Chromic oxide (0.5%) was mixed with all diets to determine apparent digestibility coefficients.
Feces were collected via a siphonage approach every day during last 3 weeks.
Fresh excrements with intact envelops were selected and centrifuged (3,200 rpm at 6C
for 15 min), pooled, dried, and grounded. Proximate (AOAC 1990) and chromic oxide
analyses (Bolin et al. 1952) were conducted for feed and feces.
Analyses of samples were made as follows: crude protein (micro-Kjeldahl method,
nitrogen analyzer, Fison instrument, N = 6.25), crude fat (dichloromethane extraction by
Soxlhet method).