Mr. Darcy is a dashing dachshund-beagle-terrier mix dog who lives in New York City. When he started having bloody diarrhea on the sidewalk every day, it was a nightmare for poor Mr. Darcy and his family as well. His veterinarian couldn’t figure out what was wrong. He became lethargic. His people were worried. But luckily Mr. Darcy got help from the people who know all about gut health and digestive disorders in pets.

Mr. Darcy was two years old when his digestive symptoms started. Over just a few months, his stools changed from healthy, solid poops to bloody diarrhea. His veterinarian ran various tests but couldn’t pinpoint a reason for the sudden digestive trouble. The treatments he was given—antibiotics, steroids, prescription foods—helped a little, but also had side effects. He was miserable. Then Mr. Darcy’s person, Chris Gonzalez, heard about AnimalBiome.

Chris is a co-founder of Barkly Pets, a company that connects people with reliable local dog walkers through a phone app. The Barkly Pets folks met AnimalBiome at an industry event. From AnimalBiome, Chris learned that an imbalanced gut microbiome might be contributing to Mr. Darcy’s symptoms.

Usually when a dog begins having digestive issues, an imbalanced gut microbiome is at least partially to blame. Sick dogs may be missing some of the normal gut bacteria that are found in healthy dogs, and some of those missing bacteria may perform crucial roles in the digestive system, like combating inflammation and protecting against pathogens.

Mr. Darcy during his sickness. He lost weight and had very low energy, along with bloody diarrhea.

Using the DoggyBiome: Microbiome Tests & Supplement bundle, Chris sent a stool sample from Mr. Darcy to AnimalBiome for analysis. A few weeks later, he received the microbiome test report via email, and it was clear: Mr. Darcy’s gut microbiome was badly out of balance.

AnimalBiome uses a number known as the Diversity Score to reflect how many types of bacteria are present in a sample and how evenly represented they are. Generally speaking, higher Diversity Scores are associated with better gut health. Mr. Darcy’s Diversity Score was 1.2—well below the healthy range for dogs, which is 1.7 and above. Low diversity in the gut microbiome is associated with all kinds of health problems, ranging from diarrhea to anxiety to obesity.

The antibiotics Mr. Darcy took had likely killed off multiple kinds of healthy bacteria in his gut, allowing one group, the Firmicutes, to take over, monopolizing resources that should have supported many different kinds of bacteria. Medications (like antibiotics), diet, and environment can all influence a pet’s microbiome.

When a sick dog is missing some of the important gut bacteria, stool (poop) from healthy dogs can be used to reintroduce them. AnimalBiome’s Gut Microbiome Restoration Supplements commonly referred to as “fecal microbiota transplant ” (FMT) capsules contain a full range of dog-specific bacteria sourced from healthy, carefully screened donor dogs. These capsules can help increase bacterial diversity in a gut microbiome that’s missing important bacteria. And rebalancing the microbiome can restore health to a sick dog’s digestive system.

Mr. Darcy when he was lethargic and battling digestive illness. Here he’s pictured with his family and dog brother Schroeder.

Chris and his fiancee weren’t sure about the fecal transplant capsules at first. “Gut microbiome restoration” sounded so different from the conventional medicine they were used to. But they were desperate to help Mr. Darcy.

They tried the capsules and were thrilled and relieved by the results. According to Chris, “Mr. Darcy’s symptoms quickly improved, and over the course of the treatment, completely disappeared.”

After the full course of FMT capsules, Chris sent a second stool sample back to AnimalBiome. In the comparison of the “before” and “after” samples, it was clear that the bacteria in Mr. Darcy’s gut had changed significantly. His microbiome now looked a lot more like the microbiome of a healthy dog.

In the months since, “Mr. Darcy has been living his best life,” says Chris. His diarrhea hasn’t returned, and he’s been able to transition off the expensive prescription food he was formerly restricted to.

From the analysis of Mr. Darcy’s first sample, it was very clear that bacteria in the Phylum Firmicutes were dominating his gut. As shown in the graph below, this category made up a whopping 99% of his microbiome. (The proportion in healthy dogs is typically about 30%–40%.)

• Firmicutes are a group of bacteria that are common in the digestive tracts of healthy dogs, but at high levels (like 99%), these bacteria are associated with excessive inflammation.
• As is common in cases of low diversity, one group of bacteria had taken over almost the entire microbiome in Mr. Darcy’s gut, making it very difficult for other bacteria to survive there.
• As a result, Mr. Darcy was missing some key dog-specific bacteria, including Fusobacterium, Bacteroides—each of which plays a crucial role in supporting healthy digestion.

Mr. Darcy’s second sample showed a much healthier microbiome than the first and a marked increase in diversity.

• As you can see in the graph above, Mr. Darcy’s proportion of Firmicutes went from 99% down to 36%, a level much more characteristic of a healthy dog.
• His Diversity Score increased to 1.73, which is within the healthy range.
• And most importantly Mr. Darcy now has good poops and is happy and energetic again.

Here are a few more photos of Mr. Darcy and his crew living it up in NYC. A huge thanks to Chris (pictured below), co-founder of Barkly Pets for contributing to this story!

(Of course, cats can suffer from digestive issues too, so AnimalBiome also offers microbiome testing kits and gut restoration supplements for cats.)