With the growing popularity of probiotics, some researchers are asking whether they might benefit felines. A recent, small-scale study investigates.

Probiotic supplements have become increasingly popular in the United States, and a recent study asks whether cats could benefit from them. Though the results hint at certain benefits, the authors call for more work.
Now available in a range of products, including drinks, breakfast cereals, and yogurts, probiotics promise improved digestive and overall health.
However, scientific support for these claims is scant, though research indicates that probiotics can help treat or prevent some specific conditions, such as antibiotic-associated diarrhea.
Regardless of the sizable holes in the evidence, the use of probiotics in the United States quadrupled from 2007 to 2012.
Although scientists are skeptical about the benefits of commercially available food-based probiotics, there is no doubt that the bacteria that reside in the mammalian gut are vital for the health of the gut and beyond.
As the authors of a recent study explain, gut bacteria can boost an animal’s immune defenses, improve digestion, and aid energy metabolism.
Conversely, studies have shown that in cats and dogs, dysbiosis — alterations in the normal gut flora — can cause intestinal inflammation and stress-associated diseases.
Probiotics and fecal quality
Recently, a group of researchers decided to investigate whether a probiotic could influence “nutritional conditions and fecal quality in healthy cats.”
They decided to investigate this topic because, “Although several scientific studies reported beneficial effects of probiotics on gut health in human beings and dogs affected by [gastrointestinal] disorders, few studies on cats have been performed.”
In farmed animals, probiotics are used to increase production and, as the authors explain, there is “an increasing interest in their supplementation in human and companion animals’ diets.”
To investigate, the researchers selected 10 healthy adult Maine Coon cats. The scientists fed all of the animals the same diet, and they gave five of the cats a strain of the bacterium Lactobacillus acidophilus. This species is common in cats, dogs, and humans.
The scientists published their findings in the BMJ journalVet Record Open.
Earlier studies have found that L. acidophilus boosts the performance of egg-laying hens and improves chickens’ gut health.
Assessing improvements
Throughout the 5-week trial, the scientists weighed the cats. They also checked their body condition using the Nutritional Assessment Guidelines for Dogs and Cats, which was designed by the American Animal Hospital Association.
The authors explain that this method is “the most widely used method for assessing cats’ nutritional status.”
The scientists also assessed fecal firmness using the Nestle Purina fecal score system and measured fecal moisture levels in the laboratory. These assessments are considered a good measure of an animal’s gut health.
All of the cats remained healthy throughout the study, with no side effects, and maintained an ideal body composition. Similarly, the scientists found no difference in weight among cats in the control and probiotic groups.
However, the feces of cats in the probiotic group was less moist and of a higher “quality” than that of the control cats. Overall, the authors conclude that “Cats in the [probiotic] group showed drier feces, compared with cats in the [control] group.”
As expected, the feces of the cats in the probiotic group contained higher levels of L. acidophilus, which indicates that the supplementation was having the desired impact.
The feces produced by the felines in the probiotic group also had lower levels of coliform bacteria such as Escherichia coli — indicating, the authors believe, “that probiotics have a slight protective effect on invasive bacteria species.”
Of course, a study involving just 10 cats over a handful of weeks does not provide enough evidence for solid conclusions. Scientists will need to do much more research before they can assess whether there are any true benefits.
It is worth noting that, as the authors write, “The possible causes of soft feces in cats and dogs are still debated.”
Also, all of the animals were healthy and remained so throughout the study; the authors write:
“Further studies with a larger sample of healthy cats and a comparison with cats experiencing [gastrointestinal] pathology could be carried out to investigate the effect of the tested strain on carnivore dysbiotic gut.”
Although the stool quality of the cats in the recent study was improved by some measures of gut health, this does not mean that, overall, the cats who received probiotics were healthier.
As with probiotics for human use, this area needs much more research.