Lack of effect of ascorbic and citric acids on calcium metabolism of chickens.

Five experiments were carried out in which various levels of calcium and ascorbic acid or citric acid were fed to adult male chickens, young chickens, or young coturnix. Observations were made on body weight, feed efficiency, plasma calcium and tibia mineral content. One percent dietary ascorbic acid had no adverse effect on body weight, tibia ash or tibia calcium content of adult male chickens over a 224-day period, even at calcium levels as low as 0.026% of the diet. In growing chicks, body weight and plasma calcium and tibia mineral content varied with the calcium level of the diet, but were not influenced by ascorbic acid even at 0.65% of the diet. Citric acid at the same molar level was also ineffective in altering calcium metabolism in growing chickens. Growing coturnix showed differences in growth and tibia ash content with 0.4% and 0.85% calcium, but there were no pronounced effects caused by dietary ascorbic acid. There is no evidence in this work that these relatively high levels of ascorbic acid or citric acid have any adverse effect on calcium metabolism because of their chelating properties.