Tibetan Goat Research Articles

Multi-Omics Approaches Uncovered Critical mRNA–miRNA–lncRNA Networks Regulating Multiple Birth Traits in Goat Ovaries

The goat breeding industry on the Tibetan Plateau faces strong selection pressure to enhance fertility. Consequently, there is an urgent need to develop goat lines with higher fertility and adaptability. The ovary, as a key organ determining reproductive performance, is regulated by a complex transcriptional network involving numerous protein-coding and non-coding genes. However, the molecular mechanisms of the key mRNA–miRNA–lncRNA regulatory network in goat ovaries remain largely unknown. This study focused on the histology and differential mRNA/miRNA/lncRNA between Chuanzhong black goat (CBG, high productivity, multiple births) and Tibetan goat (TG, strong adaptability, single birth) ovaries. Histomorphological analysis showed that the medulla proportion in CBG ovaries was significantly reduced compared to TG. RNA-Seq and small RNA-Seq analysis identified 1218 differentially expressed (DE) mRNAs, 100 DE miRNAs, and 326 DE lncRNAs, which were mainly enriched in ovarian steroidogenesis, oocyte meiosis, biosynthesis of amino acids and protein digestion, and absorption signaling pathways. Additionally, five key mRNA–miRNA–lncRNA interaction networks regulating goat reproductive performance were identified, including TCL1B–novel68_mature–ENSCHIT00000010023, AKAP6–novel475_mature–ENSCHIT00000003176, GLI2–novel68_mature–XR_001919123.1, ITGB5–novel65_star–TCONS_00013850, and VWA2–novel71_mature–XR_001919911.1. Further analyses showed that these networks mainly affected ovarian function and reproductive performance by regulating biological processes such as germ cell development and oocyte development, which also affected the plateau adaptive capacity of the ovary by participating in the individual immune and metabolic capacities. In conclusion, we identified numerous mRNA–miRNA–lncRNA interaction networks involved in regulating ovarian function and reproductive performance in goats. This discovery offers new insights into the molecular breeding of Tibetan Plateau goats and provides a theoretical foundation for developing new goat lines with high reproductive capacity and strong adaptability to the plateau environment.

Prophylactic effects of Tibetan goat kefir on depression-like behaviors in chronic unpredictable stress model through the gut-brain axis.

Depression is a common psychological disorder, and traditional therapeutic drugs often result in side effects such as emesis, dry mouth, headache, dysentery and constipation. Probiotics and goat milk have garnered widespread attention for their ability to modulate immune function and regulate the endocrine system, and for their anti-inflammatory effects. In this work, the effects of Tibetan goat kefir on the behavior, immune status, neuroendocrine response and gut microbiological composition of chronic unpredictable mild stress (CUMS) mouse models were evaluated. The results indicated that Tibetan kefir goat milk significantly alleviated behavioral despair in mice. Furthermore, the results demonstrated that Tibetan kefir goat milk mitigated the inflammatory response in the mice and moderated the hyperactivity of the hypothalamic-pituitary-adrenal axis and the expression of brain-derived neurotrophic factor. Meanwhile, chronic stress-induced gut microbial abnormalities were restored. In addition, the correlation between gut microbiota and nervous system was evaluated. These results explained the potential mechanism of Tibetan kefir in the antidepressant effect on the CUMS model and enriched diets for depressed patients. © 2024 Society of Chemical Industry.

A genome-wide perspective on the diversity and selection signatures in indigenous goats using 53 K single nucleotide polymorphism array.

Tibetan goats, Taihang goats, Jining grey goats, and Meigu goats are the representative indigenous goats in China, found in Qinghai-Tibet Plateau, Western pastoral area, Northern and Southern agricultural regions. Very few studies have conducted a comprehensive analysis of the genomic diversity and selection of these breeds. We genotyped 96 unrelated individuals, using goat 53 K Illumina BeadChip array, of the following goat breeds: Tibetan (TG), Taihang (THG), Jining grey (JGG), and Meigu (MGG). A total of 45 951 single nucleotide polymorphisms were filtered to estimate the genetic diversity and selection signatures. All breeds had a high proportion (over 95%) of polymorphic loci. The observed and excepted heterozygosity ranged from 0.338 (MGG) to 0.402 (JGG) and 0.339 (MGG) to 0.395 (JGG), respectively. Clustering analysis displayed a genetically distinct lineage for each breed, and their Fst were greater than 0.25, indicating that they had a higher genetic differentiation between groups. Furthermore, effective population size reduced in all four populations, indicating a loss of genetic diversity. In addition, runs of homozygosity were mainly distributed in 5-10 Mb. Lastly, we identified signature genes, which were closely related to high-altitude adaptation (ADIRF) and prolificity (CNTROB, SMC3, and PTEN). This study provides a valuable resource for future studies on genome-wide perspectives on the diversity and selection signatures of Chinese indigenous goats.

Markhor-derived Introgression of a Genomic Region Encompassing PAPSS2 Confers High-altitude Adaptability in Tibetan Goats.

Understanding the genetic mechanism of how animals adapt to extreme conditions is fundamental to determine the relationship between molecular evolution and changing environments. Goat is one of the first domesticated species and has evolved rapidly to adapt to diverse environments, including harsh high-altitude conditions with low temperature and poor oxygen supply but strong ultraviolet radiation. Here, we analyzed 331 genomes of domestic goats and wild caprid species living at varying altitudes (high > 3000 m above sea level and low < 1200 m), along with a reference-guided chromosome-scale assembly (contig-N50: 90.4 Mb) of a female Tibetan goat genome based on PacBio HiFi long reads, to dissect the genetic determinants underlying their adaptation to harsh conditions on the Qinghai-Tibetan Plateau (QTP). Population genomic analyses combined with genome-wide association studies (GWAS) revealed a genomic region harboring the 3'-phosphoadenosine 5'-phosphosulfate synthase 2 (PAPSS2) gene showing strong association with high-altitude adaptability (PGWAS = 3.62 × 10-25) in Tibetan goats. Transcriptomic data from 13 tissues revealed that PAPSS2 was implicated in hypoxia-related pathways in Tibetan goats. We further verified potential functional role of PAPSS2 in response to hypoxia in PAPSS2-deficient cells. Introgression analyses suggested that the PAPSS2 haplotype conferring the high-altitude adaptability in Tibetan goats originated from a recent hybridization between goats and a wild caprid species, the markhor (Capra falconeri). In conclusion, our results uncover a hitherto unknown contribution of PAPSS2 to high-altitude adaptability in Tibetan goats on QTP, following interspecific introgression and natural selection.

Nucleotide Variants in TheTLR5 Gene and Promoter Methylation with A Susceptibility to Brucellosis in Chinese Goats

In this study, we aimed to identify genetic variants of the TLR5 gene and the promoter methylation level with a susceptibility to brucellosis in Chinese Saanen dairy goats (SN). We randomly collected 205 genetically unrelated animals from five Chinese goat breeds, including the Saanen dairy goat (SN, n = 67), Tibetan goat (TG, n = 35), Chuannan black goat (CN, n = 30), Meigu goat (MG, n = 37) and the Jianzhou big-ear goat (JZ, n = 36). A blood sample was collected from each individual and used for the detection of brucellosis, TLR5 polymorphism identification and the detection of promoter methylation. In total, twenty-four SNPs were identified in the five investigated breeds. The allele and genotype frequency of the four loci (g.435C&gt;T, g.690G&gt;T, g.978A&gt;G and g.1832A&gt;G) were correlated with a seroprevalence of brucellosis in the SN goats. An r2 linkage disequilibrium (LD) was detected in SN, CN, TG and MG, but not in the JZ goats. Ten methylation sites were detected on the first CpG island with DNA methylation levels ranging from 0.2% to 5.2%, and twenty-two methylation sites were found on the second methylation island with a 2.3% to 12.1% methylation. The methylation levels of the two CpG islands in the healthy SN were significantly higher than those recorded in the brucella -infected SN (p &lt;0.05). Our findings demonstrated that genetic variations and the promoter methylation of TLR5 were associated with a brucellosis risk in SN goats. These results will be helpful for further studies of disease resistance in ruminants.

Gut microbiota-derived metabolites contribute negatively to hindgut barrier function development at the early weaning goat model.

Early weaning induces intestinal injury, leading to a series of long-term symptoms such as inflammation, malabsorption and diarrhea. In this study, we hypothesized that microbes and their metabolites modulate the host's inflammatory response to early weaning stress in a goat model. A total of 18 female Tibetan goat kids (n = 9) were weaned from their mothers at 28 d (D28) and 60 d (D60) postpartum. D60 and D28 groups were fed the same solid diet ad libitum from weaning to 75 d of age. The colonic epithelium was subject to RNA-sequencing, the caecal digesta metabolomics were assessed by liquid chromatography–tandem mass spectrometry (LC-MS/MS), and the caecal microbiota composition was analysed by 16S ribosomal RNA gene sequencing. We found that early weaning substantially increased the colonic pro-apoptotic gene expression of B-cell lymphoma associated X (Bax), caspase-9, and caspase-3, and decreased the expression of zonula occludens-1 (ZO-1) and claudin-1 (P < 0.01). In addition, a significant Bacteroides acidifaciens enrichment was observed in the hindgut of early-weaned goats (P < 0.01), which negatively correlated with lysophosphatidylcholine products. Similarly, the chemokine signaling, IL-17 signaling, and peroxisome proliferators-activated receptor (PPAR) signaling pathways were upregulated in the colonic mucosa of the early-weaned goats. By applying caecal microbiota transplantation from goats to defaunated C57/6J mice, we confirmed that caecal microbiota of D28 goat kids increased the relative abundance of B. acidifaciens and significantly up-regulated the genes of Bax, G protein–coupled receptor (GPR) 109A, GPR 43, fatty acid binding protein 6, nuclear receptor subfamily 1 group H member 3, angiotensin converting enzyme 2, and IL-6 expression (P < 0.05), and decreased ZO-1, and claudin-1 protein expression in the mice jejunum and colon (P < 0.001). These results proposed that the hindgut microbiota and metabolites mediate the barrier function weakening during early weaning, and the relative abundance of B. acidifaciens was negatively correlated with the hindgut barrier gene expression. This study demonstrates how weaning stress can affect key host–microbe interaction regulators in the hindgut, in a lysophosphatidylcholine dependent and independent manner. Furthermore, based on our mice data, these results are transferable to other mammal species.

Sex differences in rumen fermentation and microbiota of Tibetan goat

BackgroundThe gut microbiota play an important role in maintaining host metabolism, the immune system and health, while sex, genotype, diet and health have specific effects on the composition of the gut microbiota. Therefore, to explore the sex differences in the structure and function of rumen microbiota in Tibetan goats, herein we analyzed sex differences in rumen fermentation parameters, rumen microbiota and the expression of genes related to VFA transport in Tibetan goats.ResultsThe results showed that the contents of acetic acid and propionic acid in the rumen of TGM (Tibetan goat male) were significantly higher than those in TGFm (Tibetan goat female) (P < 0.05), and total VFAs was significantly higher in TGM than TGFm (P < 0.05). Expression of the VFA transport-related genes DRA, AE2, MCT-1, NHE1, and NHE2 in the rumen epithelium of TGFm was significantly higher than that in TGM. Analysis of the composition and structure of the rumen microbiota revealed significant sex differences. At the phylum level, Firmicutes and Bacteroidetes were the dominant phyla in Tibetan goats. In addition, Fibrobacteres and Spirochaetes had significantly greater relative abundances in TGFm than in TGM (P < 0.05). At the genus level, the relative abundance of Fibrobacter, Ruminococcus_1 and Pyramidobacter was significantly higher in TGFm than in TGM (P < 0.05). The functional prediction results showed that replication, recombination and repair, RNA processing and modification were mainly enriched in TGFm (P < 0.05).ConclusionsCorrelation analysis revealed significant associations of some rumen microbiota with the fermentation product VFAs and VFA transport-related genes. We concluded that yearling TGM and TGFm have distinct fermentation and metabolism abilities when adapting to the plateau environment, which provides a certain sex reference basis for Tibetan goat adaptation to the plateau environment.

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Prevalence of Blastocystis infection in free-range Tibetan sheep and Tibetan goats in the Qinghai-Tibetan Plateau in China

Blastocystis is one of the most common enteric parasites in humans and domestic animals. For Tibetan sheep and Tibetan goats, the traditional grazing methods still occupy a dominant position, and the close contact between humans and domestic animals increases the risk of infection by Blastocystis between herdsmen and livestock. However, less pertinent information is available for Tibetan sheep or Tibetan goats. In this study, 880 fecal specimens from Tibetan sheep and Tibetan goats were collected from 6 sampling sites in Tibet to test for Blastocystis using the polymerase chain reaction and sequencing analysis of the partial SSU rRNA gene. The infection rate of Blastocystis was 8.55% for Tibetan sheep (53/620) and 8.46% for Tibetan goats (22/260). The genetic analysis of 53 positive samples from Tibetan sheep identified 4 known subtypes (ST4, ST5, ST10, and ST14). Four known subtypes (ST1, ST5, ST6, and ST10) were identified in Tibetan goats. ST10 was the dominant subtype in Tibetan sheep and Tibetan goats, accounting for 65.33% (49/75) of total subtypes. ST1, ST4, ST5, and ST6 were recognized as belonging to zoonotic subtypes. This report provides a detailed data on the prevalence and subtype distribution of Blastocystis in Tibetan sheep and Tibetan goats in Tibet, which enriches the epidemiological data of Blastocystis infection in Tibetan sheep and Tibetan goats in China. Our results indicated that Tibetan sheep and Tibetan goats can be infected with multiple Blastocystis subtypes, including zoonotic subtypes. More research is needed among humans, livestock and wild animals in Tibet to better understand their role in the spread of Blastocystis. And, One Health measures need to be taken to control and prevent its zoonotic transmission.

Taxonomic and functional adaption of the gastrointestinal microbiome of goats kept at high altitude (4800m) under intensive or extensive rearing conditions.

The gut microbiota composition is influenced by the diet as well as the environment in both wild and domestic animals. We studied the effects of two feeding systems on the rumen and hindgut microbiome of semi-feral Tibetan goats kept at high altitude (∼4800m) using 16S rRNA gene and metagenomic sequencing. Intensive drylot feeding resulted in significantly higher zootechnical performance, narrower ruminal acetate: propionate ratios and a drop in the average rumen pH at slaughter to ∼5.04. Hindgut microbial adaption appeared to be more diverse in the drylot group suggesting a higher influx of undegraded complex non-starch polysaccharides from the rumen. Despite their higher fiber levels in the diet, grazing goats exhibited lower counts of Methanobrevibacter and genes associated with the hydrogenotrophic methanogenesis pathway, presumably reflecting the scarce dietary conditions (low energy density) when rearing goats on pasture from extreme alpine environments. These conditions appeared to promote a relevant abundance of bacitracin genes. In parallel, we recognized a significant increase in the abundance of antibiotic resistance genes in the digestive tracts of drylot animals. In summary, this study provides a deeper insight into the metataxonomic and functional adaption of the gastrointestinal microbiome of goats subject to intensive drylot and extensive pasture rearing conditions at high altitude.

Selection Signatures Analysis Reveals Genes Associated with High-Altitude Adaptation in Tibetan Goats from Nagqu, Tibet

Simple SummaryIn the process of domestication, goats have undergone long-term artificial and natural selection, leading to differences among goat breeds and leaving different selection traces on the genome. However, the genetic components underlying high-altitude adaptation remain largely unknown. Here, we genotyped four goat breeds using the Illumina Caprine 50K single nucleotide polymorphism (SNP) Chip. One highland breed (Tibetan goat) compared with three lowland breeds (Huanghuai goat, Taihang goat and Xinjiang goat) to identify the molecular basis of high-altitude adaptation. So, we investigated selection signatures using the di statistic of four goat breeds and some genes in Tibetan goats related to high-altitude adaptation were identified. In addition, q-PCR validated the gene expression level in Tibetan goats and Huanghuai goats. This information may be valuable for the study of the genetic uniqueness of Tibetan goats and increased understanding of the hypoxic adaptation mechanism of Tibetan goats on the plateau. Tibetan goat is an ancient breed, which inhabits the adverse conditions of the plateaus in China. To investigate the role of selection in shaping its genomes, we genotyped Tibetan goats (Nagqu Prefecture, above 4500 m) and three lowland populations (Xinjiang goats, Taihang goats and Huanghuai goats). The result of PCA, neighbor-joining (N-J) tree and model-based clustering showed that the genetic structure between the Tibetan goat and the three lowland populations has significant difference. As demonstrated by the di statistic, we found that some genes were related to the high-altitude adaptation of Tibetan goats. Functional analysis revealed that these genes were enriched in the VEGF (vascular endothelial growth factor) signaling pathway and melanoma, suggesting that nine genes (FGF2, EGFR, AKT1, PTEN, MITF, ENPEP, SIRT6, KDR, and CDC42) might have important roles in the high-altitude adaptation of Nagqu Tibetan goats. We also found that the LEPR gene was under the strongest selection (di value = 16.70), and it could induce upregulation of the hypoxic ventilatory response. In addition, five genes (LEPR, LDB1, EGFR, NOX4 and FGF2) with high di values were analyzed using q-PCR. Among them, we found that LEPR, LDB1 and FGF2 exhibited higher expression in the lungs of the Tibetan goats; LEPR, EGFR and LDB1 exhibited higher expression in the hearts of the Huanghuai goat. Our results suggest that LEPR, LDB1, EGFR and FGF2 genes may be related to the high-altitude adaptation of the goats. These findings improve our understanding of the selection of the high-altitude adaptability of the Nagqu Tibetan goats and provide new theoretical knowledge for the conservation and utilization of germplasm resources.

Diversity and Composition of Rumen Bacteria, Fungi, and Protozoa in Goats and Sheep Living in the Same High-Altitude Pasture.

Simple SummaryTibetan goats and sheep graze together but have different growth performances, immune responses, and feeding preferences in the Tibetan pasture. Rumen microbiota composed of bacteria, fungi, and protozoa are necessary for a healthy ruminant. Therefore, in this study, we comprehensively describe composition and diversity of bacteria, fungi, and protozoa in the high- altitude rumen. Compared with sheep, the bacteria that degrade crude protein and produce volatile fatty acids (VFA) were increased in the rumen of goats (Saccharofermentans and Lachnospiraceae_XPB1014) (p < 0.05). In addition, when compared with goats, the fungi and protozoa that degrade fiber were increased in rumen of sheep (Neocallimastigaceae and Metadinium) (p < 0.05). Furthermore, VFA were significantly increased in the rumen of goats compared with sheep (p < 0.05). The VFA level was consistent with differences in the microbiota composition in the rumen between goats and sheep. Under mixed grazing conditions, goats tend to select a high-crude protein diet that is good for growth, whereas sheep tend to select a high-lignin diet that is difficult to digest. Therefore, the different microbiota in the rumen of goats and sheep may be explained by dietary preference.Environmental adaptation of ruminants was highly related to microbiota in the rumen. To investigate the diversity and composition of bacteria, fungi, and protozoa in the rumen of high-altitude animals, amplicon gene sequencing was performed using rumen fluid samples derived from both Tibetan goats and sheep at the same pasture in a highland (altitude > 4800 m). Between these two species, the ruminal bacteria and fungi were significantly different at multiple taxonomic levels. The alpha diversity of bacteria was significantly high in goats (p < 0.05). One hundred and sixty-four and 29 Operational Taxonomy Units (OTUs) with significant differences were detected in bacteria and fungi, respectively. The abundance of bacteria, fungi, and protozoa in the rumen was characterized at multiple taxonomic levels, and we determined that Firmicutes, Bacteroidetes, Neocallimastigomycota, and Ciliophora were the most abundant bacteria, fungi, and protozoa. The family Neocallimastigaceae and the genus Metadinium had cellulose degradation capacity in the rumen with high abundance, thereby, suggesting that fungi and protozoa played an essential role in rumen fermentation. In addition, by comparing microbiota in the rumen of goats and sheep it was found, that the fiber-degrading fungi genus (Cyllamyces) was increased in the rumen of sheep (p < 0.05) whereas VFA-producing bacteria (Saccharofermentans and Lachnospiraceae_XPB1014) were increased in the rumen of goats (p < 0.05). Interestingly, in the rumen, no differences in protozoa were observed between goats and sheep (p > 0.05). Furthermore, when compared to sheep, level of acetic acid, propionic acid, and total volatile fatty acid (TVFA) were significantly increased in the rumen of goats (p < 0.05). Taken together, these results suggested microbiota in the rumen drive goats to better adapt to high-altitude grazing conditions.

Comparison of the sequences and expression levels of genes related to follicular development and atresia between prolific and nonprolific goat breeds.

This study investigated the variations of the nucleotide sequences and ovarian expression levels of genes related to follicular development and atresia in prolific Jintang black goats and nonprolific Tibetan goats. Eight genes, FSHB, LHB, FSHR, LHCGR, ESR2, B4GANT2, BCL2 and BAX, were examined using reverse transcription‐polymerase chain reaction and quantitative real‐time PCR. The results showed that the nucleotide and deduced amino acid sequences of the LHB and BAX genes were not different, but there was one base change in the FSHR genes between the two breeds. There was one base change in the FSHB gene, which resulted in one amino acid substitution; there were nine base changes in the LHCGR gene, which resulted in five amino acid substitutions; and there were six base changes in the B4GANT2 gene, which resulted in four amino acid substitutions. The expression levels of the FSHR, LHCGR, ESR2, B4GANT2, BCL2 and BAX genes in the ovaries were not different between the two breeds. The plasma concentrations of FSH were not different, but the plasma concentrations of LH, P4 and E2 were lower in prolific Jintang black goats than in nonprolific Tibetan goats (P ˂ 0.05) at 40 hr after removal of the Controlled Internal Drug Release Devices. These results provide some foundations elucidating the endocrine and molecular mechanisms controlling ovulation rate in goats, but these need to be further verified.

Molecular Characterization of Giardia duodenalis and Enterocytozoon bieneusi Isolated from Tibetan Sheep and Tibetan Goats Under Natural Grazing Conditions in Tibet.

In the present study, fecal samples from a total of 620 Tibetan sheep and 260 Tibetan goats from six counties in Tibet were examined by nested PCR. The results showed that the overall infection rates of Giardia duodenalis and Enterocytozoon bieneusi were 0.8% (5/620) and 15% (93/620), respectively, in Tibetan sheep, and 0% (0/260) and 9.6% (25/260), respectively, in Tibetan goats. Based on sequence analysis of the SSU rRNA, tpi, bg, and gdh genes of G.duodenalis, only assemblage E was identified. Based on sequence analysis of the ribosomal internal transcriptional spacer (ITS) region of E. bieneusi, a total of 12 genotypes (three novel and nine known) were detected, and these clustered into two separate phylogenetic groups. Genotypes CHG19, EbpA, EbpC, H, PigEBITS5, and CTS3 clustered into Group 1 with high zoonotic potential, while genotypes BEB6, CHC8, CHG1, I, CTS1, and CTS2 fell within the host-specific Group 2. Ten genotypes were detected in Tibetan sheep, and two genotypes were found in Tibetan goats. The current study indicated that E.bieneusi infections are widespread among these livestock, and Tibetan goats may play an important role as a reservoir of zoonotic E.bieneusi genotypes.

Sequence Characterization of DSG3 Gene to Know Its Role in High-Altitude Hypoxia Adaptation in the Chinese Cashmere Goat.

The Tibetan cashmere goat is one of the main goat breeds used by people living in the plateau. It exhibits the distinct phenotypic characteristics observed in lowland goats, allowing them to adapt to the challenging conditions at high altitudes. It provides an ideal model for understanding the genetic mechanisms underlying high-altitude adaptation and hypoxia-related diseases. Our previous exome sequencing of five Chinese cashmere breeds revealed a candidate gene, DSG3 (Desmoglein 3), responsible for the high-altitude adaptation of the Tibetan goat. However, the whole DSG3 gene (44 kbp) consisting of 16 exons in the goat genome was not entirely covered by the exome sequencing. In this study, we resequenced all the 16 exons of the DSG3 gene in ten Chinese native goat populations. Twenty-seven SNP variants were found between the lowland and highland goat populations. The genetic distance (FST) of significant SNPs between the lowland and highland populations ranged from 0.42 to 0.58. By using correlation coefficient analysis, linkage disequilibrium, and haplotype network construction, we found three non-synonymous SNPs (R597E, T595I, and G572S) in exon 5 and two synonymous SNPs in exons 8 and 16 in DSG3. These mutations significantly segregated high- and low-altitude goats in two clusters, indicating the contribution of DSG3 to the high-altitude hypoxia adaptation in the Tibetan goat.

Comparing KISS1 and GPR54 genes between the two breeds of goats with low and high prolificacy

There is increasing evidence that kisspeptin, the peptide product of KISS1 gene and its receptor (GPR54), regulate reproductive processes through actions on other organs than hypothalamus. Therefore, the study for the first time, was conducted to investigate the nucleotide sequences and mRNA expression levels of KISS1 and GPR54 genes in pituitary, endometrium, ovary and oviduct of prolific Jintang black goat (JTG) and non-prolific Tibetan goat (TBG) during pro-estrus. By RT-PCR strategy, we obtained that the KISS1 cDNA sequence was 408-bp long, encoding a putative peptide of 135 amino acids. The GPR54 cDNA sequence was 244-bp long, encoding a putative peptide of 81 amino acids. There were two base changes in KISS1, and one base change in GPR54, but these base changes did not result in amino acid substitution between these two breeds. Real-time PCR analyses revealed that both KISS1 and GPR54 genes were expressed in all four tissues examined. KISS1 was most highly expressed in pituitary (p<0.05) and its expression was greater in JTG than TBG (p<0.05). In conclusion, a high KISS1 expression level in pituitary of prolific goat breed might be associated with its great litter size.

Identification and expression patterns of adipokine genes during adipocyte differentiation in the Tibetan goat (Capra hircus)

Adipokines are secreted by adipose tissue and play an important role in the regulation of lipid metabolism. However, the information regarding adipokines in goats is limited. PPARγ is a key gene in adipocyte differentiation and activates adipokine genes. Rosiglitazone is a PPARγ agonist and can promote the expression of PPARγ to increase the expression of lipogenesis-related genes. Therefore, investigation of the relationship between rosiglitazone and adipokines will help us to better understand the function of PPARγ in lipid metabolism in Tibetan goats. In this study, we cloned the resistin (RETN), apelin (APLN), fibroblast growth factor 21 (FGF21), and visfatin (NAMPT) genes from non-pregnant female Tibetan goat adipose tissue. APLN and NAMPT were predominantly expressed in the kidney, and FGF21 was expressed at the highest levels in the liver in vivo. In fat tissues, the highest expression levels of FGF21 and RETN were detected in omental fat, whereas their expression in perirenal and subcutaneous fat was extremely weak. APLN and NAMPT were abundantly expressed in omental and subcutaneous fat in vivo. In addition, the four adipokines had different expression profiles during goat adipocyte differentiation in vitro. Oil red O staining showed that rosiglitazone could promote adipocyte differentiation and lipid droplet formation. In addition, rosiglitazone significantly increased the expression of FGF21 and RETN (p<0.05) but decreased the expression of APLN and NAMPT (p<0.05). These results suggest that the four adipocytokine genes may have different roles during goat adipocyte differentiation. And PPARγ could regulate the expression of the four adipokines, but the detailed regulatory mechanism still needs to be elucidated.

Comparative analysis of tissue expression and methylation reveal the crucial hypoxia genes in hypoxia resistant animals

Tibetan goat and Tibetan sheep are species peculiar to Qinghai–Tibetan Plateau which is the highest plateau in the world, and have high hypoxia resistance to the extremely bad environment. Unlike monogastrics, how the genes change responding to hypoxia in ruminants remains unclear. In this study, three healthy animals of Tibetan sheep, Tibetan goat, Chuanzhong goat, and Small-tailed Han sheep were selected. The expression of factor inhibiting hypoxia-inducible factor 1 (FIH 1) hypoxia-inducible factor 1α (HIF-1α), HIF-3α, and erythropoietin (EPO) in various tissues, including heart, liver, lungs, kidney, muscle, and brain, was investigated. The EPO was observed highly expressed in all the tissues of Tibetan goats and Tibetan sheep compared with low-altitude animals, respectively, implied that higher expression of EPO may give the explanation for the hypoxia resistance of plateau animals. Besides, we also cloned the promoters of FIH-1, HIF-1α, HIF-3α, and EPO in goats and sheep, analyzed their core regions...

Identification and comparative analysis of the ovarian microRNAs of prolific and non-prolific goats during the follicular phase using high-throughput sequencing

The kidding rate is one of the most important economic traits for goat production, but the genetic mechanism that is associated with ovulation rate is poorly understood. Recently, increasing evidence has suggested that microRNAs (miRNAs) influence ovarian biological processes. The present study provides the first comparison of the ovarian miRNAs of prolific Jintang black goats (JTGs) and non-prolific Tibetan goats (TBGs) during the follicular phase using RNA-Seq technology. We generated 11.19 million (M) and 11.34 M clean reads from the TBG and JTG libraries, respectively, from which a total of 389 known miRNAs were identified and 142 novel miRNAs were predicted. A total of 191 miRNAs were differentially expressed between the two breeds. Among the 10 most abundant miRNAs, miR-21-5p was defined as differentially expressed miRNA with a higher level in the JTG library than in the TBG library, but the other miRNAs were not different between the breeds. The predicted miRNA-targeted genes were further analyzed by Gene Ontology and KEGG pathway analyses. The results revealed that miR-21, miR-99a, miRNA-143, let-7f, miR-493 and miR-200b may affect follicular development. These findings will increase the current understanding of the role of ovarian miRNAs in the regulation of ovulation rate in goats.

Habitat Variability and Ethnic Diversity in Northern Tibetan Plateau

There are 56 officially-recognized ethnic groups in China. However, the distinct geographic patterns of various ethnic groups in relation to the physical environment in China have rarely been investigated. Based on the geo-referenced physical environmental parameters of 455 Han, Tu, Hui, Salar, Mongolian, and Tibetan communities in Qinghai, we found that the communities could be statistically demarcated by temperature and aridity threshold according to their ethnicity, implying that the geographic distribution of each ethnic group is mediated by the physical environment. We also observed that the habitat of each ethnic group is ecologically compatible with current subsistence strategies. Tibetans settle in cold and humid high-altitude regions owing to the cultivation of highland barley and the breeding of yak, dzo, Tibetan sheep and Tibetan goat. Mongolians survive by animal husbandry in cold and dry grassland areas. Han and Tu people settle in the Huangshui River Valley, which offers relatively humid climate and flat land for agriculture. Hui and Salar people occupy the Yellow River Valley with its relatively arid environment and grassland vegetation suitable for animal breeding. Our findings offer a new perspective in explaining the geographic patterns and the varieties of ethnic groups in China and elsewhere.