2.2. Sample collection and processing
Pigs were fed the experimental diets during three 10-d
periods, and pigs were weighed at the beginning and end
of each period. Feces were collected via grab sampling
from d 6 to 7 of each period. The pH of the fecal samples
was measured immediately after collection, using a pH
meter (PB-10; Sartorius AG, Göttingen, Germany). Ten
grams of each fecal sample was stored at 20 1C until
subsequent analysis for VFA concentration. The remaining
feces were stored in plastic bags at 20 1C. One sample of
ileal digesta was collected continuously from 0830 to
1630 h on d 8 and 10. The digesta collection method was
similar to the excreta collection procedure described by
Chen et al. (2013). From each bag of ileal digesta, 5 g of
subsample was collected. These samples were combined
by pig and collection period, and stored at 20 1C until
subsequent VFA analysis. The pH of ileal samples collected
from each pig was measured as described for the fecal
samples. At the conclusion of each collection period,
samples were thawed and mixed by individual animal,
and a subsample was collected for chemical analysis. Ileal
and fecal samples were lyophilized and ground before
analysis.