Effect of source of supplemental protein and calcium on the phosphorus requirements of broiler chicks in cages

Abstract

In two experiments the phosphorus requirement of broiler chicks in cages was studied using soybean meal and peanut meal as alternative protein supplements, and ground dolomitic limestone and precipitated calcium carbonate as alternative calcium supplements. The broiler chicks used in these experiments survived well on diets containing only 0.33-0.37 per cent plant phosphorus. The addition of 0.1 5 per cent inorganic phosphorus to such diets significantly improved liveweight gain and efficiency of feed conversion. Tibia ash content increased with each addition of inorganic phosphorus. The plant-protein supplements had no differential effects on the phosphorus requirement of the broiler chicks. Ground dolomitic limestone as compared with precipitated calcium carbonate depressed liveweight gain and tibia ash content. The optimum levels of calcium and phosphorus for maximum growth and tibia ash content were 0.6 and 0.57 per cent of the diet, respectively. Under the conditions of these experiments, the requirement of total phosphorus for broiler chicks during the first four weeks of life was between 0.57 and 0.62 per cent of the diet. Of this total phosphorus requirement, about 0.15 to 0.20 per cent should be in the inorganic form.