As shown by Zhihe ZHANG, Director of the Chengdu Research Base of Giant Panda Breeding by 16S rRNA analysis of 121 fecal samples of 45 giant pandas throughout one year, the animals digest on average 12,5 kg of bamboo leaves and stems per day but have an extremely low gut microbiota diversity similar to carnivorous and omnivorous bears. Thus after 2 million years of evolution on a bamboo-based nutrition, their gut microbiota has surprisingly not adapted.
CAS news release May 20, 2015