DIGESTIBILITY OF PHYTIN PHOSPHORUS AND INTESTINAL PHYTASE IN DAIRY COWS AND SHEEP

The digestive mechanisms of phytin phosphorus have been studied in dairy cows and sheep. The summary of the results is as follows : 1. Phytin phosphorus of cereal bran has been digested completely in the gastrointestine of sheep. The digestibility is not altered in the heat-treated cereal bran whose own enzyme is inactivated. 2. High potential activity of a phytase was found in the content of the small intestine, but in the contents of the rumen, abomasum, cecum and colon the enzyme exerted only a feeble action, if any, on the substrate. 3. The optimum pH of the enzyme is about 6.3,optimum temperature 55℃. The enzyme is activated by magnesium ion at an optimum concentration of 0.001M, inactivated by sodium cyanide, mercuric chloride, and calcium chloride, and not effected by potassium oxalate and sodium flouride at a concentration of 0.01M. 4. The pH values of the contents of the upper small intestine in dairy cow and sheep range 6.5∿7.1. These values are most near to the optimum pH of the intestinal phytase among the contents of other parts of the gastrointestine examined