Shuqiang Liu

Comparative Analysis of the Gut Microbial Communities in Forest and Alpine Musk Deer Using High-Throughput Sequencing

The gut ecosystem is characterized by dynamic and reciprocal interactions between the host and bacteria. Although characterizing microbiota for herbivores has become recognized as important tool for gauging species health, no study to date has investigated the bacterial communities and evaluated the age-related bacterial dynamics of musk deer. Moreover, gastrointestinal diseases have been hypothesized to be a limiting factor of population growth in captive musk deer. Here, high-throughput sequencing of the bacterial 16S rRNA gene was used to profile the fecal bacterial communities in juvenile and adult alpine and forest musk deer. The two musk deer species harbored similar bacterial communities at the phylum level, whereas the key genera for the two species were distinct. The bacterial communities were dominated by Firmicutes and Bacteroidetes, with the bacterial diversity being higher in forest musk deer. The Firmicutes to Bacteroidetes ratio also increased from juvenile to adult, while the bacterial diversity, within-group and between-group similarity, all increased with age. This work serves as the first sequence-based analysis of variation in bacterial communities within and between musk deer species, and demonstrates how the gut microbial community dynamics vary among closely related species and shift with age. As gastrointestinal diseases have been observed in captive populations, this study provides valuable data that might benefit captive management and future reintroduction programs.

Effects of crowding and sex on fecal cortisol levels of captive forest musk deer

BackgroundRestricted space and close contact with conspecifics in captivity may be stressful for musk deer, as they are highly territorial and solitary in the wild. So we tested the effects of crowding on stress of forest musk deer (Moschus berezovskii) in heterosexual groups, using fecal cortisol analysis as a non-invasive method. 32 healthy adults during non-breeding seasons were chose as our experimental objects. Group 1 was defined as higher crowding condition, with 10-15 m2/deer (6 enclosures, 10♀ and 6♂); group 2 was defined as lower crowding condition, with 23-33 m2/deer (6 enclosures, 10♀ and 6♂). Every enclosure contained 1 male and 3 female. These patterns had been existed for years.ResultsThe results showed that females in lower crowding condition (217.1 ± 9.5 ug/g) had significantly higher fecal cortisol levels than those in higher crowding condition (177.2 ± 12.1 ug/g). Interestingly, crowding seemed have no effect on male fecal cortisol levels (148.1 ± 9.1 ug/g and 140.5 ± 13.3 ug/g, respectively). At both groups, cortisol was significantly lower in males than in females.ConclusionsThese results showed that chronic crowding may affect stress status of captive forest musk deer. The captive environment should consider the space need for musk deer.

Comparative Analysis of the Gut Microbiota Composition between Captive and Wild Forest Musk Deer

The large and complex gut microbiota in animals has profound effects on feed utilization and metabolism. Currently, gastrointestinal diseases due to dysregulated gut microbiota are considered important factors that limit growth of the captive forest musk deer population. Compared with captive forest musk deer, wild forest musk deer have a wider feeding range with no dietary limitations, and their gut microbiota are in a relatively natural state. However, no reports have compared the gut microbiota between wild and captive forest musk deer. To gain insight into the composition of gut microbiota in forest musk deer under different food-source conditions, we employed high-throughput 16S rRNA sequencing technology to investigate differences in the gut microbiota occurring between captive and wild forest musk deer. Both captive and wild forest musk deer showed similar microbiota at the phylum level, which consisted mainly of Firmicutes and Bacteroidetes, although significant differences were found in their relative abundances between both groups. α-Diversity results showed that no significant differences occurred in the microbiota between both groups, while β-diversity results showed that significant differences did occur in their microbiota compositions. In summary, our results provide important information for improving feed preparation for captive forest musk deer and implementing projects where captive forest musk deer are released into the wild.

Recombination and selection in the major histocompatibility complex of the endangered forest musk deer ( Moschus berezovskii )

The forest musk deer (Moschus berezovskii) is a high elevation species distributed across western China and northern Vietnam. Once abundant, habitat loss and poaching has led to a dramatic decrease in population numbers prompting the IUCN to list the species as endangered. Here, we characterized the genetic diversity of a Major Histocompatibility Complex (MHC) locus and teased apart driving factors shaping its variation. Seven DRB exon 2 alleles were identified among a group of randomly sampled forest musk deer from a captive population in the Sichuan province of China. Compared to other endangered or captive ungulates, forest musk deer have relatively low levels of MHC genetic diversity. Non-synonymous substitutions primarily occurred in the putative peptide-binding region (PBR), with analyses suggesting that recombination and selection has shaped the genetic diversity across the locus. Specifically, inter-allelic recombination generated novel allelic combinations, with evidence for both positive selection acting on the PBR and negative selection on the non-PBR. An improved understanding of functional genetic variability of the MHC will facilitate better design and management of captive breeding programs for this endangered species.

Blood transcriptomics of captive forest musk deer ( Moschus berezovskii ) and possible associations with the immune response to abscesses

Forest musk deer (Moschus berezovskii; FMD) are both economically valuable and highly endangered. A problem for FMD captive breeding programs has been the susceptibility of FMD to abscesses. To investigate the mechanisms of abscess development in FMD, the blood transcriptomes of three purulent and three healthy individuals were generated. A total of ~39.68 Gb bases were generated using Illumina HiSeq 4000 sequencing technology and 77,752 unigenes were identified after assembling. All the unigenes were annotated, with 63,531 (81.71%) mapping to at least one database. Based on these functional annotations, 45,798 coding sequences (CDS) were detected, along with 12,697 simple sequence repeats (SSRs) and 65,536 single nucleotide polymorphisms (SNPs). A total of 113 unigenes were found to be differentially expressed between healthy and purulent individuals. Functional annotation indicated that most of these differentially expressed genes were involved in the regulation of immune system processes, particularly those associated with parasitic and bacterial infection pathways.

Comparison of amino acid profiles and metabolic gene expression in muskrat scented glands in secretion and non-secretion season

The scented gland is an organ responsible for producing musk in muskrats. During musk secretion season, the metabolism of glandular cells increases in the scented glands and a large amount of musk is synthesised. In this study, we collected scented gland arterial blood from six healthy adult male muskrats during non-secretion season (November). We also obtained scented gland arterial blood, venous blood, and musk from six healthy adult males during secretion season (March). Qualitative and quantitative analyses of free amino acids in blood and musk were performed with an automated amino acid analyzer. Additionally, we employed RNA sequencing technology to study the expression patterns of amino acid metabolic pathways in scented glands. Amino acid profile analysis indicates that scented glands can concentrate amino acids during secretion season, and transcriptome analysis suggests that some amino acid metabolism-related genes undergo significant seasonal changes. In summary, scented gland amino acid metabolism displays seasonal differences. Elevated amino acid metabolic activity during secretion season sustains the glands’ secretory function.

Regional and seasonal effects on the gastrointestinal parasitism of captive forest musk deer

Parasite infections can cause adverse effects on health, survival and welfare of forest musk deer. However, few studies have quantified the parasite infection status and evaluated the parasite temporal dynamics and differences between breeding centers for captive forest musk deer. The purpose of this study was to assess seasonal and regional effects on the parasite prevalence, shedding capacity, diversity, aggregation and infracommunity to establish baseline data on captive forest musk deer. The McMaster technique was applied to count parasite eggs or oocysts in 990 fecal samples collected at three breeding centers located in Qinling Mountains and Tibetan Plateau during spring, summer, and winter. Five gastrointestinal parasite groups were found in musk deer, and Eimeria spp. were dominant (mean oocysts per gram=1273.7±256.3). A positive correlation between Eimeria spp. and Strongyloides spp. (r=0.336, p<0.001) based on shedding capacity data was found, as well as a negative correlation between Eimeria spp. and Moniezia spp. (r=-0.375, p=0.003). Both seasonal and regional differences in diversity, prevalence, shedding capacity, aggregation and infracommunity were observed for five parasite groups. The low level of aggregation and high shedding capacity of Eimeria spp. and Strongyloides spp. might reflect the contaminated environment, and indicate that host-parasite relationships are unstable. The high degree of aggregation of Trichuris spp., Ascaris spp., and Moniezia spp. also suggests that some individual hosts had less ability to resist pathogens and greater transmission potential than others. These conclusions suggest that a focus on disease control strategies could improve the health of forest musk deer in captivity.

Adiponectin plays a role in energy metabolism for musk secretion in scent glands of muskrats (Ondatra zibethicus)

Adult male muskrats (Ondatra zibethicus) secret musk from their scent glands to attract females for seasonal mating. The goal of the present study was to investigate whether the changes in energy metabolism related to musk secretion during the breeding and non-breeding seasons are mediated by adiponectin. We found that the secretion of musk during the breeding season was markedly greater than that during the non-breeding season. The serum adiponectin concentration measured using an ELISA kit was higher during the breeding season than during the non-breeding season. Glandular cells, interstitial cells, epithelial cells and glandular cavities were detected in scent glands using histological methods. Immunohistochemical methods were used to show that AMP-activated protein kinase-gamma-1 (AMPKG1), and glucose transporter 1 (GLUT1) were more strongly expressed in glandular cells during the breeding season than the non-breeding season, whereas the immunoreactivity for acetyl-CoA carboxylase 1 (ACC1) was stronger during the non-breeding season. Consistent with these qualitative results, RNA-Seq analysis indicated that the expression of AdipoR1 mRNA was not significantly different during the two seasons. However, AMPKG1 and GLUT1 mRNA levels were higher in scent glands during the breeding season than during the non-breeding season, whereas ACC1 mRNA levels notably decreased during the breeding season. These results suggest that greater musk secretion requires additional energy, which may be provided by an adiponectin-mediated increase in β-oxidation and glucose absorption.

Determination of ovarian cyclicity and pregnancy using fecal progesterone in forest musk deer (Moschus berezovskii)

The forest musk deer (FMD, Moschus berezovskii) is a threatened species in China. Although crucial for its artificial breeding management and thus protection, to date, gonadal steroidogenic activity data are unavailable in this species. Thus, the objectives of the present study were to characterize ovarian activity throughout the estrous cycle, non-pregnant luteal phase, and gestation in female FMD. These goals were accomplished using an enzyme immunoassay to measure fecal concentrations of estradiol (E2) and progesterone. Fecal samples were collected from female FMD (aged 3-4 years) for one year, including during breeding and non-breeding seasons. Non-pregnant estrous cycles were recorded in females, based on fecal progesterone concentrations, their overall estrous cycle length was (mean±SEM) 24.3±0.5 days, with 21.6±0.5 days in the luteal phase and 2.7±0.3 days in the inter-luteal phase. Fecal progesterone and E2 concentrations were also measured in females that became pregnant and gave birth after gestating approximately 6 months. Two weeks after becoming pregnant, the average fecal progesterone concentration was significantly greater than that during non-pregnancy. The average fecal progesterone concentrations during pregnancy increased 3.2-fold above non-pregnant concentrations, decreasing to non-pregnant concentrations only after parturition. By contrast, average fecal E2 concentrations during gestation and after parturition were not different from average non-pregnant concentration. In addition, no difference was observed between progesterone concentration in the first month after pregnancy and the value during the luteal phase. However, progesterone concentration during the second month of pregnancy was significantly higher than the value during the luteal phase. In conclusion, monitoring fecal progesterone is an effective method for assessing ovarian function in FMD and will be a useful tool for breeding management and development of assisted reproductive techniques, such as artificial insemination, in this species.

Feeding performance and preferences of captive forest musk deer while on a cafeteria diet

Abstract. We studied feeding intake and food selection of nine captive forest musk deer (Moschus berezovskii) offered 17 species of plants in China. We also determined nutrient characteristics related to plant quality to assess their effect on food selection. Results indicated that forest musk deer exhibited positive selectivity for four species of plants (M. azedarach, M. baccata, K. japonica and C. orbiculatus) and negative selectivity for the remainder. Two plant species with the highest selectivity values accounted for 47.39 % of total food intake; thus, forest musk deer exhibited the strongest preference for these species. Food intake was positively correlated with feeding frequency and duration (r = 0.764, p < 0.005; r = 0.843, p < 0.005) but was not correlated with sniffing frequency or duration. However, olfaction did play an important role in food recognition by the deer. Pearson correlation analysis (data were log10 transformed) indicated that leaf intake was positively correlated with crude protein content (r = 0.708, p = 0.001) and negatively correlated with crude fiber content (r = -0.811, p < 0.001) and ash content (r = -0.496, p = 0.043). In addition, forest musk deer preferred tannin-rich plants with high protein and low fiber. Food intake was also positively correlated with potassium content (r = 0.672, p < 0.005). Our results suggest that forest musk deer is able to positively select high quality food (high protein content) and avoid low quality food (high fiber content). However, the fact that musk deer also prefer tannin-rich food requires further research to gain deeper insight into the underlying mechanisms in the food selection of forest musk deer.