Giant panda (Ailuropoda melanoleuca) is one of the most famous mammals known for its unique biology. They phylogenetically belong to the family Ursidae (bears) and, therefore, have a carnivore-like gastrointestinal tract. However, bamboo, which is highly fiber-rich and poorly nutritional, is the principal dietary resource for giant pandas. Giant panda genome has no homologs of the cellulase digestive gene, indicating that their bamboo diet may rely on the gut microbiome.

Giant panda is a vulnerable mammal by the IUCN Red List of Threatened Species. They have an extremely narrow range of natural habitats. Human activity has drastically reduced and fragmented their habitat range. The restricted gene flow in wild populations made it difficult to maintain genetic diversity within small populations. For this reason, the ex situ conservation of giant pandas has been important. The number of captive pandas now represents over one-quarter of the total number of worldwide pandas. Therefore, focusing on the gut microbiome of captive giant pandas will support their healthy condition and will also contribute to their successful reintroduction into the wild.

To expand the genetic diversity of captive populations, breeding loans have been implemented between breeding facilities, including Japanese zoos. In the wild, giant pandas feed mainly on the bamboo Arundinaria faberi (Rendle) that grows in their habitat. However, the Japanese zoo provides them with bamboo growing nearby, including nine species of Japanese bamboo (Adventure World, Wakayama). And yet, we have not sufficiently investigated the gut microbes in pandas traveling to Japan.

To understand how Japanese bamboo consumption affects the gut bacteria in these pandas, we continuously collected fecal samples from seven adult pandas at the Adventure World (Wakayama, Japan) once a week from June 2022 to June 2023. The composition of the gut bacteria in these pandas was identified using the 16S ribosome RNA gene sequencing.

Compared to a previous study in China, the gut microbial composition in captive giant pandas in Japan was significantly different from the Chinese captive population. A time series analysis of the gut bacteria dynamics in giant pandas over one year will be conducted. The correlation between the significant changes in the gut bacteria of giant pandas traveling to Japan with the changes in food species will be discussed.