Science of the Total Environment 770 2021 145316 Contents lists available at ScienceDirect Science of the Total Environment j o u r n a l h o m e p a g e w w w e l s e v i e r c o m l o c a t e s c i t o t e n v Diet habitat environment and lifestyle conversion affect the gut microbiomes of giant pandas Lei Jin a 1 Yan Huang b 1 Shengzhi Yang a Daifu Wu b Caiwu Li b Wenwen Deng b Ke Zhao a Yongguo He b Bei Li a Guiquan Zhang b Yaowu Xiong b Rongping Wei b Guo Li b Hongning Wu b Hemin Zhang b Likou Zou a a College of Resources Sichuan Agricultural University Chengdu China b Key Laboratory of State Forestry and Grassland Administration SFGA on Conservation Biology of Rare Animals in the Giant Panda National Park the China Conservation and Research Center for the Giant Panda CCRCGP Chengdu China H I G H L I G H T S G R A P H I C A L A B S T R A C T Diet conversion habitat and lifestyle changes could in uence gut microbiota remarkably in GP High ber diets signi cantly increased the diversity of gut bacterial populations of GP Streptococcus Pseudomonas Enterococ cus Lactococcus Acinetobacter and Clos tridium contribute to lignocellulose digestion GM structure in reintroduced GPs con verged to that of wild pandas Article history Received 22 October 2020 Received in revised form 2 January 2021 Accepted 16 January 2021 Available online 22 January 2021 Editor Henner Hollert Keywords Gut microbiota Giant panda Diet conversion Habitat environment Lifestyle a r t i c l e i n f o a b s t r a c t Gut microbiota GM are important for the health of giant pandas GPs in addition to the utilization of bamboo in their diets However it is not fully understood how diet habitat environment and lifestyle contribute to the composition of GM in GP Consequently we evaluated how dietary changes habitat environment conversions and lifestyle shifts in uence the GM of GPs using high throughput sequencing and genome resolved metagenomics The GM of GPs were more similar when their hosts exhibited the same diet High ber diets sig ni cantly increased the diversity and decreased the richness of gut bacterial communities alone or interacted with the age factor p 0 05 The abundances of Streptococcus Pseudomonas Enterococcus Lactococcus Acinetobacter and Clostridium signi cantly increased during diet conversion process Non parametric factorial Kruskal Wallis sum rank test LDA 4 Reconstruction of 60 metagenome assembled genomes MAGs indi cated that these bacteria were likely responsible for bamboo digestion via gene complements involved in cellu lose hemicellulose and lignin degradation While habitat environment may play a more important role in shaping the GM of GP lifestyle can also greatly affect bacterial communities The GM structure in reintroduced GPs notably converged to that of wild pandas Importantly the main bacterial genera of wild GPs could aid in lig nin degradation while those of reintroduced GPs were related to cellulose and hemicellulose digestion Streptococcus Pseudomonas Enterococcus Lactococcus Acinetobacter and Clostridium may contribute to Abbreviations GM gut microbiota GP giant panda CCRCGP China Conservation and Research Center for the Giant Panda OMD only milk diet MBD milk and bamboo diet OBD only bamboo diet OTU operational taxonomic unit MAGs metagenome assembled genomes KEGG Kyoto Encyclopedia of Genes and Genomes CAZys carbohydrate active enzymes PCoA Principal Coordinates Analysis AAs auxiliary activities GHs glycoside hydrolases CEs carbohydrate esterases LDA Linear Discriminant Analysis LEfSe linear discriminant analysis coupled with effect size Corresponding author at Huimin Road No 211 Wenjiang 611130 Chengdu China E mail address zoulikou sicau edu cn L Zou 1 These authors contributed equally to this work https doi org 10 1016 j scitotenv 2021 145316 0048 9697 2021 Elsevier B V All rights reserved L Jin Y Huang S Yang et al Science of the Total Environment 770 2021 145316 lignocellulose digestion in GP The results revealed that diet conversion habitat environment and lifestyle could remarkably in uence the GM of GP In addition results suggested that increasing the ability of lignin degradation with GM may aid to change the GM of reintroduced pandas to resemble those of wild pandas 2021 Elsevier B V All rights reserved 1 Introduction Gut microbiota GM play bene cial roles in the production of en zymes food digestion homeostasis and immune systems of hosts Claesson et al 2012 Round and Mazmanian 2009 Sommer and Backhed 2013 Consequently changes in the composition diversity or abundance of GM are frequently associated with diseases and im mune system problems Evans et al 2013 Zhernakova et al 2016 In addition a considerable body of studies over the past decade have re vealed that host diet stressors and biogeography are major factors that affect GM dynamics Knight and Girling 2003 Versalovic and Relman 2006 Giant pandas Ailuropoda melanoleuca GPs are solitary animals en demic to China and their wildlife population sizes are small Yang et al 2018 Zhang et al 2018 Schaller et al 1985 GPs belong to the order Carnivora and possess the typical carnivorous digestive system yet they are well known for their unique diet comprising bamboo Wei et al 2015 Zhu et al 2011 Interestingly the GP has not evolved any genome encoding enzymes speci c for cellulose digestion despite their unique dietary adaptation Hu et al 2017 Therefore it is not known how GPs can rely on high ber diets characterized by low nutri tional value components It has consequently been hypothesized that GPs rely on symbiotic gut microbial populations to degrade nutritional components of their highly brous diets including cellulose hemicellu loses and lignin which are all key components of their bamboo diet Hu et al 2017 Bamboo fermentation tests using GP gut microbiomes showed that they can degrade lignocellulose Scoma et al 2020 How ever whether this activity contributes to the nutrition of GPs is open to debate An in vitro enzyme activity assay for cellulose and hemicellulose degradation in GP feces showed that GP had the lowest enzyme activity among major herbivores Guo et al 2018 Whether this in vitro result could represent the situation in vivo is still an open question Joaan et al 2014 Zhu et al reported that the gut microbes of GP had genes coding cellulose and hemicellulose digesting enzymes Zhu et al 2011 Zhang et al found that the abundance of the genes encoding hemicellulose digesting enzymes was signi cantly higher in