Adaptive changes in the intestinal microbiota of giant pandas following reintroduction.

The biggest challenge during the reintroduction of captive giant pandas into the wild is their ability to adapt to the natural environment, and the role of gut microbiota in this process remains unknown. Here, the gut microbiota was analyzed and categorized into training, exploration (1-3 months post-release) and stable period (4-6 months post-release) by activity intensity of released pandas. We found that the gut microbiota diversity of pandas was significantly higher during the stable period compared to the training period. Streptococcus was significantly enriched in the training period, but Clostridium became significantly enriched after being released. KEGG functional prediction analysis revealed that during the stable phase, carbohydrate and amino acids metabolism was significantly reduced, while pathways associated with cofactors and vitamins, other amino acids, lipids, nucleotide and energy metabolism were markedly enriched. This suggests that, after a three-month acclimation period, the transformation of the gut microbiota provides reintroduced giant pandas with more diverse energy acquisition strategies suited to the wild environment. This finding highlighted that the first 3 months post-release are a critical exploration period for digestive adaptation to the wild environment, which will help guide the implementation of future monitoring efforts post-release.