CALCIUM BIOAVAILABILITY OF CALCIUM CARBONATE BASED DIETS FOR MALE GROWING RATS

Calcium (Ca) bioavailability of different levels of calcium carbonate using male Sprague-Dawley derived weanling rats was determined. Normalized value (NV), the relative bioavailability (RBV) and calcium absorption in three levels (0.14, 0.19 and 0.24 %) of three balanced diets (diets No 1, 2 and 3) of calcium carbonate (CaCO3) as a source of calcium were estimated. Normalized values and RBVs in femur, tibia and fibula for rats fed diet containing 0.19% calcium (No.2) were significantly (P<0.05) higher (81.8 and 100 %, respectively ) than those (78; 95 and 78; 95 ) for rats fed diet containing 0.14% (No.1) (78; 95 and 78; 95, respectively) and diet containing 0.24% calcium (No.3)(60.8; 74.2 and 60.2;73.6, respectively). Results also show that calcium absorption, total body calcium and serum calcium for rats fed diet No.2 were significantly (P<0.05) higher than those of rats fed diets No.1 and 3. It was concluded that calcium carbonate based diet containing 0.19% calcium with 1.5:1 calcium to phosphorus ratio may give high calcium bioavailability for growing rats which was considered as standard (control) diet for other diets.