In recent years, the scientific community has become increasingly interested in intestinal microbiota, given that the microorganisms in our digestive tract are endowed with numerous nutritional, metabolic and immune-related faculties.
To better understand how they function, US scientists have turned their attention to the intestinal flora of domestic cats.
Researchers at Ohio State University suggest that domestic cats could help improve our understanding of the potential role gut microbiota may play in the origins and treatment of obesity.
“Animals share our beds, they share our food… things that people do with their pets that highlight they are a naturally occurring disease model with similar environmental exposures as humans,” said lead study author Jenessa Winston, assistant professor of veterinary clinical sciences at the university.
To test their hypothesis, Winston and colleagues put seven overweight cats on a diet for 16 weeks. During the first two weeks of the experiment, the cats were allowed to eat commercially available food specially designed for them.
They were then put on a weight-loss diet for a week, before switching to a low-calorie diet designed to help them lose 1-2% body mass per week.
This penultimate phase lasted 11 weeks. After this, the felines returned to their original maintenance diet.
Throughout the experiment, the researchers took faecal samples to see whether the cats’ different diets had an impact on the production of short-chain fatty acids. These compounds, produced by intestinal bacteria during the fermentation of dietary fibres, are important for metabolism: they provide energy for colon cells, strengthen the intestinal barrier and regulate appetite.
Scientific studies suggest that they are also involved in the prevention of diseases such as obesity, diabetes and inflammatory bowel disorders.
Winston and colleagues found that cats produced more propionic acid when they lost weight on a low-calorie diet. This type of short-chain fatty acid has previously been shown to regulate appetite, reduce fat accumulation, and protect against obesity and diabetes in some mammals.
In their paper, published in the journal Scientific Reports, the researchers explain that the increase in propionic acid is associated with an increase in Prevotella 9 copri, a bacterium that plays a key role in intestinal health.
“When the cats are on the special diet formulated for weight loss, propionic acid goes up and stays high, and then goes back down when they’re put back on the maintenance diet. So it really is a dietary change,” Winston explained.
“This paper highlights that when we calorie-restrict cats that are obese, we can alter their microbial ecosystem.”
In other words, it appears that the array of non-pathogenic bacteria, viruses, parasites and fungi that make up the intestinal microbiota of domestic cats could play a role in the development of obesity.
Studying the intestinal flora of felines could, therefore, provide us with a better understanding of the causes and biological mechanisms contributing to this complex chronic disease, which affects around 16% of (human) adults worldwide.