivan-Johnston reentrant cannulas in the duodenum (just posterior to the entry of the common bile and pancreatic duct) and in the terminal ileum. The pattern of plasma, duodenal and ileal PT and PL specific radioactivity was also studied. The considerable total and lipid P secretion observed between the mouth and the duodenal cannula could be accounted for by salivary and biliary secretions, respectively. This secretion was followed by high absorption in the small intestine and less in the large intestine. A comparison of P specific radioactivities showed that the selective PL reabsorption occurring in the small intestine could be due to the existence of an entero-hepatic cycle of biliary phospholipids. Introduction. Ruminant utilization of minerals can be studied by a wide range of methods. When phosphorus (P) is investigated, these methods namely include regression and radioisotopic procedures for estimating endogenous loss and true availability