Vulture gut bacterial diversity and ex-situ conservation

Global biodiversity loss and anthropogenic pressures on wildlife populations render ex-situ conservation efforts integral to many species recovery programs. This study builds on recent calls to incorporate microbial research into such programs. It is essential to better understand the influence of husbandry on host microbiomes that are fundamental to animal health and survival. The captive housing of vultures as part of reintroduction programs can be considered microbially impoverished due to strict hygiene maintained by zoos following best practices. Yet, the potentially detrimental impacts of this environmental cleanliness on bird health are rarely, if ever, contemplated. Consequences for gut microbial diversity have certainly not previously been considered in this context.By representing two extremes of captive feeding conditions, we demonstrated that, whilst food preparation appears unlikely to modify vulture gut microbial diversity, the prey type offered plays a significant role. This impact outweighed the influence of aviary, age, sex, and facility. Additionally, the type of vulture species overrode any influence that captive conditions may have exerted. This demonstrates the necessity to avoid inter-specific extrapolations, even among closely related species. We encourage comparative studies within-situ populations as well as investigation of mechanisms and drivers important to the vulture microbiomes.