According to a study conducted at Illinois University, headed by Kelly Swanson, gut microbiomes are able to flourish in certain types of diets in any species. These microbes start to develop at birth and will cause different effects on the body depending on the microbe's arrangement. Theses microbes have been known to affect the immune system and are linked with metabolic issues, such as obesity in both animals and people. To see if gut microbes are similar to other microbes of different species, a research was done on eight female cats. These cats were fed randomly two different types of diets. Diet A consisted of high protein and low carbohydrates. Diet B consisted of moderate protein and moderate carbohydrates. The female cats were fed their certain diet one month before mating and continued their diet throughout their pregnancy. When the kittens were born, they stayed with their mother until eight weeks of age and were weaned. The kittens were then fed the same diet as their mother. Fecal samples were taken from each kitten to extract the bacterial DNA.

The results showed that kittens fed Diet A had higher levels of proteolytic bacteria that helped break down protein, and Diet B had higher levels of bacteria that broke down carbohydrates. Also, they found that there was a link between diet and psychology. Kittens fed Diet B had high levels of health promoting bacteria such as bifido and lactobacilli bacteria. Bifido bacteria are connected to the levels of gherin in the blood stream, which stimulates appetite. These bacteria also promote gastro-intestinal health. Low levels of these bacteria are known to cause inflammatory bowel disease in people. Lactobacilli bacteria promote the health of the alimentary canal, healthy levels of cholesterol, and blood leptin levels. It also helps to let the body know when to stop eating by giving off signals of being full. The kittens fed Diet A also had the same bacteria, but they had lower amounts in their gut. However, none of the kittens had any health issues throughout the experiment. The research concluded that feline microbes had similarities in microbes of different species and humans.