Various sources of supplemental phosphorus for grower/finisher pig diets based on plant protein

Abstract

Three phosphate sources were evaluated for grower finisher pigs in a factorial experiment involving two levels of feeding (restricted and ad libitum), and six diets based on barley and soybean meal. Three diets were supplemented with either 1.0% dicalcium phosphate, 1.2% rock phosphate or 1.3% bone char. Two diets contained combinations of these three phosphate sources, and the sixth diet was unsupplemented and contained only 0.36% total phosphorus. The performance of five pigs, three males and two females, on each treatment was observed between 24 and 75 kg liveweight. There was no significant difference in feed-conversion efficiency or carcase quality of pigs given the six diets. However, the ash content of the fibula bone from pigs receiving the diet without supplemental phosphorus was significantly less than that of pigs receiving supplemental phosphorus. Pigs receiving no phosphate supplement also tended to eat less than pigs given a phosphate supplement when feeding was ad libitum. The apparent digestibility of phosphorus in the unsupplemented diet (29.6%) was similar to that in diets containing either 1.0% dicalcium phosphate or 1.2% rock phosphate, but was significantly less than that in the diet containing 1.3% bone char (47.8%).