6 research outputs found
Age and Diet Affect Gene Expression Profile in Canine Skeletal Muscle
We evaluated gene transcription in canine skeletal muscle (biceps femoris) using microarray analysis to identify effects of age and diet on gene expression. Twelve female beagles were used (six 1-year olds and six 12-year olds) and they were fed one of two experimental diets for 12 months. One diet contained primarily plant-based protein sources (PPB), whereas the second diet contained primarily animal-based protein sources (APB). Affymetrix GeneChip Canine Genome Arrays were used to hybridize extracted RNA. Age had the greatest effect on gene transcription (262 differentially expressed genes), whereas the effect of diet was relatively small (22 differentially expressed genes). Effects of age (regardless of diet) were most notable on genes related to metabolism, cell cycle and cell development, and transcription function. All these genes were predominantly down-regulated in geriatric dogs. Age-affected genes that were differentially expressed on only one of two diets were primarily noted in the PPB diet group (144/165 genes). Again, genes related to cell cycle (22/35) and metabolism (15/19) had predominantly decreased transcription in geriatric dogs, but 6/8 genes related to muscle development had increased expression. Effects of diet on muscle gene expression were mostly noted in geriatric dogs, but no consistent patterns in transcription were observed. The insight these data provide into gene expression profiles of canine skeletal muscle as affected by age, could serve as a foundation for future research pertaining to age-related muscle diseases
Phylogenetic characterization of fecal microbial communities of dogs fed diets with or without supplemental dietary fiber using 454 pyrosequencing.
BACKGROUND: Dogs suffer from many of the same maladies as humans that may be affected by the gut microbiome, but knowledge of the canine microbiome is incomplete. This work aimed to use 16S rDNA tag pyrosequencing to phylogenetically characterize hindgut microbiome in dogs and determine how consumption of dietary fiber affects community structure. PRINCIPAL FINDINGS: Six healthy adult dogs were used in a crossover design. A control diet without supplemental fiber and a beet pulp-supplemented (7.5%) diet were fed. Fecal DNA was extracted and the V3 hypervariable region of the microbial 16S rDNA gene amplified using primers suitable for 454-pyrosequencing. Microbial diversity was assessed on random 2000-sequence subsamples of individual and pooled DNA samples by diet. Our dataset comprised 77,771 reads with an average length of 141 nt. Individual samples contained approximately 129 OTU, with Fusobacteria (23-40% of reads), Firmicutes (14-28% of reads) and Bacteroidetes (31-34% of reads) being co-dominant phyla. Feeding dietary fiber generally decreased Fusobacteria and increased Firmicutes, but these changes were not equally apparent in all dogs. UniFrac analysis revealed that structure of the gut microbiome was affected by diet and Firmicutes appeared to play a strong role in by-diet clustering. CONCLUSIONS: Our data suggest three co-dominant bacterial phyla in the canine hindgut. Furthermore, a relatively small amount of dietary fiber changed the structure of the gut microbiome detectably. Our data are among the first to characterize the healthy canine gut microbiome using pyrosequencing and provide a basis for studies focused on devising dietary interventions for microbiome-associated diseases
Effects of Dietary Fiber on the Feline Gastrointestinal Metagenome
Four healthy adult cats were used in a crossover design
to determine
phylogeny and metabolic functional capacity of the catβs gastrointestinal
microbiota using a metagenomic approach. Healthy adult cats (1.7 years
old) were fed diets containing 4% cellulose, fructooligosaccharides
(FOS), or pectin for 30 d, at which time fresh fecal samples were
collected. Fecal DNA samples from each cat consuming each diet were
subjected to 454 pyrosequencing. Dominant phyla determined using two
independent databases (MG-RAST and IMG/M) included Firmicutes (mean
= 36.3 and 49.8%, respectively), Bacteroidetes (mean = 36.1 and 24.1%,
respectively), and Proteobacteria (mean = 12.4 and 11.1%, respectively).
Primary functional categories as determined by KEGG were associated
with carbohydrates, clustering-based subsystems, protein metabolism,
and amino acids and derivatives. Primary functional categories as
determined by COG were associated with amino acid metabolism and transport,
general function prediction only, and carbohydrate transport and metabolism.
Analysis of carbohydrate-active enzymes revealed modifications in
several glycoside hydrolases, glycosyl transferases, and carbohydrate-binding
molecules with FOS and pectin consumption. While the cat is an obligate
carnivore, its gut microbiome is similar regarding microbial phylogeny
and gene content to omnivores
Phylogenetic and gene-centric metagenomics of the canine intestinal microbiome reveals similarities with humans and mice
This study is the first to use a metagenomics approach to characterize the phylogeny and functional capacity of the canine gastrointestinal microbiome. Six healthy adult dogs were used in a crossover design and fed a low-fiber control diet (K9C) or one containing 7.5% beet pulp (K9BP). Pooled fecal DNA samples from each treatment were subjected to 454 pyrosequencing, generating 503 280 (K9C) and 505 061 (K9BP) sequences. Dominant bacterial phyla included the Bacteroidetes/Chlorobi group and Firmicutes, both of which comprised βΌ35% of all sequences, followed by Proteobacteria (13β15%) and Fusobacteria (7β8%). K9C had a greater percentage of Bacteroidetes, Fusobacteria and Proteobacteria, whereas K9BP had greater proportions of the Bacteroidetes/Chlorobi group and Firmicutes. Archaea were not altered by diet and represented βΌ1% of all sequences. All archaea were members of Crenarchaeota and Euryarchaeota, with methanogens being the most abundant and diverse. Three fungi phylotypes were present in K9C, but none in K9BP. Less than 0.4% of sequences were of viral origin, with >99% of them associated with bacteriophages. Primary functional categories were not significantly affected by diet and were associated with carbohydrates; protein metabolism; DNA metabolism; cofactors, vitamins, prosthetic groups and pigments; amino acids and derivatives; cell wall and capsule; and virulence. Hierarchical clustering of several gastrointestinal metagenomes demonstrated phylogenetic and metabolic similarity between dogs, humans and mice. More research is required to provide deeper coverage of the canine microbiome, evaluate effects of age, genetics or environment on its composition and activity, and identify its role in gastrointestinal disease