A Comparison of Phosphorus Assay Techniques with Chicks

EXTENSIVE evaluation has been conducted by many researchers to determine relative availability of both organic and inorganic phosphorus sources using several biological and chemical criteria. Plant phosphorus has been reported to be low in biological availability for the chick and the rat by Lowe et al. (1939), Krieger et al. (1940 (1941), Spitzer et al. (1948), Gillis et al. (1949 (1957), and Matterson et al. (1946). However, Waldroup et al. (1965) reported that optimum weight gains but not maximum mineralization could be obtained from a hominy feed diet which contained 0.5 percent phosphorus, all of which came from an organic source. These weight gains were superior to those obtained from a degerminated corn meal diet which had a total of 0.5 percent phosphorus with 0.2 percent from inorganic sources. The phosphorus supplemented degerminated corn diet in Waldroup’s trial was far superior to the all-plant phosphorus 0.5 percent levels for bone…