Images of DGGE gelwere analyzed using GelCompar II V6.0 software
(AppliedMaths Inc., Texas,USA) and band positions and intensitieswere
also determined. In addition, similarity coefficients and dendograms of
DGGE profiles were calculated using the Dice coefficient and the Unweighted
Pair Group Method using Arithmetic Averages (UPGMA), respectively.
The following diversity indices were calculated as described
by Yu and Morrison (2004): Richness, Evenness and Shannon–Weaver,
with the exception that the Shannon–Weaver index was calculated
using the band surface intensity (area under the Gaussian curve approximating
a band) instead of using the peak height of a band. The resulting
sequences were edited in BioEdit and aligned using ClustalW. All sequences
(≈162 bp)were identified by BLASTn searches in the GenBank
based on the closest known relative in the database for the partial 16S
rRNA. The relative abundance of bacterial species was calculated based
on band surface intensities and band phylogenetic identification. For
all samples, each of the specific band surface intensity was converted
to relative intensity by dividing its intensity on the sum of all band surface
intensities in that lane, and subsequently averaging the relative
band surface intensities for each band across all individual within the
same dietary group.