Furthermore, the reduction in P excretion when pigs
were fed the NC+MP and NC+MPOA diets was 12.9
and 19.4%, respectively, relative to pigs fed the control
diet. This level of reduction in fecal P excretion is in
close agreement with the values reported by Harper et
al. (1997), who found a 21.5% reduction in P excretion
when diets were supplemented withMP(500 U/kg diet).
However, these values are somewhat lower than the
levels (35 to 42%) reported by Lei et al. (1993a) and
Kornegay and Qian (1996) in studies of younger pigs
fed diets supplemented with higher levels of phytase
than those used in the present study.