Abstract
Gut microbiota (GM) are important for the health of giant pandas
(Ailuropoda melanoleuca, GP), in addition to the utilization of bamboo
in their diets. However, it’s not fully understood how diet conversions
and environmental factors contribute to the compositions of giant panda
GM. Consequently, we evaluated how dietary changes and lifestyle shifts
influence the GM of giant pandas using high-throughput sequencing and
genome-resolved metagenomics. The gut microbial communities of giant
pandas were more similar when their hosts exhibited the same diets or
lifestyles. High fiber diets significantly increased the diversity
(Shannon index) and decreased the richness (Chao1 index) of gut
bacterial communities (p < 0.05). In addition, the abundances
of Streptococcus, Pseudomonas, Enterococcus, Lactococcus, Acinetobacter,
and Clostridium significantly increased with bamboo consumption
(Non-parametric factorial Kruskal-Wallis sum-rank test,
LDA>4). Reconstruction of 60 metagenome-assembled-genomes
(MAGs) indicated that these bacteria were likely responsible for bamboo
digestion via gene complements involved in cellulose, hemicellulose, and
lignin degradation. Further, the biodiversity of GM in wild or
reintroduced pandas were higher than those of wild-training pandas,
especially fungal communities. The GM structure in reintroduced giant
pandas notably converged to that of wild pandas. These results revealed
Streptococcus, Pseudomonas, Enterococcus, Lactococcus, Acinetobacter,
and Clostridium may contribute to lignocellulose digestion in GP.
Captivity generally led to decreased biodiversity of GM in giant pandas.
Adaptations to increased environmental threats or stressors may aid the
conversion of reintroduced giant panda GM to those like wild pandas. In
summary, we indicated that diet and lifestyle could influence GM
remarkably in GP.