Breaking-Properties and Ash Contents of the Femur of Growing Rat Fed a Low Calcium Diet

The study has been made to find the effects of a low calcium diet on the bone of growing rats by checking ash contents and breaking properties of the femur. Wistar-strain male rats were divided on weanling into groups I, II and III and were fed a control diet (Ca, 0.47%; P, 0.3%) for 5, 15 and 33 days respectively. Thereafter half of rats of each group were fed a low calcium diet (Ca, 0.003%; P, 0.3%) instead of the control diet for 30 days, and were compared with the other half which were kept on the control diet for the same period. The results are as follows: 1) Weight gain during the last 10 days were considerably less in the rats fed the low calcium diet (group I and II). 2) The serum calcium level decreased only in rats of group I that were fed the low calcium diet. 3) Decrease in the bone density was recognized by the X-ray in the rats fed the low calcium diet; most remarkable in the rats of group I. 4) The contents of ash, calcium and phosphorus per dry weight of bone decreased in the rats of groups I and II on feeding the low calcium diet, more remarkable in the rats of group I. 5) A relationship between dietary calcium contents and susceptibility to bone fracture was confirmed by determination by Dynagraph of breaking-strength, breaking-strain, breaking-energy and Young-rate.