Diet-induced microbial adaptation process of red deer (Cervus elaphus) under different introduced periods

Abstract

Insufficient prey density is a major factor hindering the recovery of the Amur tiger (Panthera tigris altaica), and to effectively restore the Amur tiger, red deer (Cervus elaphus) was released into the Huangnihe National Nature Reserve of Northeast China as the main reinforcement. Differences in feeding and synergistic changes caused by the intestinal microbial communities could impact the adaptation of wildlife following reintroductions into field environments. We analyzed the foraging changes in shaping the intestinal microbial community of the red deer after being released to the Huangnihe National Nature Reserve and screened the key microbial flora of the red deer when processing complex food resources. The feeding and intestinal microbial communities of the red deer were analyzed by plant Deoxyribonucleic acid (DNA) barcoding sequencing and 16S rRNA high-throughput sequencing, respectively. The results showed that there were significant differences in food composition between wild and released groups [released in 2019 (R2): n = 5; released in 2021 (R0): n = 6]; the wild group fed mainly on Acer (31.8%) and Abies (25.6%), R2 fed mainly on Betula (44.6%), R0 had not formed a clear preferred feeding pattern but had certain abilities to process and adapt to natural foods. Firmicutes (77.47%) and Bacteroides (14.16%) constituted the main bacterial phylum of red deer, of which, the phylum Firmicutes was the key species of the introduced red deer for processing complex food resources (p < 0.05). The wild release process significantly changed the intestinal microbial structure of the red deer, making it integrate into the wild red deer. The period since release into the wild may be a key factor in reshaping the structure of the microbial community. This study suggested that the intestinal microbial structure of red deer was significantly different depending on how long since captive deer has been translocated. Individuals that have lived in similar environments for a long time will have similar gut microbes. This is the adaption process of the wildlife to natural environment after wild release, taking into account the gut microbes, and the feeding changes in shaping microbial communities can help introduced red deer match complex food resources and novel field environments.

The gut microbial differences between pre-released and wild red deer: Firmicutes abundance may affect wild adaptation after release

“…To increase the robustness of the results, this study was compared and discussed with the previous research related to wild release of red deer. In 2021, we released 6 red deer individuals into the wild into the Huangnihe National Nature Reserve, and compared with the results of this study, we found that the abundance of Firmicutes in red deer released in 2021 (68.94%) was similar to that of the pre-released individuals (68.23%), and the abundance of Clostridia was significantly lower than that in the wild red deer ( Guo et al, 2022 ). The results of this study were consistent with the results of previous studies, further indicating that the differences in the Firmicutes represented by Clostridia between pre-released and wild red deer.…”

“…A series of studies are urgently needed to protect and restore red deer population. Wild release is gradually becoming a conservation method for wild population recovery, and captive populations have become an important source of wildlife reintroductions and translocations ( IUCN/SSC, 2013 ; Guo et al, 2022 ).…”