Gut Microbiome of Healthy and Arthritic Dogs

Abstract

Several studies have underlined the interplay among host-microbiome and pathophysiological conditions of animals. Research has also focused specifically on whether and how changes in the gut microbiome have provoked the occurrence of pathological phenomena affecting cartilage and joints in humans and in laboratory animals. Here, we tried to evaluate the relationship between the gut microbiome and the hip and elbow arthritis in owned dogs. The study included 14 dogs suffering from chronic arthritis (AD) and 13 healthy dogs (HD). After the first visit and during the period of the study, the dogs, under the supervision of the owner, were fed a semi-moist complete diet supplemented with omega 3 fatty acids. Feces and blood samples were collected in the clinic at the first visit (T0) and after days (T45). The plasma C-reactive protein (CRP) was higher, and the serum vitamin B12 and folate concentrations were lower (p < 0.05) in the AD group in comparison to the HD group. Data of the fecal microbiome showed that the relative abundances of the genus Megamonas were higher in AD (p < 0.001), while the relative abundance of the families Paraprevotellaceae, Porphyromonadaceae, and Mogibacteriaceae was significantly lower in comparison to HD. The results of the study identified several bacterial groups that differed significantly in the fecal microbiome between healthy and diseased dogs. If the observed differences in fecal bacterial composition predispose dogs to hip and elbow arthritis or if these differences reflect a correlation with these conditions deserves further investigation.

Keywords: arthritis; dogs; gut microbiome; hematological parameters.

Figure 1

Shannon (H’) and Evenness (J’) indexes of diversity in arthritic (AD) and healthy (HD) dogs. Panel (A) shows mean values at the family level (means were significantly different for p < 0.05 between AD and HD groups). Panel (B) shows mean values at the genus level (means were not significantly different between AD and HD groups). Shannon index was calculated according to the equation H’ = −sum (Pi × ln Pi), where Pi = frequency of every taxon within the sample. The evenness index was calculated as J’ = H’/ln S, where S = total number of taxa within each sample.

Figure 2

Principal coordinate (PCoA) plot representing the beta diversity of the microbial community among dogs’ health status at family (A) and genus (B) level. PCoA was calculated using the Brain Curtis dissimilarity matrix. Dots in red represent arthritic dogs (AD), and dots in blue represent the healthy dogs (HD). The analysis of similarity (ANOSIM) was significant at the family level for p < 0.01.

Figure 3

Bacterial taxa were significantly more abundant in the feces of healthy (HD) and arthritic dogs (AD). The cladogram (A) highlights impactful communities in individuals from each status, and (B) shows the score of the linear discriminant analysis (LDA, significant threshold >2).