3.3 Classification of intestinal microbes at different dietary
protein levels
The data presented in Figure 3 show that, at the phylum level, bacteria
present in jejunum and cecum samples from Bamei pigs are mainly
representatives of Firmicutes or Bacteroidetes. The relative abundance
of members of phylum Firmicutes at the three protein levels in jejunum
samples was 92.1%, while the average relative abundance in cecum
samples was 73.88%. Relative abundance values for Bacteroidetes and
Actinobacteria in jejunum samples from test group II were higher than
those recovered from the other two groups. Similarly, relative
abundances of Bacteroidetes in test group II cecum samples were also
higher than those of the other two groups, although this difference is
not significant. Selecting microbes at the phylum level for further
differential analysis shows that members of four of the top ten were
significantly present in jejunum samples. Representatives of phylum
Firmicutes were present in significantly higher numbers in test group II
compared to test group I (P = 0.02), while representatives of
phylum Actinobacteria were present in significantly higher numbers in
test group I compared to the control group (P = 0.011).
Similarly, representatives of phylum Proteobacteria were present in
significantly higher numbers in the control group than in test group II
(P = 0.024), while representatives of phylum Euryarchaeota were
present in significantly higher numbers in test group I than in either
the control group or test group II (P = 0.001). Data for all
other phyla reveal no significant differences while two from cecum
sample did vary. Representatives of phylum Firmicutes were present in
significantly higher numbers in test group II than in test group I
(P = 0.034), while representatives of phylum Bacteroidetes were
present in significantly higher numbers in test group I compared to test
group II (P = 0.011). Data for other phyla show no significant
differences. Comparing microbes at the phyla level in jejunum and cecum
samples shows that representatives of phylum Firmicutes in former
samples occurred at significantly higher levels than in the cecum
(P = 0.032). Representatives of phylum Bacteroidetes in the cecum
were also significantly more abundant than in the jejunum (P = 0.070),
while data for other phyla show no clear differences (P> 0.05).
Bacteria in jejunum and cecum samples at the genus level given different
dietary protein levels mainly include unidentified Clostridiales ,Terrisporobacter , and Turicibacter . Analysis of species
differences shows that just the genus Pseudoscardovia in the
jejunum varied significantly; samples from test group I contain this
genus at significantly higher levels than the control group and test
group II (P = 0.079). Data for other phyla did not vary
significantly. Overall, three significant differences in pig cecum
contents were seen; unidentified Clostridiales composition in
test group II samples was significantly higher than test group I
(P = 0.029) while genus Romboutsia contents in the control
group was significantly higher than in test group I. Composition ofStreptococcus in the control group (P = 0.030) was also
significantly higher than in test group I samples (P = 0.079).
Comparing microbial differences at the genus level between jejunum and
cecum samples, it is clear that representatives of
unidentified_Clostridiales in the former occurred at
significantly higher proportions than in the latter (P = 0.021).
Differences between other phyla were not significant.