Urinary excretion of advanced glycation end products in dogs and cats

The present study was conducted with privately owned dogs and cats to investigate whether a relationship exists between the dietary AGEs and the urinary excretion of AGEs, as indication of possible effective absorption of those compounds in the intestinal tract of pet carnivores. For this purpose, data were collected from both raw fed and dry processed food (DPF) fed to dogs and cats, through spot urine sampling and questionnaires. Raw pet food (RF, low in AGE diets) was fed as a primary food source to 29 dogs and DPF to 28 dogs. Cats were categorized into 3 groups, which were RF (n = 15), DPF (n = 14) and dry and wet processed pet food (DWF, n = 25). Urinary-free carboxymethyllysine (CML), carboxyethyllysine (CEL) and lysinoalanine (LAL) were analysed using ultrahigh-performance liquid chromatography (UHPLC)—mass spectrometry, and were standardized for variable urine concentration by expressing the AGE concentrations as a ratio to urine creatinine (Ucr) concentration (µg/µmol Ucr). Urinary excretion of CML, CEL and LAL in dogs fed with DPF was 2.03, 2.14 and 3 times higher compared to dogs fed with RF (p <.005). Similar to the dogs, a significant difference in CML:Ucr, CEL:Ucr and LAL:Ucr between the three diet groups was observed in cats (p-overall < 0.005, ANOVA), in which the RF fed group excreted less AGEs than the other groups. Linear regression coefficients and SE of CML:Ucr, CEL:Ucr and LAL:Ucr showed that body weight and neuter status were significantly correlated with CML and CEL excretion, but not to LAL excretion. Our results revealed a significant correlation between dietary AGEs and urinary excretion of free CML, CEL and LAL, and also showed that endogenous formation of these AGEs occurs in both dogs and cats under physiological conditions.</p

Intestinal health in carnivores

The knowledge on the influence of gastro-intestinal (GI) microbiota on the health status of humans and animals is rapidly expanding. A balanced microbiome may provide multiple benefits to the host, like triggering and stimulation of the immune system, acting as a barrier against possible pathogenic micro-organism, and providing energy and nutritional support. Both culturing methods and more modern molecular techniques have provided valuable insights in gut microbiology of the dog and cat. The major bacterial phyla seem to be similar to those found in other species, with Firmicutes, Bacteroidetes, Proteobacteria, Fusobacteria, and Actinobacteria constituting more than 99% of all gut microbiota. However, the microbiota composition seems to differ substantially on a species/strain level, with much inter-individual variation. Also, studies with diseased and susceptible subjects showed clear alterations in gut microbiome, with a reduced richness of species and dysbiosis as the most commonly found deviations. Several nutritional studies have demonstrated that modulation of canine and feline gut microbiota may occur when the amounts of soluble fibres and macronutrients in the diet are changed. Interestingly, feeding a high protein, low carbohydrate diet to dogs and cats showed clear shifts in bacterial strains, which are normally associated with negative health effects in herbivorous and omnivorous mammals. However, no adverse effects of these bacterial shifts could be noticed in the dog and cat studies. The latter may indicate that species differences are indeed present, possibly driven by nutritional strategies during evolution. Further research is warranted to more thoroughly unravel the mystery of the gut microbiome in general, and that in the carnivorous dog and cat in particular