Intramuscular fat (IMF) is a key determinant of meat quality, influencing tenderness, juiciness, and flavor. Previous studies have reported that the deposition of IMF is controlled by various factors. However, there is a shortage of research exploring the variations in IMF deposition across age groups from a microbial perspective. This study evaluated the differences in IMF deposition between yearling (1-year-old) and mature (4-year-old) Longdong Cashmere goats and analyzed its association with gut microbiota. The results revealed that the IMF content in shoulder meat and blood lipid levels increased with age (p < 0.05). Conversely, the contents of lipoprotein lipase (LPL) in the liver and duodenum significantly decreased with age. Microbial diversity differed between the two age groups, with specific microbiota identified from the gut of goats involved in the lipid metabolism pathway. The concentrations of valeric and isovaleric acids in the rumen, as well as acetic, propionic and isovaleric acids in the colon, were higher in yearling goats than in mature goats (p < 0.05). Spearman correlation analysis of IMF deposition indicators with gut microbiota revealed that, within the rumen, the abundances of CAG-791 and Sodaliphilus were positively correlated with IMF content in shoulder meat and TG levels, while exhibiting a negative correlation with the contents of valeric acids. Furthermore, the abundance of Clostridium_R showed a positive association with IMF content in shoulder meat and with the abundances of CAG-791and Sodaliphilus. In contrast, the abundance of Bact_11 was negatively correlated with IMF content in shoulder meat, TG levels, and the abundances of CAG-791, Sodaliphilus and Clostridium_R. Within the abomasum, the abundances of UMGS and Hylemonella_582308 were correlated with IMF content in the shoulder meat, as well as serum LDL and VLDL levels. This study provides significant insights into the age-dependent gut microbiota associated with intramuscular fat deposition in goats and identifies several potential gut microbiota for further research on their impacts on IMF deposition.

Intramuscular fat (IMF) content determines marbling levels and influences the sensory and edible qualities of livestock meat. Its deposition is influenced by the animal's age and gut microbial community. This study assessed age-related differences in IMF deposition and shifts in gut microbiota between yearlings (1-year-old) and mature (4-year-old) grazing Tan sheep. Then correlations among these factors were examined to investigate the potential role of gut bacteria in IMF deposition. The results demonstrated that mature sheep exhibited higher IMF content in shoulder and rump muscles (p < 0.05), elevated serum lipid levels (p < 0.001), and increased lipolytic enzyme abundances in the liver and pancreas (p < 0.05), compared with yearlings. In contrast, the concentrations of acetate and propionate in ruminal and colonic contents were lower in mature sheep (p < 0.05), despite a higher abundance of lipolytic and synthetic enzymes in colonic content (p < 0.05). Gut microbial diversity differed between age groups, particularly in the rumen and colon, with clear shifts in specific bacterial taxa. Correlation analyses revealed that the abundance of Copromorpha and RUG420 in the colon were positively correlated with IMF content in shoulder and rump muscles, and serum lipid levels (including free fatty acids, FFA; low-density lipoprotein, LDL; high-density lipoprotein, HDL; and very-low-density lipoprotein, VLDL), but negatively correlated with propionate content (|r| > 0.45, FDR < 0.05). Conversely, the abundance of Cryptobacteroides in the colon was negatively correlated with IMF content in shoulder muscle (r < -0.6, FDR < 0.05), and with the levels of triglyceride (TG), LDL, HDL, and VLDL, while showing positive correlations with acetate and propionate contents (r > 0.45, FDR < 0.05). These findings highlight the potential role of specific colon bacteria (Copromorpha, RUG420, and UBA5905) in IMF deposition, identifying them as candidate bacteria for further investigation regarding their effects on meat quality.

The meat quality of sheep and goats differs even within the same age, gender, and farming systems. Intramuscular fat (IMF) content is an important factor affecting the quality of livestock meat because it affects muscle color, tenderness, juiciness, water-holding capacity, and flavor. This study evaluates the differences in IMF deposition characteristics between Longdong cashmere goats and Tan sheep, and also explores the correlations between these variations and the gut microbiota. The results revealed that the IMF contents in shoulder and rump meat, as well as the blood lipid levels, of Longdong cashmere goats were higher than those of Tan sheep (p < 0.05). The content of fatty acid synthase (FAS) in the duodenum of the goats was lower, but the content of hormone-sensitive lipase (HSL) in both the pancreas and duodenum was greater (p < 0.05). The Chao1 and β diversity showed differences between the two breeds, observed not only in the abomasum but also in the colon. The specific microbiota identified from the goats were involved in the lipid metabolism pathway. The concentrations of acetic acid and propionic acid in the colonic and abomasal chyme were decreased in the goats when compared to the sheep (p < 0.05). The contents of FAS in the colonic chyme of the goats were significantly lower, while HSL in the abomasal chyme was significantly higher than that of the sheep. The correlation analysis of IMF deposition with gut microbiota showed that Acetobacter and UBA1711 in the abomasum, as well as Faecousia, WQUU01, UBA5905, and GCA-900066495 in the colon, were positively correlated with the IMF content in shoulder meat and the level of LDL (except for UBA1711), but negatively associated with the content of propionic acid (|r| > 0.45, p < 0.05). This preliminary study has demonstrated that some specific bacteria in the abomasum and colon were associated with IMF deposition, while also providing an indicative reference range for further investigation into the effects of microbes on IMF deposition.

Intramuscular fat (IMF) is one of the key factors affecting the quality of livestock meat, as it is closely related to muscle color, tenderness, juiciness, water-holding capacity and flavor. The IMF deposition is impacted complexly by various factors, including animal breeds, age, feed, and mi-crobiota. Currently, there is a shortage of research exploring the similarities and differences in IMF deposition between goats and sheep from a microbial perspective. Thus, we selected Longdong cashmere goats (n=10) and Tan sheep (n=10) as the subjects of our research, both of which are recognized for their exceptional meat quality traits. Their differences were assessed including the dressing percentage, GR values, IMF content of muscles, lipid levels, FAS and HSL content of di-gestive glands and gut contents, SCFAs content and microbial diversity in the rumen, abomasum and colon. Spearman correlation analysis was conducted to further analyze the relationship be-tween fat deposition, physiological indicators and microbiota. The results showed that the shoul-der and rump IMF content of Longdong cashmere goats was significantly higher than that of Tan sheep (p< 0.05). The overall levels of triglycerides (TG), total cholesterol (TC), free fatty acids, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and very low-density lipoprotein cholesterol (VLDL-C) in goats were notably higher than those found in sheep. (p< 0.05). The content of FASin the duodenum of goats showed a significant decrease (p=0.04), while the content of HSL in both the pancreas (p= 0.04) and duodenum (p< 0.001) exhib-ited a significant increase. The content of FAS, pH values, content of acetic acid, propionic acid, valeric acid and isovaleric acid in colonic chyme of goats were significantly decreased than those of sheep. The HSL content of goat abomasal chyme showed a significant increase (p= 0.004), while the content of acetic acid and propionic acid demonstrated a significant decrease in comparison with those of sheep (p< 0.05). The Chao1 and β diversity in the abomasum and colon varied be-tween Longdong cashmere goats and Tan sheep. Spearman correlation analysis showed that Sele-nomonas_A, Bifidobacterium_388775 and Eubacterium_Q in the abomasum were directly correlated with the shoulder and rump IMF content (|r|> 0.45). UBA5905 and GCA-900066495 in the colon were negatively correlated with the content of acetic acid, propionic acid and isovaleric acid, and positively correlated with shoulder IMF content. This study emphasizes the importance of aboma-sum and colon microbes in IMF deposition in mutton, and offers available strategies to enhance meat quality and its market value.

Growth rate of bovine skeletal muscle has a major impact on beef yield. Cadherin-11 (CDH11) was found to be a potential candidate gene for growth and development in beef cattle. This study confirmed the high expression of CDH11 in bovine longissimus dorsi using a tissue expression analysis. To understand the transcriptional regulation mechanism of CDH11 gene, we constructed a double luciferase vector for the promoter region of CDH11 gene and determined that the core transcriptional regulatory region was located at −129/+55 bp relative to the transcription start site (TSS). In addition, we confirmed that skeletal muscle growth and development-related transcription factor-specific protein 1 (SP1) and glucocorticoid receptor (GR) bind to the CDH11 gene promoter region at −36/−27 bp and −20/−11 bp, respectively, to regulate CDH11 expression. These interactions provide valuable information for understanding the mechanism of transcriptional regulation of the bovine CDH11 gene during muscle growth and development.

Keratins are the main structural protein components of wool fibres, and variation in them and their genes (KRTs) is thought to influence wool structure and characteristics. The PCR–single strand conformation polymorphism technique has been used previously to investigate genetic variation in selected coding and intron regions of the type II sheep keratin gene KRT81, but no variation was identified. In this study, we used the same technique to explore the 5′ untranslated region of KRT81 and detected three sequence variants (A, B and C) that contain four single nucleotide polymorphisms. Among the 389 Merino × Southdown cross sheep investigated, variant B was linked to a reduction in clean fleece weight, while C was associated with an increase in both greasy fleece weight and clean fleece weight. No discernible effects on staple length or mean-fibre-diameter-related traits were observed. These findings suggest that variation in ovine KRT81 might influence wool growth by changing the density of wool follicles in the skin, the density of individual fibres, or the area of the skin producing fibre, as opposed to changing the rate of extrusion of fibres or their diameter.

Homobox C13 (Hoxc13) is an important transcription factor in hair follicle cycle development, and its deletion had been found in a variety of animals leading to abnormal hair growth and disruption of the hair follicle system. In this study, we used immunofluorescence, immunohistochemistry, real-time fluorescence quantitative PCR (RT-qPCR), and Kompetitive Allele-Specific PCR (KASP) genotyping to investigate molecular genetic characteristics of the Hoxc13 gene in Gansu alpine fine-wool sheep. The results revealed that Hoxc13 was significantly expressed during both the anagen and catagen phases (p < 0.05). It was found to be highly expressed predominantly in the dermal papillae and the inner and outer root sheaths, showing a distinct spatiotemporal expression pattern. Two single nucleotide polymorphisms (SNPs) in the exon 1 of Hoxc13, both the individual locus genotypes and the combined haplotypes were found to be correlated with wool length (p < 0.05). It was determined the mutations led to changes in mRNA expression, in which higher expression of this gene was related with longer wool length. In summary, this unique spatiotemporal expression pattern of the Hoxc13 gene may regulate the wool length of Gansu alpine fine-wool sheep, which can be used as a molecular genetic marker for wool traits and thus improve the breed.

As an important ruminant on the Qinghai-Tibet Plateau, Tibetan sheep can maintain their population reproduction rate in the harsh high-altitude environment of low temperature and low oxygen, which is related to their special adaptations to the plateau. Microbes (known as “second genomes”) play an important role in the host adaptations. However, there have been no reports on the effects of the interactions among rumen fermentation, the microbiota, and host gene expression on the adaptation of Tibetan sheep to high altitude. In this study, rumen fermentation characteristics, the microbiota, and rumen epithelial gene expression of Tibetan sheep in various months were analyzed. The results show that the rumen fermentation characteristics of Tibetan sheep differed in different months. The total SCFA, acetate, propionate, and butyrate concentrations were highest in Oct and lowest in Jun. The CL activity was highest in Feb, while the ACX activity was highest in Apr. In addition, the diversity and abundance of rumen microbes differed in different months. Bacteroidetes (53.4%) and Firmicutes (27.4%) were the dominant phyla. Prevotella_1 and Rikenellaceae_RC9_gut_group were the dominant genera. The abundance of Prevotella_1 was highest in Jun (27.8%) and lowest in Dec (17.8%). In addition, the expression of CLAUDIN4 and ZO1 was significantly higher in Apr than in Aug and Dec, while the expression of SGLT1 was highest in Aug. Correlation analysis showed that there were interactions among rumen fermentation characteristics, the microbiota, and host gene expression, and the host adjusted the rumen fermentation and microbiota structure according to changes in ambient temperature, to adapt to the plateau environment.

Transforming growth factor beta-1 (TGF-β1) regulates the proliferation of ovarian granulosa cells and participates in follicular development in small-tail Han sheep via the SMAD pathway. However, which additional biological processes and regulatory mechanisms are involved in TGF-β1-mediated regulation of granulosa cell changes remains unknown. In this study, TGF-β1-treated (10 ng/mL) ovarian granulosa cells of small-tail Han sheep were used as the model, RNA-Seq was employed to screen differentially expressed genes (DEGs), and rescue experiments were used to verify selected key pathways. In total, 1179 upregulated and 873 downregulated DEGs were screened using RNA-Seq. Gene Ontology (GO) enrichment analysis showed that the DEGs were mainly involved in the biological processes of cell adhesion, cell migration, cell cycle, cell proliferation and apoptosis, and endocrine regulation. Meanwhile, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis indicated that the DEGs were primarily associated with pathways relating to ECM-receptor interaction, PI3K-AKT, focal adhesion, MAPK, TNF, and FOXO signaling, among others. The addition of doramapimod confirmed that the p38 pathway participates in the TGF-β1-induced proliferation and apoptosis of ovarian granulosa cells as well as the regulation of steroid hormone secretion. These results revealed a novel TGF-β1/p38 pathway-mediated mechanism that induces both the proliferation and apoptosis of ovarian granulosa cells. Our findings provide a basis for better understanding the genetic mechanism of TGF-β1 action in follicle development.

Studies of preadipocyte differentiation and fat deposition in sheep have mainly focused on functional genes, and with no emphasis placed on the role that long non-coding RNAs (lncRNAs) may have on the activity of those genes. Here, the expression profile of lncRNAs in ovine preadipocyte differentiation was investigated and the differentially expressed lncRNAs were screened on day 0 (D0), day 2(D2) and day 8(D8) of ovine preadipocyte differentiation, with their target genes being predicted. The competing endogenous RNA (ceRNA) regulatory network was constructed by GO and KEGG enrichment analysis for functional annotation, and some differentially expressed lncRNAs were randomly selected to verify the RNA-Seq results by RT-qPCR. In the study, a total of 2517 novel lncRNAs and 3943 known lncRNAs were identified from ovine preadipocytes at the three stages of differentiation, with the highest proportion being intergenic lncRNAs. A total of 3455 lncRNAs were expressed at all three stages of preadipocyte differentiation, while 214, 226 and 228 lncRNAs were uniquely expressed at day 0, day 2 and day 8, respectively. By comparing the expression of the lncRNAs between the three stages of differentiation stages, a total of 405, 272 and 359 differentially expressed lncRNAs were found in D0-vs-D2, D0-vs-D8, and D2-vs-D8, respectively. Functional analysis revealed that the differentially expressed lncRNAs were enriched in signaling pathways related to ovine preadipocyte differentiation, such as mitogen-activated protein kinase (MAPK) pathway, the phosphoinositide 3-kinase protein kinase B (PI3K-Akt) pathway, and the transforming growth factor beta (TGF-β) pathway. In summary, lncRNAs from preadipocytes at different stages of differentiation in sheep were identified and screened using RNA-Seq technology, and the regulatory mechanisms of lncRNAs in preadipocyte differentiation and lipid deposition were explored. This study provides a theoretical reference for revealing the roles of lncRNAs in ovine preadipocyte differentiation and also offers a theoretical basis for further understanding the regulatory mechanisms of ovine preadipocyte differentiation.

Keratin-related proteins (KAPs) are structural components of wool fibers and are thought to play a key role in regulating the physical and mechanical properties of fibers. Among all KAP genes (KRTAPs), KRTAP6 gene family (KRTAP6-1, KRTAP6-2, KRTAP6-3, KRTAP6-4, and KRTAP6-5) is a very important member with high polymorphism and notable association with some wool traits. In this study, we used real-time fluorescence quantitative PCR (RT-qPCR) and in situ hybridization to investigate spatiotemporal expression of KRTAP6s. The results revealed that KRTAP6 family genes were significantly expressed during anagen compared to other stages (p < 0.05). And it was found the five genes were expressed predominantly in the dermal papillae, inner and outer root sheaths, and showed a distinct spatiotemporal expression pattern. Also, it was found that KRTAP6-1 and KRTAP6-5 mRNA expression was negatively correlated with wool mean fiber diameter (MFD) and mean staple strength (MSS) (p < 0.05). In summary, the KRTAP6 family genes share a similar spatiotemporal expression pattern. And KRTAP6-1 and KRTAP6-5 may regulate the MFD and MSS of Gansu Alpine fine-wool sheep wool by changing the expression.

After prolonged adaptation to high-altitude environments, Tibetan sheep have developed a robust capacity to withstand hypobaric hypoxia. Compared to low-altitude sheep, various organs and tissues in Tibetan sheep have undergone significant adaptive remodeling, particularly in the lungs. However, whether lambs and adult Tibetan sheep exhibit similar adaptations to high-altitude hypoxia remains unclear. In this study, we selected six lambs (4 months old) and six adult (3 years old) female Tibetan sheep to assess their blood gas indicators, observe lung microstructures, and measure the expression levels of key proteins in the lungs. The results indicated that adult sheep exhibited higher hemoglobin concentrations and finer, denser pulmonary vasculature, which enhanced their oxygen-carrying capacity and increased the surface area available for blood gas exchange, resulting in improved oxygen transfer capacity. Conversely, lambs demonstrated larger lungs relative to their body weight and greater pulmonary vascular volumes, which increased relative pulmonary ventilation and blood flow, thereby enhancing oxygen uptake. These findings suggested that Tibetan sheep employ different adaptation strategies to high-altitude hypoxia at various life stages.

In addition to its association with milk protein synthesis via the Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway, JAK2 also affects milk fat synthesis. However, to date, there have been no reports on the effect of JAK2 on ovine mammary epithelial cells (OMECs), which directly determine milk yield and milk contents. In this study, the coding sequence (CDS) region of ovine JAK2 was cloned and identified and its tissue expression and localization in ovine mammary glands, as well as its effects on the viability, proliferation, and milk fat and casein levels of OMECs, were also investigated. The CDS region of ovine JAK2, 3399 bp in length, was cloned and its authenticity was validated by analyzing its sequence similarity with JAK2 sequences from other animal species using a phylogenetic tree. JAK2 was found to be expressed in six ovine tissues, with the highest expression being in the mammary gland. Over-expressed JAK2 and three groups of JAK2 interference sequences were successfully transfected into OMECs identified by immunofluorescence staining. When compared with the negative control (NC) group, the viability of OMECs was increased by 90.1% in the pcDNA3.1-JAK2 group. The over-expression of JAK2 also increased the number and ratio of EdU-labeled positive OMECs, as well as the expression levels of three cell proliferation marker genes. These findings show that JAK2 promotes the viability and proliferation of OMECs. Meanwhile, the triglyceride content in the over-expressed JAK2 group was 2.9-fold higher than the controls and the expression levels of four milk fat synthesis marker genes were also increased. These results indicate that JAK2 promotes milk fat synthesis. Over-expressed JAK2 significantly up-regulated the expression levels of casein alpha s2 (CSN1S2), casein beta (CSN2), and casein kappa (CSN3) but down-regulated casein alpha s1 (CSN1S1) expression. In contrast, small interfered JAK2 had the opposite effect to JAK2 over-expression on the viability, proliferation, and milk fat and milk protein synthesis of OMECs. In summary, these results demonstrate that JAK2 promotes the viability, proliferation, and milk fat synthesis of OMECs in addition to regulating casein expression in these cells. This study contributes to a better comprehension of the role of JAK2 in the lactation performance of sheep.

Transforming growth factor (TGF)-81 is an important multifunctional cytokine in the TGF-8 signaling pathway, which is involved in the molecular regulation of multiple activities, including follicle development and ovulation in female reproductive physiology. However, the biological function of TGF-81 in follicular development and in regulating the proliferation or apoptosis of granulosa cells in small tail Han sheep remain unclear. In this study, we analyzed the expression levels of TGF-81 in the ovary at the follicular stage in small tail Han sheep. We further examined the effects of TGF-81 on the viability, proliferation, and apoptosis of granulosa cells. Differential expression of TGF-81 at the mRNA and protein levels was detected in the ovaries between the beginning of estrus and at preovulation. Cell Counting Kit-8, 5-ethynyl-2 '-deoxyuridine (EdU) labeling, and flow cytometry assays showed that adding 5 and 10 ng/mL TGF-81 could improve the viability and growth rate, reduce the apoptosis rate, and reduce the expression level of the pro-apoptotic factor Bcl-2-modifying factor (BMF) in granulosa cells. Treatment of 10 ng/mL TGF-81 at all time points (except 72 h) significantly increased the positive rate of EdU labeling compared to that of the control group. RNA interference of SMAD4 reversed the decreased apoptosis rate caused by stimulation with 10 ng/mL TGF-81, accompanied by a corresponding increase in the BMF expression level. Collectively, these results indicate that TGF-81 plays a role in the ovarian follicular-phase activity of small tail Han sheep by inhibiting the apoptosis of sheep granulosa cells through the SMAD4/BMF pathway to promote proliferation and vitality. This study provides new insight into the molecular mechanism underlying TGF-81 function regulation in granulosa cells, suggests a new target for the regulation of follicle development, and expands the new field of animal reproduction regulation technology.

Circular RNA (circRNA) is a type of non-coding RNA generated from back-splicing the reactions of linear RNA. It plays an important role in various cellular and biological processes. However, there are few studies about the regulatory effect of circRNAs on cashmere fiber traits in cashmere goats. In this study, the expression profiles of circRNAs in skin tissue were compared between Liaoning cashmere (LC) goats and Ziwuling black (ZB) goats, with a significant difference in cashmere fiber yield, cashmere fiber diameter, and cashmere fiber color, using RNA-seq. A total of 11,613 circRNAs were expressed in the caprine skin tissue, and their type, chromosomal distribution, and length distribution were characterized. A total of 115 up-regulated circRNAs and 146 down-regulated circRNAs in LC goats were screened compared to ZB goats. The authenticity of 10 differentially expressed circRNAs was validated by detecting their expression levels and the head-to-tail splice junction using RT-PCR and DNA sequencing, respectively. The parent genes of differentially expressed circRNA were mainly enriched in some Gene Ontology (GO) terms and pathways related to cashmere fiber traits, such as the canonical Wnt signaling pathway, which is involved in the regulation of cell promotion, stem cell proliferation, Wnt signaling pathway regulation, epithelial morphogenesis, MAPK signaling pathway, and cell adhesion molecules pathway. Eight differentially expressed circRNAs were further selected to construct a circRNA-miRNA network, and some miRNAs that were previously reported as related to fiber traits were found in the network. This study provides a deep understanding of the roles of circRNAs in the regulation of cashmere fiber traits in cashmere goats and the involvement of differential splicing in phenotypic expression according to breed and region.

The keratin-associated proteins (KAPs) are structural components of wool and hair fibres, with over 90 genes that encode these proteins having been identified in mammalian species. A KAP gene called KRTAP27-1 was recently identified in goats, but the gene has not been reported in the closely related ruminant species sheep. In this study, we used a polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis to find ovine KRTAP27-1 and investigate nucleotide sequence variation in the gene. Our analysis revealed four sequence variants (named A to D) in 399 New Zealand Merino x Southdown-cross sheep. Within these sequence variants there were five single nucleotide polymorphisms (SNPs) in the coding region, including two non-synonymous SNPs. Six genotypes (AA, AB, AC, BB, BC and BD) of KRTAP27-1 were detected, and for the three genotypes with a frequency of over 5.0%, sheep of genotypes AB and BB produced wool of higher mean staple length (MSL) and higher greasy fleece weight (GFW) than sheep of genotype AA. These results suggest that variation in ovine KRTAP27-1 may be affecting wool growth and thus production.

The preadipocytes differentiation is a vital process of lipogenesis; exploring the molecular mechanisms of lipogenesis contributes to improve the meat quality and final commercial income. Lipogenesis has been widely reported in other livestock, but little is known about the gene expression profiles at different stages during preadipocytes differentiation in sheep. In this study, ovine preadipocytes were cultured in vitro and then induced to begin differentiation. Then, the gene expression profiles of preadipocytes collected on day 0 (D0), day 2 (D2), and day 8 (D8) of differentiation were analyzed by RNA-seq technology. According to the findings, 2254 differentially expressed genes (DEGs) were found in D2 vs D0; 1817 DEGs and 1902 DEGs were found in D8 vs D0 and D8 vs D2, respectively. The DEGs were found to be enriched in several biological processes, including focal adhesion, ECM-receptor interaction, PI3K-Akt signaling pathway, steroid biosynthesis, and MAPK signaling pathway, according to Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. The regulatory network of the DEGs related to ovine preadipocytes differentiation was systematically constructed, which showed that hub genes might modulate ovine preadipocytes differentiation. In summary, preadipocyte differentiation is regulated by several key genes, including ACACB, CXCL6, SREBF1, INSIG1, APOE, GJA1, CDH11, SYNE1, PCSK1, S100A4, FN1, PLIN2, CXCL6, FN1, PTX3, and FABP3. This study provides a deeper knowledge of the roles of genes in sheep lipogenesis by revealing global gene expression profiles during preadipocyte differentiation.

Long non-coding RNAs (lncRNAs) play important roles in the growth and development of skeletal muscle. However, there is limited information on goats. In this study, expression profiles of lncRNAs in Longissimus dorsi muscle from Liaoning cashmere (LC) goats and Ziwuling black (ZB) goats with divergent meat yield and meat quality were compared using RNA-sequencing. Based on our previous microRNA (miRNA) and mRNA profiles obtained from the same tissues, the target genes and binding miRNAs of differentially expressed lncRNAs were obtained. Subsequently, lncRNA-mRNA interaction networks and a ceRNA network of lncRNA-miRNA-mRNA were constructed. A total of 136 differentially expressed lncRNAs were identified between the two breeds. Fifteen cis target genes and 143 trans target genes were found for differentially expressed lncRNAs, and they were enriched in muscle contraction, muscle system process, muscle cell differentiation, and p53 signaling pathway. A total of 69 lncRNA-trans target gene pairs were constructed, with close relationship with muscle development, intramuscular fat deposition, and meat tenderness. A total of 16 lncRNA-miRNA-mRNA ceRNA pairs were identified, of which some reportedly associated with skeletal muscle development and fat deposition were found. The study will provide an improved understanding of the roles of lncRNAs in caprine meat yield and meat quality.

[目的]激素调控了奶牛和奶山羊的乳腺生长发育和泌乳,但目前在绵羊中的研究还不够全面和系统.[方法]以小尾寒羊为研究对象,在空怀期、妊娠早期、妊娠中期、妊娠末期、泌乳早期和泌乳中后期6个乳腺发育时期,采用酶联免疫吸附法测定血液中雌激素、孕酮、催乳素、生长激素、糖皮质激素,胰岛素和胰岛素样生长因子I的浓度,分析激素对绵羊乳腺发育的调控作用.[结果]雌激素和孕酮浓度呈先上升后下降的总体趋势,它们在妊娠末期的浓度最高(分别为73.01 pg/mL和530.48 pmol/L),在空怀期的浓度最低(分别为35.69 pg/mL和485.46 pmol/L);从空怀期开始,催乳素浓度持续升高,在泌乳早期达到最大值,其在泌乳早期的浓度分别比妊娠中期、泌乳中后期、妊娠早期和空怀期高12.47％、16.17％、46.15％和59.66％(P＜0.05);妊娠末期的糖皮质激素浓度最大(495.28 pg/mL),较妊娠早期和空怀期分别高14.36％和12.42％(P＜0.05);胰岛素含量由大到小依次为妊娠早期(36.22 mIU/L)＞妊娠末期(36.10 mIU/L)＞泌乳早期(35.98 mIU/L)＞妊娠中期(35.49 mIU/L)＞空怀期(33.78 mIU/L)＞泌乳中后期(32.22 mIU/L),空怀期、泌乳中后期与其它时期的胰岛素含量差异显著(P＜0.05).然而,生长激素和胰岛素样生长因子I的浓度在6个时期之间无显著差异(P＞0.05).[结论]在绵羊6个乳腺发育时期,雌激素、孕酮、催乳素、糖皮质激素和胰岛素这5种激素的浓度有显著差异(P＜0.05),说明它们可能影响了绵羊乳腺的生长发育和泌乳功能.

microRNAs (miRNAs) are involved in the regulation of biological phenomena by down-regulating the expression of mRNAs. In this study, Liaoning cashmere (LC) goats (n = 6) and Ziwuling black (ZB) goats (n = 6) with different cashmere fiber production performances were selected. We supposed that miRNAs are responsible for the cashmere fiber trait differences. To test the hypothesis, the expression profiles of miRNAs from the skin tissue of the two caprine breeds were compared using small RNA sequencing (RNA-seq). A total of 1293 miRNAs were expressed in the caprine skin samples, including 399 known caprine miRNAs, 691 known species-conserved miRNAs, and 203 novel miRNAs. Compared with ZB goats, 112 up-regulated miRNAs, and 32 down-regulated miRNAs were found in LC goats. The target genes of the differentially expressed miRNAs were remarkably concentrated on some terms and pathways associated with cashmere fiber performance, including binding, cell, cellular protein modification process, and Wnt, Notch, and MAPK signaling pathways. The miRNA-mRNA interaction network found that 14 miRNAs selected may contribute to cashmere fiber traits regulation by targeting functional genes associated with hair follicle activities. The results have reinforced others leading to a solid foundation for further investigation of the influences of individual miRNAs on cashmere fiber traits in cashmere goats.