Evaluation of Eppawala rock phosphate as a phosphorus supplement in diets for growing chickens and pigs

Abstract

For 12 days, 75 crossbred male chicks, 8 days old, were given a basal diet supplying 0.1% phosphorus from a reference P supplement (potassium dihydrogen orthophosphate), or the basal diet plus 0.05 or 0.1% reference P, or 0.05 or 0.1% Eppawala rock phosphate (ERP). There was virtually no accumulation of tibia ash attributable to P intake from ERP, indicating that the available P content of ERP for growing chickens was virtually nil. In a second experiment, 24 weaned Large White pigs in 3 groups were given up to 20 kg of a control diet, or control diet plus dicalcium phosphate (DCP) 22.1, or ERP 25.5 g/kg diet. From 20 to 50 kg the diets contained DCP 15.5 and ERP 18.0 g/kg. Pigs given the ERP supplemented diet took longer to reach final weight than both other groups, and consumed significantly more feed per unit weight gained than pigs given DCP supplements (3.02 vs. 3.49 kg). Retention of Ca and P in bone was not affected by dietary treatment. It was suggested that the poor performance of ERP was due to its high fluorine content.