Intestinal ileum bacterial beta diversity at the OTU level. (A) Cobb, (B) Hubbard, and (C) Ross chickens were unsupplemented and uninfected (Control), unsupplemented and E. maxima-infected (EM), unsupplemented and C. perfringens-infected (CP), unsupplemented and E. maxima/C. perfringens co-infected (NE), or oleoresin-supplemented and E. maxima/C. perfringens co-infected (NE + XT). Molecular phylogenetic analysis of 16S rRNA sequences was performed by the maximum likelihood method. The relative lengths of each line in the distance trees are indicated numerically, with longer line indicative of more dissimilar diversity.