Captivity Reduces Diversity and Shifts Composition of the Great Bustard () Microbiome.

Captivity offers protection for endangered species, but for bustards, captive individuals face a higher risk of disease and exhibit lower reintroduction success rates. Changes in the diversity of host bacterial and fungal microbiota may be a significant factor influencing reintroduction success. The great bustard () is a globally recognized endangered bird species. Previous research on the gut microbiota of the great bustard has been limited, hindering effective conservation efforts. Therefore, this study utilized high-throughput sequencing of the 16S rRNA and Internal Transcribed Spacer (ITS) genes to compare the gut bacterial and fungal microbiota of great bustards in different environments. The results revealed a significant decline in alpha diversity and notable changes in microbial community structure in captive environments. Changes in diet and habitat are likely major factors contributing to these shifts. Consequently, managing rescued wild animals by increasing dietary diversity and exposure to natural environmental reservoirs may enhance the success rate of reintroduction efforts.