1 Scientific RepoRts | 6:18975 | DOI: 10.1038/srep18975 www.nature.com/scientificreports the musk chemical composition and microbiota of Chinese forest musk deer males Diyan Li 1,* , Binlong Chen 1,* , Long Zhang 1,* , Uma Gaur 1 , tianyuan Ma 1 , Hang Jie 2 , Guijun Zhao 2 , Nan Wu 1 , Zhongxian Xu 1 , Huailiang Xu 1 , Yongfang Yao 1 , ting Lian 1 , Xiaolan Fan 1 , Deying Yang 1 , Mingyao Yang 1 , Qing Zhu 1 & Jessica satkoski trask 3 Male musk deer secrete musk from the musk gland located between their naval and genitals. Unmated male forest musk deer generate a greater amount of musk than mated males, potentially allowing them to attract a greater number of females. In this study, we used gas chromatography and mass spectrometry (GC/Ms) to explore musk chemical composition of the musk pods of captive mated and unmated sexually mature Chinese forest musk deer and used next-generation sequencing to intensively survey the bacterial communities within them. Analysis of the chemical composition of the musk showed that unmated males have more muscone and cholesterol. Features of the musk16S rRNA gene showed that mated Chinese forest musk deer have both a greater shannon diversity (p < 0.01) and a greater number of estimated operational taxonomic units than unmated ones; many bacterial genera were overrepresented in unmated Chinese forest musk deer males. Members of these genera might be involved in musk odor fermentation. PICRUSt analysis revealed that metabolic pathways such as aldosterone-regulated sodium reabsorption, metabolism of terpenoids and polyketides, favone and favonol biosynthesis, and isofavonoid biosynthesis were enriched in the musk of unmated Chinese forest musk deer males. Te dwarf musk deer or Chinese forest musk deer (Moschus berezovskii Flerov) is an endangered artiodactyl species native to southern and central China and northernmost Vietnam 1,2 . Males and females are visibly very similar; neither carries antlers, but males are armed with two abnormally long canine teeth (Figure S1) in the upper jaw that are used in fghts with rivals. On the abdomen, the sexually mature males carry the eponymous musk-pod 3,4 , into which a musk gland (Figure S2) secretes the musk, generally described as of the color and consistency of ‘moist gingerbread’ and which appears to serve for attracting the females 5,6 . Its secretion has a specifc musk odor, and therefore the secretion’s chemical composition may be involved in chemical communication, potentially encoding information about sex and maturity 7 . All animals harbor communities of microbes that profoundly afect their biology, ofen in benefcial ways 8,9 . It is also becoming obvious that symbiotic microbes can extend the host’s behavioral phenotypes in benefcial ways, including facilitating their feeding, antipredator, reproductive, and communicative behaviors 10,11 . Te fermen- tation hypothesis for mammalian chemical communication posits that bacteria in the scent glands of mammals generate odorous metabolites used by their hosts for communication and that variation in host chemical signals is a product of underlying variation in the bacterial communities inhabiting the scent glands 12 . Te musk owes its odor to a preponderance of a particular ketone, known as muscone 6 which is generated by the preputial gland (Figure S2). Muscone is claimed to be the sexual attractant for musk deer females 13 . Previous studies have shown that myocardial ketone body metabolism can be regulated by the gut microbiota during nutrient deprivation 14 giving us a hint that there may be interaction between the microbiome and compounds produced by the host, and potentially, musk pod microbiota and musk generation in Chinese forest musk deer. However, little is known about the composition of the microbiota of musk pod of male Chinese forest musk deer. In this study, we used 1 farm Animal Genetic Resources exploration and innovation Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, P.R. China, 61130. 2 Laboratory of Medicinal Animal, chongqing institute of Medicinal Plant Cultivation, Nanchuan, Chongqing, P.R. China, 408435. 3 Department of Anthropology and california national Primate Research center, University of california, Davis, california. * these authors contributed equally to this work. Correspondence and requests for materials should be addressed to Q.Z. (email: zhuqingsicau@163.com) or J.S.T. (email: jsatkosk@gmail.com) Received: 30 July 2015 Accepted: 02 December 2015 Published: 08 January 2016 opeN