An investigation of calcium citrate-malate as a calcium source for young broiler chicks.

Two experiments were conducted to compare a sample of calcium citrate-malate (CC-M) with a sample of commercial-grade limestone in starting broiler chick diets. In the first experiment, with 0.7 or 0.9% calcium from limestone or CC-M, no differences in bone development (dry fat-free tibia, tibia weight, tibia ash, or tibia calcium) were observed due to calcium source. However, chicks fed the diets based on CC-M had better 0- to 18-d body weight gains and feed conversion ratios than those fed limestone. In the second experiment with 0.50, 0.55, 0.60, 0.65, or 0.70% calcium from limestone or CC-M, chicks again had better body weight gains when fed CC-M compared to those fed limestone. Chicks fed diets based on CC-M and NaP2PO4 had very similar bone development and tibial dyschondroplasia pathology to those fed limestone and Na2H2PO4. However, a control group of chicks fed 0.70% calcium from limestone and dicalcium phosphate did not grow as well as the others and had lower weights of tibia and tibial bone ash, calcium, and phosphorus compared to the others. It is concluded that CC-M is a good calcium source, comparable in bioavailability to limestone. Although CC-M may improve broiler growth, its action is not through increased bioavailability of calcium.