Heterogeneous size datasets of broiler intestinal microbial communities can be analyzed without normalization.

Next-generation sequencing technologies have become a powerful tool for the analysis of microbial communities. Sequencing of the hypervariable regions of the 16S ribosomal RNA gene following the amplitag amplification process has allowed the study of the diversity of samples of diverse origin. According to previous reports, the number of sequences required for the correct determination of the composition of a given sample may vary with the degree of diversity of that sample. In this paper, we investigate the correctness of comparing heterogeneous size datasets of bird intestinal microbial communities obtained from pyrosequencing data (Roche 454 technology) without prior normalization. We conclude that the differences observed between samples are due mainly to individual differences, not to differences in the number of readings in each sample, which makes data normalization unnecessary with the conditions described here.

Effects of feed additives on ileal mucosa-associated microbiota composition of broiler chickens.

The effects of dietary supplementation with 2 recently developed feed additives on the composition of the mucosa-associated microbiota of the ileum were studied in growing broiler chickens. A total of 48 male 1-d-old broiler chickens of the Cobb 500 strain were distributed in 4 treatments with 2 replicates of 6 birds each. The 2 additives tested were a di-d-fructose dianhydride­enriched caramel (FC) and the garlic derivative propyl propane thiosulfonate (PTS-O). Dietary treatments were a control (commercial diet with no additive), INU (20 g inulin/kg diet), CAR (20 g FC/kg diet), and GAR (90 mgPTS-O/kg diet). As a result of this study, inulin supplementation resulted in lower (P < 0.05) and FC feeding resulted in higher (P < 0.05) Blautia coccoides/Eubacterium rectale log10 number of copies respect to controls. Higher (P < 0.05) bifidobacteria log10 number of copies with respect to the controls was determined in the ileal mucosa of birds fed the PTS-O­supplemented diet. Denaturing gradient gel electrophoresis and PCR analysis on Bifidobacterium spp. revealed the presence of Bifidobacterium longum, Bifidobacterium pseudolongum, and Bifidobacterium pseudocatenulatum in samples from chickens fed the control and the PTS-O­supplemented diet. Bifidobacterium longum was exclusively found in poultry fed the control diet, whereas B. pseudocatenulatum was found only in poultry fed the PTS-O­supplemented diet. This study showed that both PTS-O and FC were able to modulate the composition of the ileal mucosa-associated microbiota of growing broiler chickens. Finally, in addition to B. pseudolongum, the presence of B. longum and B. pseudocatenulatum, species not previously described in intestinal samples of broilers, was also demonstrated.