The changes of gut microbiota induced by treating with APEC
and/or baicalin in chicken
The composition of gut microbiota in control (CON), baicalin-treated
(BAI), APEC-treated (APEC), baicalin+APEC treatment (BAI+APEC) group
chickens were differed in high-confidence OTUs, with lower diversity and
richness in BAI group compared to CON group (Fig. 4A). In addition,
infection of APEC significantly increased the microbiota diversity and
richness compared to the CON group chickens (Fig. 4B-C). However,
pre-treatment with BAI before APEC infection (BAI+APEC) reduced the
higher levels of microbiota diversity and richness induced by APEC (Fig.
4B-C).
Furthermore, the changes of bacterial phyla in different treatment group
chickens were showed that though gut microbiota in different treatment
groups chicken were dominated by Firmicutes(means=87.32%-96.70%), Proteobacteria (means=0.62%-11.6%),Tenericutes (means=1.0%-2.16%), and Actinobacteria(means=0.20%-0.79%) (Fig. 5A and Table S3). Infection of APEC reduced
the relative abundance of Proteobacteria , and increased the
relative abundance of Actinobacteria compared to the CON group
chickens, while BAI treatment (BAI+APEC) group reversed those changes
induced by APEC (Fig. 5B). In addition, the relative abundance ofProteobacteria in BAI group was higher than those in CON group
chickens, while Actinobacteria was lower than those in CON group
chickens (Fig. 5B).
Moreover, the characteristics of microbiota composition at the genus
level were detected at the top 20 most abundant taxa indicated that the
gut bacterial was dominated by Lachnospiraceae_unclassified ,Ruminococcaceae_UCG-014 , Ruminococcaceae_unclassified ,Intestinimonas , Blautia , Escherichia-Shigella ,Erysipelatoclostridium , Ruminococcus_torques_group ,Clostridiales_vadin BB60-group_unclassified , andFournierella (Fig. 5C and supplementary Table S4). Furthermore,
t-test analysis revealed infection of APEC increased the abundance ofRuminococcaceae_UCG-014 , Ruminococcaceae_unclassified ,Clostridiales_vadinBB60_group_unclassified , andRuminiclostridium_5 , while reduced the abundance ofLachnospiraceae_unclssified , Blautia ,Escherichia-Shigella , and Pygmaiobacter . However, those
changes were reversed in BAI+APEC group (Fig. 5D).
In addition, the proportion of shared bacterial genera among CON, BAI,
APEC, and BAI+APEC group chickens were 25.72%, 23,63%, 19.03%, and
22.01% (Fig. S3). Furthermore, to evaluated whether a unique bacterial
was associated with the protective role of BAI during APEC-induced
chicken colibacillosis, we conducted a biomarker analysis by linear
discriminant analysis (LDA = 4.0) effect size (LEfSe) and a cladogram
generated from LEfSe analysis on the microbiota on the different
treatment group chickens. At both genus and species levels,Clostridiales_vadinBB60_group_unclassified ,Ruminococcaceae_UCG_014 , andRuminococcaceae_unclassified were enriched in the chicken of
infected with APEC compared to the CON group chickens (Fig. 6A-B). While
pretreatment of BAI partly inhibited these bacteria induced by APEC
(Fig. 6C-D). In addition, compared to the CON group chickens,Intestinimonas genera was enriched in the chicken of treated with
BAI (Fig. 6E-F). These results suggested that baicalin may protect
against chicken colibacillosis partly by reversing the changes of gut
microbiota induced by APEC.