Reintroduction training is instrumental in restoring the oral microbiota of giant pandas from "captivity" to "wildness".

Reintroduction programs aim to restore wild populations, yet success is challenged by host microbiome adaptation to natural environments. Here, we characterized the oral microbiota of giant pandas undergoing pre-release training, comparing them to captive and wild conspecifics, to assess training-induced microbial shifts. We found that after one year of reintroduction training, multi-generational captive giant pandas exhibited increased oral microbiome diversity, with community structure, composition, and predicted functions converging toward wild-type profiles. Adaptive changes included reduced relative abundances of Actinobacillus and Bergeyella, and enrichment of Myroides and Psychrobacter. Functionally, these shifts correlated with decreased starch and sucrose, fructose and mannose, and various lipid metabolism pathways, alongside enhanced methane and galactose metabolism which align with the dietary constraints of a singular food source in the wild environment. Our study demonstrates that pre-release training drives oral microbiota convergence toward wild phenotypes, underscoring microbial adaptation as critical for successful captive-to-wild transitions in endangered species.