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The characterization of the microbial population of many niches of the organism, as the gastrointestinal tract, is now possible thanks to the use of high-throughput DNA sequencing technique. Several studies in the companion animals field already investigated faecal microbiome in healthy or affected subjects, although the methodologies used in the different laboratories and the limited number of animals recruited in each experiment does not allow a straight comparison among published results. In the present study, we report data collected from several in house researches carried out in healthy dogs, with the aim to seek for a variability of microbial taxa in the faeces, caused by factors such as diet and sex. The database contains 340 samples from 132 dogs, collected serially during dietary intervention studies. The procedure of samples collection, storage, DNA extraction and sequencing, bioinformatic and statistical analysis followed a standardized pipeline. Microbial profiles of faecal samples have been analyzed applying dimensional reduction discriminant analysis followed by random forest analysis to the relative abundances of genera in the feces as variables. The results supported the responsiveness of microbiota at a genera taxonomic level to dietary factor and allowed to cluster dogs according this factor with high accuracy. Also sex factor clustered dogs, with castrated males and spayed females forming a separated group in comparison to intact dogs, strengthening the hypothesis of a bidirectional interaction between microbiota and endocrine status of the host. The findings of the present analysis are promising for a better comprehension of the mechanisms that regulate the connection of the microorganisms living the gastrointestinal tract with the diet and the host. This preliminary study deserves further investigation for the identification of the factors affecting faecal microbiome in dogs., Competing Interests: DL and SDM are employees of ARGO Open Lab Platform for Genome sequencing, AREA Science Park, Padriciano, Trieste, Italy. Remuneration was not received for drafting, reviewing, or approving the manuscript for publication. None of these declarations alter our adherence to PLOS ONE policies on sharing data and materials. There are no patents, products in development or marketed products associated with this research to declare.

Background: Dietary intervention studies are required to deeper understand the variability of gut microbial ecosystem in healthy dogs under different feeding conditions and to improve diet formulations. The aim of the study was to investigate in dogs the influence of a raw based diet supplemented with vegetable foods on faecal microbiome in comparison with extruded food., Methods: Eight healthy adult Boxer dogs were recruited and randomly divided in two experimental blocks of 4 individuals. Dogs were regularly fed a commercial extruded diet (RD) and starting from the beginning of the trial, one group received the raw based diet (MD) and the other group continued to be fed with the RD diet (CD) for a fortnight. After 14 days, the two groups were inverted, the CD group shifted to the MD and the MD shifted to the CD, for the next 14 days. Faeces were collected at the beginning of the study (T0), after 14 days (T14) before the change of diet and at the end of experimental period (T28) for DNA extraction and analysis of metagenome by sequencing 16SrRNA V3 and V4 regions, short chain fatty acids (SCFA), lactate and faecal score., Results: A decreased proportion of Lactobacillus, Paralactobacillus (P < 0.01) and Prevotella (P < 0.05) genera was observed in the MD group while Shannon biodiversity Index significantly increased (3.31 ± 0.15) in comparison to the RD group (2.92 ± 0.31; P < 0.05). The MD diet significantly (P < 0.05) decreased the Faecal Score and increased the lactic acid concentration in the feces in comparison to the RD treatment (P < 0.01). Faecal acetate was negatively correlated with Escherichia/Shigella and Megamonas (P < 0.01), whilst butyrate was positively correlated with Blautia and Peptococcus (P < 0.05). Positive correlations were found between lactate and Megamonas (P < 0.05), Escherichia/Shigella (P < 0.01) and Lactococcus (P < 0.01)., Conclusion: These results suggest that the diet composition modifies faecal microbial composition and end products of fermentation. The administration of MD diet promoted a more balanced growth of bacterial communities and a positive change in the readouts of healthy gut functions in comparison to RD diet.

A growing number of studies in the last decade described the microbial populations in different niches of the organism thank to High-throughput DNA sequencing techniques, that are easily accessible to researchers. Furthermore, network analysis allows characterisation of bacteria that are indirectly linked to outcomes such as disease, diet and host sex through their association with other taxa. The present work on the gut microbiome follows previous research in which data were collected from 8 in-house dietary intervention studies in healthy dogs. Animals were divided according to diet and sex. The process of sample collection, storage, DNA extraction and sequencing, bioinformatic and statistical analysis followed a tailored, internally defined pipeline. The extracted DNA was prepared for sequencing of the V3 and V4 regions of the 16 rRNA gene. Correlation network analysis was performed by calculating pairwise relationships between taxa using the Sparse Correlations for Compositional Data (SparCC) algorithm. First, we identified candidate bacteria that were highly abundant in the microbial community, and second, we examined taxa that were directly related to diet and sex factors. In summary, this study underpins the network structure of the gut microbiome of dogs categorised by diet and sex and provides a better explanation for the interactions between bacteria that led to the grouping of dogs based on environmental or genetic factors. Specifically, this study has provided the basis for understanding how the bacterial community in the gut is interconnected and functions as a function of diet composition and sex. Network analysis could allow indirect association between bacteria composing the gut microbiome and outcomes, such as disease, diet and sex of the host. This research put the basis on the definition of enterotypes also in dogs, a concept already applied in humans. Positively correlated bacteria, belonging to modules could help to modulate diets and therapies for the treatment of enteropathies or gut-related pathologies linked to a dysbiosis status of the host. [ABSTRACT FROM AUTHOR]

The aim of the study was to investigate element concentrations in the hair of growing and adult dogs. Overall, 39 dogs were recruited in a kennel, split in 4 groups: G1, 10 puppies of small size breeds; G2, 6 puppies of medium size breed; G3, 11 adult dogs of medium size breeds; G4, 12 adult dogs of toy breeds. The dogs of each group were fed 4 different complete diets, according to the requirements. Hairs were sampled at the beginning of the study (D0) and after 60 days (D60). Elements were analysed in triplicate using ICP-OES. In the hair of the adult dogs of the G3 group the concentration of Al (p <.01) was lower and in the G2 group the concentration of Zn was higher (p <.01) than in the other groups. Cu and Mn concentrations in the hair were higher (p <.01 and p <.05, respectively) in puppies fed G1 and G2 diets in comparison to adult dogs fed G3 and G43 diets. Hair concentrations of K, Li and Na were higher at D60 in comparison with D0 (p <.01). Correlations between concentrations in the hair of Al and Fe, Al and Mg and Fe and Mg were highly significant (p <.01). Present data do not support the use of element concentrations in the hair to assess their nutritional supply but, likely, they can be used in relation to physiological status of the animals. Further studies are required to investigate the factors affecting element concentrations in the hair of dogs. Concentrations of Cu, Mn and Zn in the hair differed between growing and adult dogs; Al concentration in hair was highly correlated with Fe and Mg; Several factors other than nutritional supply regulate element deposition in the hair [ABSTRACT FROM AUTHOR]