Here’s How Formula—With a Touch of Fecal Slurry—Helped Asian Elephant Calf Linh Mai Thrive After Her Mother Was Unwilling to Nurse

Early in Asian elephant calf Linh Mai’s life, her gut health needed a little help.  

It is not unusual for newborn animals to have some gastrointestinal issues—their guts are adapting to new foods and the needs of a growing body. Normally, the issues resolve naturally on their own. When Linh Mai’s gut issues did not, her animal care team stepped in.  

Working together, the elephant team, Department of Nutrition Science and Center for Conservation Genomics came up with a plan to help: formula and feces.  

Each mammal species’ milk has different levels of nutrients that meet their infant’s needs, protect them from disease and help them to grow. Here at the Smithsonian’s National Zoo and Conservation Biology Institute, when an animal’s mom is either unwilling or unable to nurse her offspring, we can use a milk replacer formula as a substitute.   

Most animal formulas are modeled after domestic species, including dogs, cats, horses and cows. Some exotic animals can do well on formula(s) that were originally designed for different species that have similar diets and nutritional needs, but many need a more specific formula designed for them.

Elephant milk’s composition is challenging to match using readily available formula. Long before Linh Mai’s birth, we selected a formula designed specifically for Asian elephants to have on hand just in case she was not able to nurse from her mother, Nhi Linh. When Nhi Linh showed aggression towards Linh Mai, we were ready to step in with a bottle.   

However, once hand-rearing began, Linh Mai experienced diarrhea and weight loss. Numerous things can cause these issues in a young mammal. We were concerned the formula might not have provided everything she needed to develop properly. While veterinarians investigated possible medical issues and provided crucial supportive care, Erin made formula adjustments.  

When Linh Mai’s condition didn’t improve and couldn’t be explained by a medical diagnosis, Erin suspected Linh Mai wasn’t able to digest the formula properly. The Nutrition team made the call to switch to a different Asian elephant milk replacer. This critical step turned things around for Linh Mai! We saw rapid improvements in her overall health, energy and weight gains—all evidence the new formula was giving Linh Mai the nutrients she needed.  

While the Nutrition team optimized Linh Mai’s formula, the Center for Conservation Genomics’ team thought about ways to help Linh Mai’s gut microbiome—the microscopic bacteria that help animals digest their food and fight off diseases.  

Gut microbes are critical to an animal’s health. Breaking down food into vital nutrients and energy is one of the most important jobs gut microbes perform. If gut microbiomes become unbalanced, the microbes can no longer help an animal get the nutrients from its diet.  

To help boost Linh Mai’s gut microbiome, we needed feces (poop). Specifically, we needed poop from a healthy baby elephant that could give Linh Mai’s gut the good bacteria she needed to properly digest the formula. This treatment—called a fecal microbiota transplant (FMT)—uses feces from a healthy animal as medicine for a sick animal.  

The feces is first screened for pathogens and parasites to ensure that no bad microbes are being transferred. Once the feces is deemed safe to use as an FMT, it allows healthy gut microbes (e.g., probiotic bacteria) to repopulate the gut of a sick individual.  

It may seem odd that poop can be used as medicine, but it is a practice that is already used by doctors to treat human diseases. In the case of Linh Mai, it was very important that we created an FMT using feces from a healthy baby elephant. The gut microbiomes of baby mammals are set up to digest milk, making them very different from the microbiomes of adult animals. We wanted to ensure we were providing the right ‘baby elephant microbes’ to Linh Mai.  

Our colleagues at Columbus Zoo in Ohio were happy to help. Their Asian elephant calf, a male named Ollie, was healthy, the right age and was drinking his mom’s milk—all of which meant he was a great donor for Linh Mai’s FMT. 

Columbus Zoo collected pounds of fresh feces from Ollie and shipped it frozen with dry ice to Washington, D.C. Sally thawed the samples, separated and strained out the large particles, diluted the mixture and measured out the “fecal slurries” into individual tubes. Then, the animal care team stored them frozen until the time came to add them to Linh Mai’s formula as an FMT. She drank the formula and fecal slurry mixture every four hours around the clock for 14 days.

Linh Mai didn’t seem to mind that there was a little extra something in some of her bottles. 

Throughout this process, the elephant team collected samples of Linh Mai’s poop daily. To track how the calf’s gut microbiome developed over the first few months of her life, Sally used next-generation DNA sequencing techniques to analyze the fecal samples.  

What Sally found confirmed the animal care team’s suspicions. In Linh Mai’s first few weeks, the diversity of her gut microbiome bacteria decreased. This matched the period when she was not digesting her formula well and had loose stools—an indication her gut tract and gut microbiome weren’t functioning at their full potential. 

With the formula changes and FMTs, the diversity of Linh Mai’s gut bacteria increased quickly and dramatically. She began defecating regularly and with appropriate consistency and started to pack on the pounds—a huge relief to all who were involved in her care! 

Many specific bacteria responded positively to the new formula and FMTs. One such bacteria, Akkermansia muciniphila, is known to act as a beneficial probiotic in human babies. In infant guts, it helps break down milk oligosaccharides (milk sugars) and promotes the development of a healthy immune system.  

In humans, Akkermansia muciniphila is found in breastmilk, and it is more common in the guts of breastfed infants compared to formula-fed infants. In Linh Mai, this bacteria was mostly absent from her gut microbiome until she started receiving FMTs from Ollie, who was nursing from his mother.  

Interestingly, Sally also found Akkermansia muciniphila in Nhi Linh’s milk microbiome. Even though Linh Mai was receiving some of Nhi Linh’s milk with her formula, it may not have been enough to transfer certain healthy bacteria. So, Akkermansia muciniphila was likely reinforced by the FMTs and the optimized formula provided the milk sugars that it needed to thrive in Linh Mai’s gut.  

In studying Linh Mai’s poop, we could see this species of bacteria continued to stick around in Linh Mai’s gut even after the FMTs ended. The bacteria successfully colonized her gut microbiome! The adjusted formula was feeding both Linh Mai and the beneficial microbes provided by the FMT. Without those nutrients, Linh Mai and her gut microbes would have had a much harder time recovering from her early issues. Together, the formula and feces helped Linh Mai get her gut back on track. 

Wonder what other animals have feasted upon feces for the good of their health? Check out Why Do Animals Eat Poop? (And Why It Might Be a Good Thing).