Iowa State Professor's Research Helps Endangered Pandas

by Ellen Bombela, College of Agriculture and Life Sciences Communications Service

Stephan Schmitz-Esser has done plenty of research with microorganisms and how they interact with livestock such as cattle, pigs and chickens.

Recently, the associate professor of animal science's work has involved a drastically different species - giant pandas.

Schmitz-Esser has been working with researchers from the Chengdu Research Base for Giant Panda Breeding in Chengdu Sichuan, China, to try to understand how the animals digestively break down their food. The collaboration was funded by the research base and resulted in a journal article published this month in the Journal of the International Society for Microbial Ecology.

The partnership with China was initiated by Paul Shao, an Iowa State University professor in architecture. Shao is president of the Chinese Cultural Center of America, and has worked to form a lasting relationship with the panda research base. The Chinese Cultural Center of America is an organization that promotes closer cultural and trade relationships between America and China/Pacific-rim Asia.

According to Schmitz-Esser, giant pandas are endangered, with only around 2,000 left in the wild. Some of the main goals of the breeding bases are to increase the total number of pandas, increase genetic diversity and conduct research to better understand the pandas' biology and nutritional needs.

Giant pandas' diets are almost entirely made up of bamboo, which contains a high level of cellulose and lignin, similar to wood, so it is very hard to digest.

"The key point is that mammals cannot break down cellulose," said Schmitz-Esser. "Because mammals don't have the enzymes to break down cellulose, this can only be done by microorganisms like bacteria or fungi. So if mammals eat food rich in cellulose, such as bamboo, they are completely dependent on the microorganisms in their gastrointestinal tract to break down the cellulose."

Schmitz-Esser traveled to China and worked with a team to collect fecal samples from pandas living at the research base. They extracted genetic information to try to learn more about how the animal's digestive system functioned.

Pandas spend up to 14 hours a day eating bamboo. The time it takes the food to be digested and pass through them is only about 5-11 hours, which hardly gives the microorganisms in their gastrointestinal tract any time to break down the food.

"What we found is that there is almost no evidence that microbes in the gastrointestinal tract contribute to breaking down the cellulose," Schmitz-Esser said. "This is very surprising since bamboo is all the pandas eat. What the microbes actually do is only to break down easy, ready-to-digest bamboo components."

"This is puzzling from a scientific perspective because it is so inefficient," Schmitz-Esser said. "The microbes just extract part of the food and energy that would be available, which means they have to eat almost all the time and have less time for other activities.

Schmitz-Esser said one of the long-term goals for the research is to possibly create a probiotic for pandas to help improve cellulose degradation. Probiotics are live microorganisms that provide health benefits when consumed.

"The probiotic would help pandas gain more energy from the bamboo, so hopefully they can thrive better," Schmitz-Esser said.

The probiotic is not the only thing that the researchers have to look forward to. Schmitz- Esser said that the Chinese government is also planning a possible panda national park.

"This would give pandas a huge protected habitat in the wild. The aim is to continuously release pandas from the breeding bases into the wild to try and stabilize the entire panda community," Schmitz- Esser said.

Editor's Note: Photos contributed by Stephan Schmitz-Esser

Feb. 16, 2018