Photo taken on Jan. 16 shows a female giant panda named Jin Bao Bao (Lumi), at the Dujiangyan base of the China conservation and research center for the giant pandas, in Dujiangyan city of southwest China's Sichuan province. (Xinhua/Xue Yubin)

A study has shed new light on how bamboo, a highly fibrous plant, provides energy for giant pandas, which have a digestive tract similar to carnivores.

Researchers performed a large-scale metagenome sequencing study of the gut microbiota of giant pandas, which feed almost exclusively on bamboo.

They found that their gut microbiota does not significantly contribute to the degradation of cellulose and lignin, which are abundant in bamboo. The finding suggests that the animals do not depend on cellulose or lignin to obtain energy.

Instead, they rely on starch and hemicelluloses in the plant for energy, researchers said.

Giant pandas have a higher capability of digesting starch than strict carnivores. They develop increasing abilities to digest starch following the dietary transition from breast milk to bamboo, according to the study.

The animals have much higher digestibility for hemicellulose than cellulose, and they prefer bamboo shoots, tender leaves and first-year bamboo, with an abundance of hemicelluloses.

Since sufficient bamboo shoots are important for breeding energy-needs, researchers suggest more attention be paid to protect bamboo shoots during the mating and childbirth season of giant pandas in the wild.

"Giant pandas love bamboo partly because it is everywhere in their habitats, and they have few competitors for the food," said Zhang Wenping, who is the first author of the research paper.

In addition, bamboo has high levels of starch among all woody plants, said Zhang, a researcher with the Chengdu Research Base of Giant Panda Breeding in southwest China's Sichuan Province.

The research paper was published in The ISME Journal earlier this month.