The effect of baicalin on lung microbiota in chicken
To detect whether the protective role of baicalin in APEC-induced colibacillosis was associated with the changes of lung microbiota, we analyzed the lung bacterial community after treated with baicalin alone. The chao-1 and shannon index showed that there was no difference at both bacterial diversity and richness between the CON and BAI group chickens (Fig. 7A-B). In addition, PCoA with unweighted Unifrac distances indicated that CON and BAI groups were no significantly separated at the OUT levels (Fig. 7C). Further research showed that Proteobacteria(CON vs BAI=82.36% vs 78.43%), Firmicutes (CON vs BAI=7.78% vs 12.15%), Bacteroidetes (CON vs BAI=5.45% vs 4.91%), andActinobacteria (CON vs BAI=1.24% vs 1.37%) were the dominant phyla (Fig. 7D and supplementary Table S5), and Stenotrophomonas(CON vs BAI=62.38% vs 56.84%), Delftia (CON vs BAI=3.7% vs 3.9%), Moraxella (CON vs BAI=2.0% vs 4.1%), andSphingomonas (CON vs BAI=4.6% vs 2.9%) genus were the dominant genus in the lung microbiota of chicken, and there are no different were showed in CON and BAI group chickens (Fig, 7E and supplementary Table S6). These results suggested that the protective effect of baicalin on APEC-induced colibacillosis was associated with the changes of gut microbiota rather than the changes of lung microbiota.