بررسی کلسیم سیترات-مالات به عنوان منبع کلسیم برای جوجه های جوان گوشتی An Investigation of Calcium Citrate-Malate as a Calcium Source for Young BroilerChicks

ABSTRACT 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 (Key words: calcium citrate-malate, broiler, limestone) 2002 Poultry Science 81:1149–۱۱۵۵ INTRODUCTION Recent reports have shown that calcium citrate-malate (CC-M), a compound used to fortify food with calcium for human consumption, is 10 times more soluble than calcium citrate, which is more soluble than calcium carbonate (Andon et al., 1996; Heaney et al., 1990; Smith et al., 1987). Results from studies with humans also demonstrate that calcium absorption and retention from CCM-fortified food is significantly greater than food forti- fied with calcium carbonate (Andon et al., 1996; Miller et al., 1988). In animal studies, trabecular bone was significantly affected by calcium source and level (Kochanowski, 1990). Rats fed CC-M had 23 to 25% more trabecular bone than those rats fed calcium carbonate at 4 wk, and by 12 wk the difference increased to 44%. Based on these results, it is concluded that calcium in CC-M is more bioavailable than calcium from calcium carbonate. Because of these differences in mammalian species, it is ۲۰۰۲ Poultry Science Association Inc. Received for publication September 14, 2001. Accepted for publication February 6, 2002. 1 Supported by state and Hatch funds allocated to the Georgia Agricultural Experiment Stations of The University of Georgia and the U.S. Poultry and Egg Association. 2 Present address: U.S. Food and Drug Administration, Center for Veterinary Medicine, HFV-222, 7500 Standish Place, Rockville, MD 20855. 3 To whom correspondence should be addressed: gpesti@arches. uga.edu. 1149 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. of interest to evaluate CC-M as a source of calcium in poultry diets, especially in early chick development. In growing chicks, tibial dyschondroplasia (TD) is a major skeletal problem and is associated with calcium and phosphorus deficiency and imbalance. The TD lesion is characterized by a mass of white, opaque, unmineralized, unvascularized cartilage and is found predominantly in the proximal metaphysis of the tibiotarsus. The lesion is a result of the failure of the prehypertropic cartilage cells to undergo normal maturation and vascularization (Riddell, 1975; Poulos et al., 1978; McCaskey et al., 1982). Birds afflicted with severe cases of TD generally have bowed legs. They sit on their hocks and are reluctant to move. Birds with TD spend a significant portion of their time on their breasts, resulting in a higher incidence of breast blisters. In most instances, only a very small percentage of the birds affected by TD show clinical symptoms. Both clinical and subclinical cases can result in economic loss due to trimming and down-grading of carcasses (Burton et al., 1981).