Evaluation of Calcium Bioavailability of some Common Commercial Calcium Carbonates and its Effect on Bone Function and Physical and Chemical Properties in Broilers

Calcium in the diet of broiler chickens is effective on growth, feed efficiency, bone growth, leg health, nervous system function and body immunity. It is essential to provide calcium in sufficient amount to achieve optimal performance in broiler chickens. In order to accurately meet the calcium needs of poultry, one should be aware of the amount of bioavailable calcium in food and calcium sources. Therefore, an experiment was conducted to evaluate the calcium bioavailability of some commercial calcium carbonates and its effect on the function and physical and chemical characteristics of bone in broiler chickens..

Four samples of commercial calcium carbonate, which have the highest production in Iran, were prepared. Then, according to standard methods, the amounts of heavy elements and their solubility in acid were determined. According to the measured characteristics, two carbonates which had better quality were selected and the bioavailability of calcium was determined using 180 male chickens by the standard curve method. Each diet was provided to chickens with 6 replications and 5 birds in each replication for two weeks from 7 to 21 days.

The results of the present study showed that among the carbonates tested, the highest solubility was carbonate Atlas, then carbonate Alborz, and the rest of the carbonates had lower solubility (p<0.01). The highest amount of calcium was related to carbonate Atlas (37.8) and then carbonate B (37.13).  The other calcium soureses had less calcium levels. Carbonate Atlas and Alborz had less poisonus elements. Calcipiure was applied as standard calcium source. The estimated bioavailability based on body weight was 99% for carbonate Atlas and 98.6% in carbonate Alborz. The estimated bioavailability based on the FCR for carbonate A was 121.7% and carbonate B was 92.8%. Estimated bioavailability based on tibial ash was 111.9% for carbonate Atlas and 106% in carbonate Alborz. The estimated bioavailability based on the percentage of tibia calcium was 101.4% for carbonate A and 89.5% in carbonate Alborz. The estimated bioavailability based on tibia calcium strength was 108% for carbonate Atlas and 101% in carbonate Alborz.

In general, the results of the present study showed that the selected carbonates have an acceptable quality as a source of calcium in poultry diets.