Seasonal Changes Of Gut Microbiota In Captive Giant Panda And Red Panda And Their Relationship With Bamboo Phyllosphere Microbiota

Giant pandas(Ailuropoda melanoleuca)and red pandas(Ailurus fulgens)are carnivores whose diet is specialized to bamboo,which can be used as a model system for studying the gut microbiota convergent evolution.Gut microbiota plays a vital role in host physiology and health.At present,there have been many studies on the gut microbiota of giant pandas affected by a variety of factors such as diet and season,but few study has focused on seasonal changes of gut microbiota in giant panda and red panda and their bamboo phyllosphere microbiota.In this study,fresh feces and bamboo leaves of captive giant pandas and red pandas were collected from Chongqing Zoo in different seasons,and 16 S r RNA amplicon sequencing technology was used to investigate seasonal changes of gut microbiota in giant panda and red panda and their relationship with bamboo phyllosphere microbiota.The results showed that giant panda and red panda gut microbiota belonged to 24 phyla,60 classes,156 orders,288 families,686 genera and 40 phyla,105 classes,278 orders,520 families,1 335 genera,respectively,and bamboo phyllosphere microbiota belonged to 51 phyla,142 classes,333 orders,602 families,1 473 genera.Proteobacteria and Firmicutes were the dominant bacterial phyla in the gut microbiota of both giant panda and red panda.Proteobacteria,Firmicutes,Bacteroidota and Actinobacteria were the dominant bacterial phyla of bamboo phyllosphere microbiota.Proteobacteria and Firmicutes of giant panda and red panda gut microbiota,and Firmicutes,Bacteroidota and Actinobacteria of phyllosphere microbiota had significant difference among different seasons.The giant panda and red panda gut dominant bacterial genera had significant seasonal differences including Clostridium＿sensu＿stricto＿1,Streptococcus,etc.Similarly,the dominant bacterial genera of bamboo phyllosphere microbiota: Sphingomonas,1174-901-12 and so on had seasonal differences(P<0.05,Kruskal-Wallis H test).The highest Sobs index and Shannon index were found in the bamboo phyllosphere microbiota,followed by gut microbiota of red panda,while the lowest Sobs index and Shannon index were found in the gut microbiota of giant panda.The Sobs index of gut microbiota of giant panda,the Sobs index and Shannon index of gut microbiota of red panda in winter were significantly higher than those in summer,while the Shannon index of gut microbiota of giant panda in winter was significantly lower than that in summer.The Sobs index and Shannon index of bamboo phyllosphere microbiota in summer and autumn were significantly higher than those in spring and winter(P<0.05,Mann-Whitney U test).There were significant differences between gut microbial community structure of giant panda and red panda,and the microbial community structure of giant panda,red panda gut and bamboo leaves among different seasons had significant differences(P<0.05,PERMANOVA).Based on the annotation of COG and KEGG database,it was found that the main functions of gut microbiota of giant panda and red panda,bamboo phyllosphere microbiota were amino acid and carbohydrate transport and metabolism,recombination and repair,etc.Among the dominant pathways enriched in KEGG pathway 3(relative abundance >1%),the relative abundance of carbohydrate metabolism transporters of gut microbiota of giant panda and red panda,bamboo phyllosphere microbiota played a dominant role,and there was significant seasonal differences(P<0.05,Kruskal-Wallis H test).Spearman correlation analysis showed that there was no significant correlation between the dominant bacterial phylum in the gut microbiota of giant panda and the main bacteria phylum of bamboo leaves.Proteobacteria in the gut microbiota of red panda were significantly negatively correlated with Actinobacteria of bamboo leaves,while Firmicutes and Actinobacteria of the gut microbiota were significantly positively correlated with Actinobacteria and Proteobacteria of bamboo leaves.EscherichiaShigella in the gut microbiota of giant panda were significantly negatively correlated with Sphingomonas,and Pseudomonas in the gut microbiota of red panda were significantly negatively correlated with Sphingomonas and Enterobacter of bamboo phyllosphere microbiota(P<0.05,Spearman).The seasonal changes of Sobs index and Shannon index of gut microbiota of giant panda lagged behind that of bamboo phyllosphere microbiota.The seasonal change of Sobs index of red panda gut microbiota lagged behind that of bamboo phyllosphere microbiota.The db-RDA analysis was conducted the top 10 OTU of bamboo phyllosphere microbiota as constraint environmental factor,and it was found that the OTU was significantly correlated with the gut microbiota of giant panda and red panda.The OTU7406(Sphingomonas)and OTU976(Massilia)had the greatest influence on the gut microbiota of giant panda and red panda.In conclusion,captive pandas and red pandas had relatively simple gut microbiota,and their gut microbiota had relatively similar intestinal functions.The composition,diversity community structure and function of gut microbiota were significantly affected by seasonal change,and the effects showed seasonal difference.The staple food bamboo phyllosphere microbiota may be a factor affecting the gut microbiota of giant panda and red panda,and the seasonal stability of gut microbiota community structure and function of captive and red panda can be maintained through appropriate intervention on the microbial community around bamboo leaves.