Study On The Characteristics Of Primate Intestinal Flora And The Adaptability Of Macaque Intestinal Flora To Altitud

Gut microbiota,which is the most complex and largest micro-ecological system in animals,is influenced by diet,intestinal morphology and phylogenetic development of host.Meanwhile,the diversity and composition of gut microbiota play an important role in regulating the health,physiology,growth and environmental adaptation of host.Previous studies always focused on one or some primate species’ gut microbiota,while few studies focused on the intestinal microflora of primate species across six major primate lineages from primitive monkeys to modern humans.Meanwhile,environment is also an important factor for gut microbiota.However,the response of gut microbiota to altitude factors in primates is not well documented.In this study,the V4-V5 region of 16 S r RNA in fecal bacteria of 124 individuals of 25 species in 6 primate lineages,including Prosimian monkeys(rosimian Monkey,PM),new world monkeys(New World Monkey,NWM),old world monkeys(Old World Monkey,OWM),lesser ape(Lesser ape,LA),great ape(Great ape,GA)and Human(Human),were amplified and sequenced by using Mi Seq high-throughput sequencing platform.At the same time,the fecal microorganisms of captive macaques from five different elevation zones,including Lasa(LS),Xining(XN),Lanzhou,(LZ),Chengdu(CD)and Nanning(NN)were also sequenced by using Mi Seq high-throughput sequencing platform.(1)Cluster analysis of gut microbiota among 6 primate lineages showed that Human was closer to PM than that to GA.Those results indicated that the gut microbiota could not accurately reflect the evolutionary relationship of the six major primates.This result may be attributed to the interference or masking effect of PM,OWM and Human food factors on the evolutionary relationship.The experiment also showed that NWM,LA,GA and Human could be clustered separately,and 18 species could clearly cluster according to their respective gut microbiota without being affected by different environments of the host.Those results indicated that host genetic background played a leading role in shaping gut microbiota.OWM had the most unique OTU,and Human had the least OTU,and the OTU sharing between the two adjacent groups bacom less along the evolutionary sequence(as the animal evolve from low class to high class),indicating that gut microbiota had more differences along the evolutionary sequence.The richness and diversity of gut microbiota in GA among 6 primate lineages were the highest,while the richness of gut microbiota in Human was the lowest.Meanwhile,For all primates,Firmicutes(51.02%)and Bacteroidetes(36.10%)were the dominant bacteria.Ruminococcaceae(18.99%)and Prevotellaceae(16.10%)were the dominant families in general.The abundance of Ruminococcaceae and Lactobacillaceae in the OWM,LA,GA groups was higher than that in the Human,PM and NWM,while the abundance of Bacteroidaceae and Bacaeroides in PM,Human and NWM was higher than that in other primate lineages.Those results indicated that obvious differences in the diversity and composition of gut microbiota appeared among 6 primate lineages.Human were similar to PM in gut microbiota,proving that the gut microbiota was also strongly regulated by diet.(2)Significant differences in the diversity and composition of gut microbiota were observed between Cercopithecinae and Colobinae.In particular,the gut microbiota of captive Old World monkeys clustered strongly by the two subfamilies.The microbial gut diversity of Colobinae was higher than that of Cercopithecinae.Additionally,abundances of Firmicutes,Lactobacillaceae,Veillonellaceae,and Prevotella were higher in Cercopithecinae than that in Colobinae,while abundances of Bacteroidetes,Ruminococcaceae,Christensenellaceae,Bacteroidaceae,and Acidaminococcaceae were higher in Colobinae.PICRUSt analysis revealed that the predicted metagenomes of metabolic pathways associated with proteins,carbohydrates,and amino acids were significantly higher in Colobinae than that in Cercopithecinae.In the context of host phylogeny,these differences between Cercopithecinae and Colobinae could reflect adaptations associated with their respective diets.(3)Gut microbiota of the Trachypithecus、Rhinopithecus and Colobus in the Colobinae were obviously different.The clustering analysis from OTU could not reflect the evolutionary relationship among the Trachypithecus、Rhinopithecus and Colobus.However,along the evolutionary relationship,some gut microbiota had a gradient of richness.This result indicated that the genetic background may play an important role in changing the composition of gut microbiota.According to the composition of gut microbiota,some different flora appeared among the five genera of Cercopithecinae.It should be noted that the relative abundances of lactobacillus in the five genera exactly decreased in the order from Mandrillus,Macaca,Papio,Cercopithecus to Chlorocebus while Ruminococcaceae increased as the same order.On the whole,on the evolutionary scale of primates,PM,OWM and Huam would be interfered by strong influencing factors and few signals could reflect the development of the whole system.However,some signals could be found on the small evolutionary scale.(4)Studies on the gut microbiota of Macaca mulatta at different altitudes showed that altitude was an important factor influencing the gut microbiota.The OTU richness index of gut microbiota of captive macaques decreased from high elevation to low elevation.The diversity index showed that the diversity of LS and XN captive populations was higher than that of other non-plateau populations.As the elevation decreased,the number of unique OTU also decreased.The high-altitude population had higher gut microbiota diversity and more unique OTU,which may play a positive role in macaque coping with the special environment at high altitude.Furthermore,an obvious difference in the composition of gut microbiota of captive macaques appeared among different elevation zones.The abundance of Ruminococcaceae(41.91%)and Christensenellaceae(7.12%)were the highest in LS.As the elevation decreased,the contents of Ruminococcaceae decreased.Ruminococcaceae could help the host improve the digestive utilization of food,and the short-chain fatty acids generated could regulate host blood pressure to cope with high altitude environment.In addition,some features of gradual changed along the elevation gradient found in functional pathways,such as Cell Motility.That might also be the response of captive macaques to the elevation environment.Therefore,it was speculated that the high abundance of Ruminococcaceae,Christensenellaceae and some functions may play an important role in the adaptation of Macaca mulattas to high altitude environment.