Fecal microbiota composition changes after a BW loss diet in Beagle dogs.

In developed countries, dogs and cats frequently suffer from obesity. Recently, gut microbiota composition in humans has been related to obesity and metabolic diseases. This study aimed to evaluate changes in body composition, and gut microbiota composition in obese Beagle dogs after a 17-wk BW loss program. A total of six neutered adult Beagle dogs with an average initial BW of 16.34 ± 1.52 kg and BCS of 7.8 ± 0.1 points (9-point scale) were restrictedly fed with a hypocaloric, low-fat and high-fiber dry-type diet. Body composition was assessed with dual-energy X-ray absorptiometry scan, before (T0) and after (T1) BW loss program. Individual stool samples were collected at T0 and T1 for the 16S rRNA analyses of gut microbiota. Taxonomic analysis was done with amplicon-based metagenomic results, and functional analysis of the metabolic potential of the microbial community was done with shotgun metagenomic results. All dogs reached their ideal BW at T1, with an average weekly proportion of BW loss of -1.07 ± 0.03% of starting BW. Body fat (T0, 7.02 ± 0.76 kg) was reduced by half (P < 0.001), while bone (T0, 0.56 ± 0.06 kg) and muscle mass (T0, 8.89 ± 0.80 kg) remained stable (P > 0.05). The most abundant identified phylum was Firmicutes (T0, 74.27 ± 0.08%; T1, 69.38 ± 0.07%), followed by Bacteroidetes (T0, 12.68 ± 0.08%; T1, 16.68 ± 0.05%), Fusobacteria (T0, 7.45 ± 0.02%; T1, 10.18 ± 0.03%), Actinobacteria (T0, 4.53 ± 0.02%; T1, 3.34 ± 0.01%), and Proteobacteria (T0, 1.06 ± 0.01%; T1, 1.40 ± 0.00%). At genus level, the presence of Clostridium, Lactobacillus, and Dorea, at T1 decreased (P = 0.028), while Allobaculum increased (P = 0.046). Although the microbiota communities at T0 and T1 showed a low separation level when compared (Anosim's R value = 0.39), they were significantly biodiverse (P = 0.01). Those differences on microbiota composition could be explained by 13 genus (α = 0.05, linear discriminant analysis (LDA) score > 2.0). Additionally, differences between both communities could also be explained by the expression of 18 enzymes and 27 pathways (α = 0.05, LDA score > 2.0). In conclusion, restricted feeding of a low-fat and high-fiber dry-type diet successfully modifies gut microbiota in obese dogs, increasing biodiversity with a different representation of microbial genus and metabolic pathways.

Fat digestibility is reduced in old cats with subnormal cobalamin concentrations.

Fat digestibility is decreased in old cats for unknown reasons. Subclinical gastrointestinal diseases and pancreatic dysfunction, both related to ageing, can affect food digestibility. The aim of the present study was to elucidate the prevalence of subnormal cobalamin concentration and pancreatic disease in old cats and study the relationship between both markers and fat digestibility. A total of sixty-four cats without evident signs of gastrointestinal disease were included and grouped according to age: (1) fifteen middle-aged (MA), aged 3-7 years; and (2) forty-nine old, aged 10-17 years. All cats were tested for serum cobalamin, specific feline pancreatic lipase (fPL) and feline trypsin-like immunoreactivity. Then, sixteen of the old cats were selected and grouped according to cobalamin and fPL concentrations: control (normal cobalamin and fPL); low vitamin B12 (cobalamin <290 ng/l; normal fPL); and high fPL (normal cobalamin; fPL >4 µg/ml). A food digestibility trial with a high-fat diet (21·6 %) was performed. In the old group, cobalamin was lower and fPL higher than in MA cats. Of the old cats (n 49), 14 % had subnormal cobalamin, 8 % had a severe increase in fPL, 2 % had both alterations and 14 % had a slight increase in fPL. By contrast, MA cats did not have cobalamin deficiency or an increase in fPL concentrations. Fat digestibility was lower in low vitamin B12 cats than control cats. Decreased fat digestibility is not present in all old cats but could be a characteristic of subclinical chronic gastrointestinal disease. Cobalamin concentration, as a marker of gastrointestinal disease, could be useful for the routine evaluation of old cats.