lism (Qian et al. 1996). Supplementing the negative
control diet with MP or MP+OA improved both the mobility
score (P = 0.06) and bone ash content (P = 0.003;
Table 6) to the same levels as those for the control. The
observed improvement in mobility score and bone ash
content for pigs fed the NC+MP and NC+MPOA diets
relative to those fed the negative control diet indicate
that the phosphate groups liberated due to improved
phytate hydrolysis were utilized for bone development.
It is also possible that, by increasing P availability,
MP+OA supplementation reduced the Ca:P ratio, thus
contributing to increased P utilization (Qian et al.,
1996). The present results suggest that addition of MP
alone or MPOA may completely replace the use of inorganic
phosphorus in diets of young pigs. This is in close
agreement with the findings of Han et al. (1998), which
indicated that supplementing a corn–soybean mealbased
diet with microbial phytase (1,200 U/kg) and endogenous
wheat phytase (15% of diet) improved (P =
0.002) mobility of early-weaned pigs relative to diets
without phytase.