Effect of crude protein and phosphorus level in a phytase supplemented grower finisher pig diet on phosphorus and calcium metabolism

Abstract

The objective of this study was to investigate the effects of dietary crude protein level (CP) on mineral metabolism in a low and high phosphorus (P) diet supplemented with phytase. A 2 × 2 factorial experiment was conducted to investigate the effect of CP inclusion (130 versus 200 g/kg) and dietary P inclusion (4.0 versus 6.0 g/kg) on P and calcium (Ca) metabolism in pigs. The dietary treatments contained 500 FTU/kg of phytase. Sixteen entire male pigs (body weight 78 kg) were randomly allocated to the diets in a digestibility and mineral balance study. Pigs offered high P diets had higher faecal dry matter output (P < 0.05) than pigs offered low P diets. Pigs offered low P diets had a higher dry matter digestibility (P < 0.01) than those offered high P diets. Pigs offered high CP diets had a higher urine pH than those offered low CP diets (P < 0.001). Pigs offered low P diets had higher N digestibility than those offered high P diets (P < 0.05). Pigs offered low P diets had a higher P (P < 0.05) and Ca (P < 0.01) digestibility than those offered high P diets. In conclusion dietary CP level had little impact on Ca and P digestibility however offering grower finisher pigs a high P diet supplemented with phytase resulted in a decrease in N digestibility.