In
the present study, the ATTD of Ca in the corn–SBM
diets supplemented with OMM or IMM were between
62 and 70%, which are in good agreement with values
reported by Stein et al. (2008) and Almeida and Stein
(2010), but the ATTD of Ca in the corn–SBM diet without
micromineral supplementation was only 56.8%. The
low levels of Cu and Zn in these diets may have impaired
the efficiency of Ca absorption in the corn–SBM
diet (Dove, 1995). Compared with corn–SBM diets, the
increased Ca retention and ATTD in pigs fed corn grits
diets also indicates that feeding low-phytic acid diets
may increase the efficiency of Ca absorption, which
agree with data from Spencer et al. (2000), Veum et al.
(2001), and Bohlke et al. (2005).