Overweight and the feline gut microbiome – a pilot study

Compared with lean humans, the gut microbiota is altered in the obese. Whether these changes are due to an obesogenic diet, and whether the microbiota contributes to adiposity is currently discussed. In the cat population, where obesity is also prevalent, gut microbiome changes associated with obesity have not been studied. Consequently, the aim of this study was to compare the gut microbiota of lean cats, with that of overweight and obese cats. Seventy‐seven rescue‐shelter cats housed for ≥3 consecutive days were included in the study. Faecal samples were obtained by rectal swab and, when available, by a paired litter box sample. Body condition was assessed using a 9‐point scoring system. DNA was extracted, and the 16S rRNA gene was amplified with a high‐throughput quantitative real‐time PCR chip. Overweight and obese cats had a significantly different gut microbiota compared to lean cats (p < 0.05), but this finding could not be linked to differences in specific bacterial groups. The rectal samples obtained higher DNA concentration than litter box samples (p < 0.0001). In conclusion, overweight and obese cats seem to have an altered gut microbiome as compared to lean cats.     

Phytate degradation,intestinal microbiota,microbial metabolites and immune values are changed in growing pigs fed diets with varying calcium–phosphorus concentration and fermentable substrates

The present study assessed effects of diets containing varying calcium–phosphorus (CaP) concentration and fermentable substrates on digestibility of diets, intestinal microbiota and immune system using 32 crossbred pigs (initial BW 54.7 kg). In a 2 × 2 factorial arrangement, pigs were fed either a corn–soybean meal (CSB) or corn–field pea (CFP) diet with either low [‐] (4.4 g Ca/kg; 4.2 g total P/kg) or high [+] (8.3 g Ca/kg; 7.5 g total P/kg; supplemented with monocalcium phosphate) CaP content for a period of 9 weeks. In week 8, blood samples were taken, and at the end of the trial, all pigs were euthanized to collect digesta and mesenteric lymphoid tissue. Apparent total tract digestibility (ATTD) of P was greater (p < 0.05) for pigs fed the CaP+ and CFP diets than CaP‐ and CSB diets. The myo‐inositol 1,2,3,4,5,6‐hexakis (dihydrogen phosphate) (InsP₆) concentration in jejunal digesta was higher (p < 0.05) for CaP+ than in CaP‐ fed pigs. In addition, caecal and faecal InsP₅ isomer concentration were greater (p < 0.05) for CSB than CFP diets. In the caecum, gene copy numbers of saccharolytic bacteria, such as Eubacterium rectale and Roseburia spp., as well as SCFA concentration were higher (p < 0.05) for CaP+ than CaP‐ diets. In particular, innate immune cell numbers, such as natural killer cells, dendritic cells, monocytes and neutrophils, were greater (p < 0.05) for CaP+ than CaP‐ fed pigs. Diets high in CaP resulted in higher abundance of potential beneficial bacteria and might promote the first line of defence enhancing the activation of the cellular adaptive immune response, thereby possibly decreasing the risk for intestinal disturbances. These results strongly suggest that both, CaP supply and dietary ingredients differing in fermentability, may beneficially affect gut health through increase in SCFA‐producing bacteria and/or bacteria with anti‐inflammatory properties.     

Structural equation models to disentangle the biological relationship between microbiota and complex traits: Methane production in dairy cattle as a case of study

The advent of metagenomics in animal breeding poses the challenge of statistically modelling the relationship between the microbiome, the host genetics and relevant complex traits. A set of structural equation models (SEMs) of a recursive type within a Markov chain Monte Carlo (MCMC) framework was proposed here to jointly analyse the host–metagenome–phenotype relationship. A non-recursive bivariate model was set as benchmark to compare the recursive model. The relative abundance of rumen microbes (RA), methane concentration (CH₄) and the host genetics was used as a case of study. Data were from 337 Holstein cows from 12 herds in the north and north-west of Spain. Microbial composition from each cow was obtained from whole metagenome sequencing of ruminal content samples using a MinION device from Oxford Nanopore Technologies. Methane concentration was measured with Guardian^® NG infrared gas monitor from Edinburgh Sensors during cow's visits to the milking automated system. A quarterly average from the methane eructation peaks for each cow was computed and used as phenotype for CH₄. Heritability of CH₄ was estimated at 0.12 ± 0.01 in both the recursive and bivariate models. Likewise, heritability estimates for the relative abundance of the taxa overlapped between models and ranged between 0.08 and 0.48. Genetic correlations between the microbial composition and CH₄ ranged from −0.76 to 0.65 in the non-recursive bivariate model and from −0.68 to 0.69 in the recursive model. Regardless of the statistical model used, positive genetic correlations with methane were estimated consistently for the seven genera pertaining to the Ciliophora phylum, as well as for those genera belonging to the Euryarchaeota (Methanobrevibacter sp.), Chytridiomycota (Neocallimastix sp.) and Fibrobacteres (Fibrobacter sp.) phyla. These results suggest that rumen's whole metagenome recursively regulates methane emissions in dairy cows and that both CH₄ and the microbiota compositions are partially controlled by the host genotype.     

Results from the treatment of advanced stage squamous cell carcinoma of the nasal planum in cats, using a combination of intralesional carboplatin and superficial radiotherapy: a pilot study

Six cats with an advanced stage squamous cell carcinoma (SCC) of the nasal planum were treated with a combination of superficial radiotherapy and intralesional carboplatin therapy. This multimodality protocol was well tolerated by the majority of cats and resulted in complete responses in all cats (100%). Median follow‐up for all cats is 268 days, and the median time‐to‐recurrence, time‐to‐progression and overall survival have not yet been reached. Our study, although limited in number of animals and with a relatively short median follow‐up compared to other studies for this disease, suggests that a combination of radiotherapy and intralesional carboplatin is a useful treatment option for an advanced stage SCC of the nasal planum in cats and warrants further application of the multimodality approach presented here.