The Study On Quality Evaluation And Influencing Factors Of Musk Secreted By Captive Forest Musk Deer (Moschus Berezovskii)

Musk is a kind of secretions secreted by male Moschidae animals,which is the important substance for chemical communication.Forest musk deer are the earliest Moschidae animal feed artificially in China,which has a history of over 60 years.In the process of artificial breeding of forest musk deer,the technology of artificial musk extraction in vivo has been developed and applied.In each year,musk collecting work begins at February in Fengxian County,Shaanxi Province.In February 2019,this study spent half a month to investigate and visit forest musk deer farms spreading in 10 regions.During the process of investigation and musk collection,it was found that apart from most normal musk samples,a small part of musk showed different apparent characteristics.Experienced veterinarians and breeders also call this musk an abnormal musk.Abnormal musk can be divided into white musk and black musk.In the early stage of this study,musk was classified and grouped based on its apparent characteristics,such as color,odor and form.After classification,this study carried out chemical composition analysis,bacterial flora analysis and fungal flora analysis on the selected musk samples.The specific contents are as follows:(1)The volatile organic compounds(VOCs)in different types of musk were studied by HS/GC-MS.the VOCs could be classified as alcohols,fatty acids,ketones,esters and other compounds that could not be accurately classified.The content of fatty acids in white musk(WM)was significantly higher than that in normal musk(NM)and black musk(BM)(n = 5,P < 0.05).11 main components were selected by GCMS,among which Muscone,pentadecanal,dehydroepiandrosterone sulfate and lanosterol tosylate had significant differences,and the content of WM group was generally lower than that of normal group(P < 0.01).But the contents of heptadecanal,cholest-3,5-diene,2-cholesterene,4-methyl-3?-cholest-4-en-3-ol,cholesteryl pentafluoropropionate and octadecyl trifluoroacetate in WM group were significantly higher than those in NM group(P < 0.01).The VOCs and dichloromethane extracts in musk were analyzed by non metric multidimensional scale(NMDS)analysis.The VOCs in WM group were not similar to those in NM group,while some in BM group were similar to those in WM group,and some were similar to those in NM group.Similarly,in dichloromethane extract,the similarity between WM group and NM group was low,while that between BM group and the other two groups was similar.The concentrations of steroid hormones in white and BMs were significantly lower than those in normal group(n = 5,P < 0.05),The amino acid composition of different musk was analyzed for the first time,which was divided into free amino acid composition in musk and amino acid composition after hydrolysis.The concentrations of most amino acids in NM group and BM group were higher than WM group(n = 5,P < 0.05).The concentrations of most amino acids in the NM group was higher than that in the BM group.(2)Using 16 S rDNA high-throughput sequencing and bioinformatics analysis,the bacterial flora of three musk groups were analyzed.There are 66235.8 ± 877.1 reads in NM group,67208.8 ± 1885.0 reads in WM group and 68358 ± 890.7 reads in BM group(n = 5,mean ± SE).After species annotation,Firmicutes,Proteobacteria and Actinobacteria were common in three groups of samples at phylum level,and Bacteroidetes accounted for a high proportion in some samples.At genus level,there was no dominant species in NM samples.Corynebacterium₁,Corynebacterium,Pseudomonas,Trueperella,Staphylococcus and Lacticigenium were the maximum species in the BM group.In WM group,Pseudomonas,Porphyromonas,Staphylococcus,Escherichia-Shigella and Corynebacterium₁ were the dominant species.In ? diversity analysis,Shannon index of the NM group was significantly higher than that of the other two groups,and the rank abundance curves showed that the evenness of bacterial species in the NM group was higher than that of the other two groups.(3)In this study,18 S rDNA sequencing analysis of musk was carried out for the first time.Through high-throughput sequencing and bioinformatics analysis,74185.6 ± 1931.0 reads were obtained in NM group,73811.8 ± 1411.6 reads in WM group and 74372.4 ± 1095.3 reads in BM group(n = 5,mean ± SE).After species annotation,Ascomycota was common in the three groups,and their relative abundances were more than 60%.The second highest content is Basidiomycota.In some samples,Mucoromycota,Monoblepharomycota and Mortierellomycota also had a high proportion.The relative abundance of Candida fungi in 12 samples was more than 40%.The dominant microflora was Candida,Cladosporium,Dekkera,Epicoccum and Aspergillus.In the NM group,one of the samples had similar dominant flora to that in the WM group,including Cladosporium,Aspergillus,Agaricus and Verticilliu.In the diversity analysis,the OTU number in the BM group was generally higher than that in the other two groups,the Shannon index indicated that the diversity of fungal flora in the NM group was lower than that in the other two groups.In conclusion,the causes of abnormal musk of forest musk deer need to be further studied.The results showed that the difference between normal musk and abnormal musk was not caused by fungal flora.The bacterial diversity of normal musk was significantly higher than abnormal ones.The diversity of bacterial flora in normal musk is high,which can maintain the steady state of the bacterial flora.It may be the next important work to study the formation of high diversity musk bacterial flora and its relationship with host health.