ORIGINAL ARTICLE Investigation of the faecal microbiota of geriatric cats J. Jia 1 , N. Frantz 2 , C. Khoo 2 , G.R. Gibson 1 , R.A. Rastall 1 and A.L. McCartney 1 1 Department of Food and Nutritional Sciences, University of Reading, Reading, Berkshire, UK 2 Hill’s Pet Nutrition, Topeka, KS, USA Introduction Ageing has been reported to be associated with a number of changes in the digestive tract of companion animals. Geri- atric cats have been shown to have reduced ability to digest fat and protein (Taylor et al. 1995; Perez-Camargo 2004; Laflamme 2005) and increased daily food intake (Taylor et al. 1995). This might indicate that older cats with com- promised digestive function increase their daily food intake to compensate for reduced ability to digest macronutrients (Harper 1998). Limited information is currently available on the gastrointestinal (GI) microbiota of senior cats, although faecal Bifidobacterium levels were shown to be sig- nificantly lower in elderly cats compared with young and adult cats (Patil et al. 2000). Data from humans, however, have shown that significant microbiological changes are associated with ageing, with both numerical changes and species alteration of the predominant microbiota seen in the elderly population compared with the adult population (Blaut et al. 2002; Hopkins et al. 2002). Metabolic differ- ences have also been reported in elderly people, with reduced amylolytic activity and total short-chain fatty acid levels and increased proteolytic activity (Woodmansey 2007). Nutritional requirements are known to change with age. Feeding senior cats an optimal diet could compensate for declining functional systems of some organs during ageing, and thus improve the quality, and possibly length, of life. One recent study reported that cats eating a diet containing a nutritional blend of antioxidants, prebiotic fibre and polyunsaturated fatty acids lived significantly longer and showed significantly slower deterioration in some clinical health characteristics (e.g. haematology, serum, skin thickness and activity levels) compared with cats fed a control diet (Cupp et al. 2008). Understanding the changes in the microbiota associated with ageing in Keywords denaturing gradient gel electrophoresis, ecology, intestinal microbiology, lactic acid bacteria, veterinary. Correspondence Anne L. McCartney, Department of Food and Nutritional Sciences, University of Reading, Reading RG6 6AP, Berkshire, UK. E-mail: a.l.mccartney@reading.ac.uk 2011 ⁄ 0338: received 26 February 2011, revised 12 May 2011 and accepted 8 June 2011 doi:10.1111/j.1472-765X.2011.03105.x Abstract Aims: Aim of the study was to investigate the faecal microbiota of geriatric cats, as aging affects the nutrient digestibility and metabolic function of the feline intestine. Methods and Results: Twenty 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 c. 40% of total bacteria. Clostridium cluster IX was less predominant (0Æ5% of total bacteria), while the remaining bacterial populations enumerated only accounted for 0Æ2% of total bacteria. Highly diverse microbial profiles were demonstrated for geriatric cats with denaturing gradient gel elec- trophoresis, 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 c. 41% of total bacteria have been detected with the probes employed. Significance and Impact of the 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. Letters in Applied Microbiology ISSN 0266-8254 288 Letters in Applied Microbiology 53, 288–293 ª 2011 The Society for Applied Microbiology ª 2011 The Authors