Supplemental phytase increases phosphorus digestibility in pigs regardless of phytase source or feed pelleting

Abstract

Two experiments were conducted to investigate the effects of phytase source and feed pelleting on digestibility of dry matter (DM), crude protein, organic matter (OM), and phosphorus (P) with different doses of supplemental phytase in pigs. In Exp. 1, ten barrows (31.4 ± 3.5 kg of body weight) were individually housed in metabolism crates and were allotted to a replicated 5 × 6 Latin square design with 5 diets and 6 periods. In Exp. 2, ten barrows (28.2 ± 3.2 kg of body weight) were individually housed in metabolism crates and were allotted to a replicated 5 × 5 Latin square design with 5 diets and 5 periods. Each period lasted for 10 days consisted of a 5-day adaptation period and a 5-day collection period, and the marker-to-marker method was used for fecal collection. In both experiments, a basal diet was prepared based on corn and soybean meal without phytase or inorganic P. Four experimental diets were prepared in a 2 × 2 factorial treatment arrangement with 2 phytase sources (Buttiauxella spp. or Escherichia coli) and 2 feed forms (mash or pellet). Supplemental dietary phytase concentrations were 500 and 1500 phytase units (FTU)/kg in Exp. 1 and 2, respectively. In Exp. 1, supplemental phytase at 500 FTU/kg increased apparent total tract digestibility of P (P < 0.001) with no effects of phytase source or feed pelleting. Feed pelleting increased digestibility of DM, crude protein, and OM (P < 0.001). In Exp. 2, supplemental phytase at 1500 FTU/kg increased apparent total tract digestibility of P (P < 0.001) with no effects of phytase source or feed pelleting. Feed pelleting increased digestibility of DM and OM (P < 0.001). Based on the results from the 2 experiments, supplemental phytase at 500 and 1500 FTU/kg increased P digestibility in pigs regardless of phytase source or feed pelleting, and feed pelleting increased nutrient digestibility.