A Comparison of Phosphorus Assay Techniques with Chicks

THE nutritional interrelationships of calcium, phosphorus and magnesium have long been recognized. Chicco et al. (1967) reported that supplementing a degerminated corn-soybean meal type diet with 2,000 p.p.m. of magnesium improved the performance of chicks when the diet was deficient in calcium. However, when the level of calcium was increased to meet the apparent requirement of the chick, this level of magnesium gave a small reduction in body weight and a significant depression of tibia ash. It is an accepted fact that adverse calcium:phosphorus ratios limit the utilization of phosphorus, especially at suboptimal levels such as those used in phosphorus assay diets. In order to eliminate the possibility of calcium being a limiting factor, ideal calcium levels have been determined for use with various levels of phosphorus supplementation from several different phosphate materials (Harms et al., 1967; Damron and Harms, 1968). Magnesium has been shown to significantly influence performance of…