Soybean meal (SBM) is one of the most important protein sources in swine diets. However, most P in SBM is bound to phytate, which increases inclusion of inorganic P in diets for pigs. Use of microbial phytase may hydrolyze phytate and subsequently improve P absorption. Fermex 200 (Purina Animal Nutrition, Shoreview, MN, USA) is a new source of fermented SBM that may serve as an alternative to other protein sources in diets fed to pigs. However, there are at this point no data for effects of adding phytase to diets containing Fermex 200 and no data for digestible energy (DE) and metabolizable energy (ME) concentrations of Fermex 200.
Therefore, 2 experiments were conducted to test the hypothesis that inclusion of 1,000 phytase units (FTU)/kg of microbial phytase improves the standardized total tract digestibility (STTD) of P in conventional SBM and Fermex 200. The second hypothesis was that the STTD of P, as well as concentrations of DE and ME in Fermex 200 are greater than in conventional SBM.