Composition, spatial distribution, and diversity of the bacterial communities in the rumen of cows fed different forages.
ABSTRACT The species composition, distribution, and biodiversity of the bacterial communities in the rumen of cows fed alfalfa or triticale were investigated using 16S rRNA gene clone library analyses. The rumen bacterial community was fractionated and analyzed as three separate fractions: populations in the planktonic, loosely attached to rumen digesta particles, and tightly attached to rumen digesta particles. Six hundred and thirteen operational taxonomic units (OTUs) belonging to 32 genera, 19 families, and nine phyla of the domain Bacteria were identified from 1014 sequenced clones. Four hundred and fifty one of the 613 OTUs were identified as new species. These bacterial sequences were distributed differently among the three fractions in the rumen digesta of cows fed alfalfa or triticale. Chao 1 estimation revealed that, in both communities, the populations tightly attached to particulates were more diverse than the planktonic and those loosely attached to particulates. S-Libshuff detected significant differences in the composition between any two fractions in the rumen of cows with the same diet and between the communities fed alfalfa and triticale diets. The species richness estimated for the communities fed alfalfa and triticale is 1027 and 662, respectively. The diversity of the rumen bacterial community examined in this study is greater than previous studies have demonstrated and the differences in the community composition between two high-fiber diets have implications for sample selection for downstream metagenomics applications.
- SourceAvailable from: Tatiana A Vishnivetskaya[Show abstract] [Hide abstract]
ABSTRACT: Many microbial phyla that are widely distributed in open environments have few or no representatives within animal-associated microbiota. Among them, the Chloroflexi comprises taxonomically and physiologically diverse lineages adapted to a wide range of aquatic and terrestrial habitats. A distinct group of uncultured chloroflexi related to free-living anaerobic Anaerolineae inhabits the mammalian gastrointestinal tract and includes low-abundance human oral bacteria that appear to proliferate in periodontitis. Using a single-cell genomics approach, we obtained the first draft genomic reconstruction for these organisms and compared their inferred metabolic potential with free-living chloroflexi. Genomic data suggest that oral chloroflexi are anaerobic heterotrophs, encoding abundant carbohydrate transport and metabolism functionalities, similar to those seen in environmental Anaerolineae isolates. The presence of genes for a unique phosphotransferase system and N-acetylglucosamine metabolism suggests an important ecological niche for oral chloroflexi in scavenging material from lysed bacterial cells and the human tissue. The inferred ability to produce sialic acid for cell membrane decoration may enable them to evade the host defence system and colonize the subgingival space. As with other low abundance but persistent members of the microbiota, discerning community and host factors that influence the proliferation of oral chloroflexi may help understand the emergence of oral pathogens and the microbiota dynamics in health and disease states.Environmental Microbiology 05/2014; · 5.76 Impact Factor
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ABSTRACT: Host and dietary interactions with the rumen microbiome can affect the efficacy of supplements, and their effect on the composition of the bacterial population is still unknown. A 16S rRNA metagenomic approach and Next-Generation Sequencing (NGS) technology were used to investigate the bacterial microbiome composition in the liquid fraction of the rumen content collected via stomach tubing. To investigate biodiversity, samples were taken from three groups of four lactating dairy cows given a supplement of either 50 g of potato protein (Ctrl group), or 50 g of lyophilized Saccharomyces cerevisiae (LY group) or 50 g of dried S. cerevisiae (DY group) in a potato protein support. Rumen samples were collected after 15 days of dietary treatments and milk production was similar between the three groups. Taxonomic distribution analysis revealed a prevalence of the Firmicutes phylum in all cows (79.76%) and a significantly (P<0.05) higher presence of the genus Bacillus in the DY group. Volatile fatty-acid concentration was not significantly different between groups, possibly because of relatively high inter-animal variability or limited effect of the treatments or both, and the correlation analysis with bacterial taxa showed significant associations, in particular between many Firmicutes genera and butyrate. Limited differences were observed between dietary treatments, but the lack of microbiome data before yeast administration does not allow to draw firm conclusions on the effect of dietary treatments.animal 02/2014; · 1.65 Impact Factor
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ABSTRACT: Intestinal bacteria play an important role in animal health. They extract and process nutrients present in their host's diet, help to develop their host's immune system, and recycle organic compounds, water, and minerals. The gut bacterial diversity is poorly known in wild animals. This study is the first description of the diversity of bacteria along the whole intestine of a wild bird (Passer domesticus). Pyrose-quencing of the 16S rRNA gene unveiled a high bacterial diversity, distributed in 11 bacterial phyla. The most abundant groups were Pro-teobacteria and Firmicutes. Bacterial diversity was greater in the upper section of the intestine and decreased toward the final portion of the gut. After a conservative denoising of the sequences, we found 4,436 OTUs in the gut of P. domesticus. Our data shows that the diversity of intestinal bacteria in the gut of wild birds is much larger than what had previously been estimated using fecal samples. 1 Introduction The gastrointestinal tract of animals is a complex ecosystem influenced both by the intrinsic characteristics of the ani-mal's gut, and the ensemble of bacteria, Archaea, protozoa, and fungi that dwell in it [30, 63]. All these microorganisms are present in immense numbers and are collectively known as the gut microbiota [5, 74]. The microbiota is involved in many functions like synthesis of vitamins [41, 52, 59], enzy-matic digestion [30, 33, 57], nutrient, salt and water recy-cling [46, 63], and activation of the host's immune system [2, 26, 68]. Despite the importance of bacteria in the gut micro-biota, little is known about its diversity and functional role inside intestinal ecosystems of wild animals [44, 45, 59]. The study of intestinal bacteria has been limited by our capacity to cultivate them under laboratory conditions .Metagenomics 07/2014; 3(11).