Soybean meal (SBM) is commonly used as a source of amino acids in swine diets because of its high protein content (Kudelka et al., 2021).  In addition, SBM contributes with energy and phosphorus (P). However, high portion of the P in SBM is bound to phytate, which is indigestible by pigs. Therefore, microbial phytase enzyme is supplemented in swine diets. The impact of phytase on the digestibility of P is well documented, however some experiments on digestibility in corn–SBM diets has been reported energy increase if microbial phytase was used (Liao et al., 2005; Arredondo et al., 2019; Lala et al., 2020; Espinosa et al., 2022), but, not in others (She et al., 2018; Mesina et al., 2019; Lamp and Moritz, 2022). There is, however, a lack of information about the impact of microbial phytase on the digestibility of energy in SBM. It is also not known if a possible effect of microbial phytase on energy digestibility in SBM is consistent among different sources of SBM.

Pigs have a poor utilization of phytate-bound P derived from plant feed ingredients and thus supplemental phytase is used in pig diets (Selle and Ravindran, 2008). Use of phytase in diets has been a very effective way to increase P digestibility, but the digestibility of amino acids, energy, and other minerals may also be increased by super dosing phytase (Kies et al., 2006; Arredondo et al., 2019), which ultimately increases growth performance and bone ash of pigs.

Bestzyme has recently been developed as a novel phytase, but there is limited information on how this phytase works on growth performance and bone ash of pigs. Therefore, the objective of this experiment was to test the hypothesis that dietary P and Ca in diets for growing pigs can be reduced without negatively impacting growth performance and bone ash of pigs if Bestzyme phytase is included in the diets.