The Availability of Phosphorus from Different Sources for Poults Fed Practical-type Diets

APREVIOUS study (Wilcox et al., 1954) determined the effects of various phosphates in a purified diet on the body weight, bone ash percentage and mortality to four weeks of age of Beltsville Small White poults. In this study, three samples of “colloidal” phosphate (also known as “soft phosphate in colloidal clay,” “phosphatic clay” or “soft phosphate”) and two samples of imported rock phosphates were found to be unsatisfactory in availability. Tribasic calcium phosphate, N.F. IX, and beta tricalcium phosphate were found to be intermediate in availability. The results with the poults receiving diets supplemented with “colloidal” phosphate were similar to the results of chick studies by Gillis et al. (1954), Miller and Joukovsky (1953), and Grau and Zweigart (1953). These investigators concluded that “colloidal” phosphates were not satisfactory as phosphorus supplements. Miller and Joukovsky (1953) found an imported rock phosphate to be a source of readily available phosphorus for New …