Weight-loss in obese dogs promotes important shifts in fecal microbiota profile to the extent of resembling microbiota of lean dogs

Abstract

Background Among the undesirable changes associated with obesity, one possibility recently raised is dysbiosis of the intestinal microbiota. Studies have shown changes in microbiota in obese rats and humans, but there are still few studies that characterize and compare the fecal microbiota of lean, obese and dogs after weight loss. Thus, this study aimed to evaluate the effects of a weight loss program (WLP) in fecal microbiota of dogs in addition to comparing them with those of lean dogs. Twenty female dogs of different breeds, aged between 1 and 9 years were selected. They were equally divided into two groups: Obese group (OG), with body condition score (BCS) 8 or 9/9, and body fat percentage greater than 30%, determined by the deuterium isotope dilution method, and lean group (LG) with BCS 5/9, and maximum body fat of 15%. Weight loss group (WLG) was composed by OG after loss of 20% of their current body weight. Fecal samples were collected from the three experimental groups. Total DNA was extracted from the feces and these were sequenced by the Illumina methodology. The observed abundances were evaluated using a generalized linear model, considering binomial distribution and using the logit link function in SAS (p < 0.05). Results The WLP modulated the microorganisms of the gastrointestinal tract, so that, WLG and LG had microbial composition with greater biodiversity than OG, and intestinal uniformity of the microbiota (Pielou’s evenness index) was higher in OG than WLG dogs (P = 0.0493) and LG (P = 0.0101). In addition, WLG had values of relative frequency more similar to LG than to OG. Conclusion The fecal microbiota of the studied groups differs from each other. The weight loss program can help to reverse the changes observed in obese dogs.

Characterization of intestinal microbiota in normal weight and overweight Border Collie and Labrador Retriever dogs

“…Overall, the dogs’ body condition did not seem to contribute markedly to shaping the faecal microbiota in the current study, a finding in agreement with the results obtained by Handl et al 34 , Forster et al 40 , and Macedo et al 69 Various shifts of diversity indexes have been recorded in other canine obesity-related studies as well 35 , 38 , 41 , 62 , in which dogs were however fed specific diets (e.g., high-protein diets, unequal protein to carbohydrate ratios) that exerted different effects on the GM of obese versus lean animals. Noteworthy variations in the relative frequency of certain bacterial groups were also seen in obese dogs after undergoing a weight loss program 39 , 41 , 69 . An in-depth inspection from phylum to genus level revealed that some taxa (1 phylum, 1 class, 4 families and 7 genera) were significantly affected by body condition, breed, or their interaction, but the real meaning of these findings can barely even be speculated.…”

“…Curiously, compared to LR, BC showed a higher abundance of all significant taxa identified, most of which seem to be involved in obesity development. In previous canine obesity-related studies, an increase in phylum Actinobacteria and genus Roseburia was detected in obese family dogs 34 ; an increase in phylum Actinobacteria has been associated with leaner dogs 35 and dogs that underwent a weight loss program 69 too, however. Higher proportions of Allobaculum have also been linked to both weight loss 41 and excess body weight 62 ; on the contrary, Allobaculum was more abundant in lean dogs than obese dogs or dogs that underwent weight loss in a recent study 69 .…”

“…In previous canine obesity-related studies, an increase in phylum Actinobacteria and genus Roseburia was detected in obese family dogs 34 ; an increase in phylum Actinobacteria has been associated with leaner dogs 35 and dogs that underwent a weight loss program 69 too, however. Higher proportions of Allobaculum have also been linked to both weight loss 41 and excess body weight 62 ; on the contrary, Allobaculum was more abundant in lean dogs than obese dogs or dogs that underwent weight loss in a recent study 69 . Roseburia is a SCFA-producing species believed to possess anti-inflammatory properties 70 , 71 , and it is interesting to note that human and murine studies have shown lower Roseburia spp.…”

“…Surprisingly, faecal undefined Ruminococcaceae were also more abundant in BC. In the study by Kieler et al 39 , Ruminococcaceae relative abundance was lower in dogs showing a faster weight loss rate; similarly, Ruminococcaceae count was highest in obese dogs and lowest in dogs that underwent weight loss in the study by Macedo et al 69 Given the role Ruminococcaceae plays in producing important amounts of acetic and propionic acids, the authors hypothesized that a GM that favours the production of short-chained fatty acids (SCFA) may negatively affect canine weight loss. Many butyrate-producers in the GM actually belong to the family Ruminococcaceae , whose higher concentration in obese mice potentially explains the higher caecal butyrate concentrations observed in the study by Garcia-Mazcorro et al 75 .…”

Obese dogs exhibit different fecal microbiome and specific microbial networks compared with normal weight dogs

“…Several studies have investigated changes in the fecal microbiota in response to the modulation of dietary components, including carbohydrates [14], proteins [15], and fats [16]. In addition, some studies have reported differences in the fecal microbiota of obese dogs after a weight-loss program [17][18][19][20]. Taken together, these studies highlight the importance of the fecal microbiota in sustaining canine health and controlling obesity.…”