Effect of Dietary Bone Powders on Calcium Metabolism in Rats

Abstract

The effects of dietary bone powders on mineral and bone metabolism were studied in growing male rats. Three kinds of bone powders were prepared; freeze-dried (F) , boiled and air-dried (B) ; and ashed (A) . In a control diet, CaCO₃ and CaHPO₄ ・ 2H₂O were supplied to adjust calcium and phosphorus contents. Magnesium content was 18% higher in diets consisting of bone powders than in the control diet, because of relatively high content of Mg in bone powders. Each diet was fed to 8 rats of each group for 21 days. Five days before the end of the feeding trial, mineral balance was examined. The group fed diet A was lower than the other groups in Ca apparent absorption, Ca retention, and Ca content and specific gravity of tibia. On the other hand, there were no significant differences in these parameters among the groups other than group A. The ingestion of each bone powder increased apparent absorption and retention of Mg. These results indicate that Ca availability in the ashed bone powder is lower than in the bone powders without ashing and the inorganic Ca source. It is possible that Mg in bone powders is of a high absorbability.