not affected by feeding level, which is in agreement with
previous observations with growing pigs (De Goey
of this feeding level being below the ME intake
required for maintenance. The increase in urinary energy
excretion as ME intake decreased was also observed in
our study. Pigs will mobilize their body reserves to cover
their energy requirement. Energy can be obtained from
AA oxidation, which results in excretion of the N in the
form of urea (Birkett and de Lange, 2001). Therefore, the
energy in urine originated both from the diet and from
body nutrients. The greater excretion of energy in urine
from pigs at the least feed intake is the reason for the reduced
ME that was calculated for the diet fed to these
pigs. Methane production in the hindgut of growing pigs
represents an energy loss of about 0.2 to 1.0% of DE