Cecal Microbiota Contribute to the Development of Woody Breast Myopathy

ABSTRACT The objective of this study was to characterize the bacterial diversity of cecal microbiota in broilers related to breast phenotype, diet, and genetic strain. Broilers from two genetic strains (120 birds/strain) were fed a control diet (15 birds/pen) and an amino acid reduced diet (15 birds/pen, digestible lysine, total sulfur amino acids, and threonine reduced by 20% compared to the control diet). At 8 weeks of age, 4 male broilers with normal breast (NB, 1 chick per pen) and 4 male broilers with woody breast (WB, 1 chick per pen) were selected for each treatment (strain × diet). The DNA of cecal samples were extracted and the 16S rRNA genes were sequenced and analyzed. There were no differences (P > 0.05) in the alpha diversity of gut microbiota between two phenotypes (NB vs. WB), two strains, or two diets (control vs. reduced). However, principal coordinate analysis plots (beta diversity) revealed that there were composition differences in samples between the two phenotypes (P = 0.001) and the two diets (P = 0.024). The most abundant phyla in all samples were Firmicutes, followed by Bacteroidetes and Proteobacteria. There were differences (false discovery rate, FDR 0.05) between the two genetic strains. Selenomonas bovis (12.6%) and Bacteroides plebeius (12.3%) were the top two predominant bacteria in the ceca of WB birds; however, the relative abundances of these two bacteria were only 5.1% and 1.2% in NB birds, respectively. Function analysis predicted that the metabolic activities differed (q