Soybean meal (SBM) is the primary source of amino acids in most diets for pigs, but most of the phosphorus (P) in SBM is bound to phytate and is poorly digested by pigs. Microbial phytase is, therefore, widely used to increase P digestibility.

Results of some experiments indicated improvements in energy and amino acid (AA) digestibility with high levels of phytase, but results of other experiments indicated no increase in digestibility of nutrients other than P when microbial phytase was used. Therefore, three experiments were conducted to test the hypothesis that increasing levels of microbial phytase in diets based on SBM will result in increased digestibility of energy, AA and Ca, and that these responses are consistent among different sources of SBM.

Overall, results demonstrate that microbial phytase provides benefits beyond P release and inclusion of microbial phytase in diets for growing-finishing pigs will increase the nutritional value of SBM. Because responses were consistent among the three sources of SBM it is likely that these responses will be obtained regardless of the source of SBM being used.

Feeding high levels of microbial phytase (up to 4,000 FTU/kg) increased ME in SBM by approximately 40 to 50 kcal/kg and improved digestibility of Ca, P and AA. These results support using higher phytase doses to improve nutrient utilization and reduce feed cost in corn–SBM diets for growing pigs.

Read more about these experiments here.