Gut microbiota dynamics of adult and sub-adult sika deer during reintroduction 重引入过程中成年和亚成年梅花鹿肠道微生物的动态变化

Abstract

Prey populations significantly influence the distribution of top predators. The sika deer (Cervus nippon), a key prey species for the Amur tiger in Northeast China, plays a critical role in the recovery and dispersal of Amur tiger populations. Reintroduction is a pivotal strategy for restoring prey populations, but it presents challenges, especially in terms of adaptation to the natural environment during the natural training process before animals are released. In this study, we sampled six adult and six sub-adult sika deer and employed high-throughput sequencing of the 16S ribosomal RNA gene to investigate changes in gut microbial diversity, composition, and function during natural training. The results showed that adult sika deer had higher gut microbiota diversity compared to sub-adults. However, as natural training progressed, the gut microbial diversity in sub-adults approached that of adults. Additionally, beneficial, fiber-digesting bacteria associated with adaptation to the natural environment tended to increase during nature training in both adult and sub-adult sika deer, while pathogenic bacteria tended to decrease. We also compared the metabolic function of the gut microbiota in adult and sub-adult sika deer, which showed that the carbohydrate metabolic function of both adults and sub-adults decreased significantly with natural training, declining more rapidly in sub-adults. Conversely, the lipid metabolic function in sub-adults increased significantly with natural training. Overall, a period of nature training is necessary before reintroducing animals to their natural habitats, and sub-adult sika deer, in particular, exhibit greater adaptability to environmental changes as reflected by their gut microbiota dynamics. These findings offer valuable insights for the reintroduction of sika deer and other ungulates. We recommend incorporating natural training in reintroduction programs and prioritizing sub-adult animals for reintroduction.