Bacteria in the gut: friends and foes and how to alter the balance

The activities of the bacteria resident in the colon of companion animals can have an impact upon the health of the host. Our understanding of this microbial ecosystem is presently increasing due to the development of DNA-based microbiological tools that allow identification and enumeration of nonculturable microorganisms. These techniques are changing our view of the bacteria that live in the gut, and they are facilitating dietary-intervention approaches to modulate the colonic ecosystem. This is generally achieved by the feeding of either live bacteria (probiotics) or nondigestible oligosaccharides (prebiotics) that selectively feed the indigenous probiotics. Feeding studies with a Lactobacillus acidophilus probiotic have shown positive effects on carriage of Clostridium spp. in canines and on recovery from Campylobacter spp. infection in felines. Immune function was improved in both species. Prebiotic feeding studies with lactosucrose and fructo-oligosaccharides in both cats and dogs have shown positive effects on the microflora balance. Recently synbiotic forms (a probiotic together with a prebiotic) targeted at canines have been developed that show promise as dietary-intervention tools.

Investigation of the faecal microbiota of geriatric cats

Aims: To investigate the faecal microbiota of geriatric cats, as aging affects the nutrient digestibility and metabolic function of the feline intestine. Methods and results: 20 geriatric cats were randomly assigned to two groups that were fed different foods. Coriobacteriaceae, Clostridium cluster XIV, bifidobacteria, and lactic acid bacteria were the dominant faecal bacterial groups, accounting for ∼40% of total bacteria. Clostridium cluster IX was less predominant (0.5% of total bacteria), while the remaining bacterial populations enumerated only accounted for 0.2% of total bacteria. Highly diverse microbial profiles were demonstrated for geriatric cats with denaturing gradient gel electrophoresis, although a few common bands were evident. Some differences were seen in the feline faecal microbiota between animal groups at the same time or over time for individual animals. However, no obvious clustering based on animal group or sample time was indicated. Conclusions: geriatric cats harboured a complex faecal microbiota and ∼41% of total bacteria have been detected with the probes employed. Significance and impact of study: First molecular-based study examining faecal microbiota of geriatric felines. Knowledge of the microbiota associated with ageing in cats may allow improved development of foods specific for the needs of senior cats.