Microbial Phytase Use in Swine Diets
Researchers at the University of Illinois determined the effects of graded levels of microbial phytase on the apparent total tract digestibility (ATTD) of phosphorus (P) and calcium (Ca) and the standardized total tract digestibility (STTD) of P in four canola meals and one soybean meal (SBM) fed to growing pigs. Pigs weighing about 16 kg were individually housed in metabolism crates and were randomly allotted to 1 of 20 diets in a 5 × 4 factorial arrangement of treatments with 5 meal sources and 4 levels of phytase (0, 500, 1,500, and 2,500 phytase units/kg). There were 6 replicate pigs per diet. Feces were quantitatively collected for 5-days after a 7-day adaptation period.Results indicated that supplementation of microbial phytase increased (linear, P ‹ 0.05) the ATTD of Ca and increased (linear and quadratic, P ‹ 0.05) the ATTD and STTD of P in this experiment. Regression equations were developed to calculate the response to microbial phytase. The value of this study is that now the response of adding microbial phytase can be predicted by regression equation.