A Comparison of Phosphorus Assay Techniques with Chicks: 7. Comparison of the Relative Performance of Eight Phosphate Sources

Abstract

SEVERAL studies have been conducted in an effort to establish the comparative utilization by chicks of phosphorus from various supplements. These reports were reviewed by Motzok et al. (1956) and Hurwitz (1964). In these studies the bilogical availability was derived by relating the percentage of tibia, beak, or toe ash of chicks fed a test phosphate to that of chicks fed a reference phosphate.In the past, considerable variation in the assay procedure employed has existed. One important variation has been in the calcium: phosphorus ratios or total calcium levels used in the experimental diets. Waldroup et al. (1965) reviewed certain experiments in which this was the case. In this paper it was pointed out that variations in the calcium content of the diet used in assaying phosphorus sources may significantly influence the relative biological value of a particular phosphate source. It was suggested that the use of a different…