农林科学最新文献

The inducing activation event of secondary hair follicle (SHF)-stem cells is considered a key biological process in the SHF regeneration, and the morphogenesis of cashmere fiber in cashmere goats. The miR-361-5p was essentially implicated in the induced activation of SHF-stem cells of cashmere goats, but its functional mechanisms are unclear. Here, we confirmed miR-361-5p was significantly downregulated in anagen SHF bugle of cashmere goats compared with that at telogen, and miR-361-5p expression was significantly lower in SHF-stem cells after activation than its counterpart before activation. Further, we found that miR-361-5p could negatively regulate the induced activation event of SHF-stem cells in cashmere goats. Mechanistically, through dual-luciferase reporter assays, miR-361-5p specifically bound with FOXM1 mRNA in SHF-stem cells of cashmere goats and negatively regulated the expression of FOXM1 gene. Also, through overexpression/knockdown analysis of FOXM1 gene, our results indicated that FOXM1 upregulated the expression of Wnt/β-catenin pathway related genes in SHF-stem cells. Moreover, based on TOP/FOP-flash Wnt report assays, the knockdown of miR-361-5p promotes the Wnt/β-catenin pathway activation through upregulating the FOXM1 expression in SHF-stem cells. Finally, we demonstrated that miR-361-5p negatively regulated the induced activation of SHF-stem cells through FOXM1 mediated Wnt/β-catenin pathway in cashmere goats.

Cattle are sensitive to temperature fluctuations but adapt well to inclement weather conditions. When environmental temperatures exceed specific thresholds, heat stress becomes a critical concern for cattle. The TRPM2 gene, which resides on cattle chromosome 1 encodes a TRP channel protein, holding a unique capacity to sense temperature changes and facilitate rapid response to avoid heat stress. Here, we utilized the Bovine Genome Variation Database (BGVD) (http://animal.omics.pro/code/index.php/BosVar), and identified a missense mutation site, c.805A > G: p. Met269Val (rs527146862), within the TRPM2 gene. To elucidate the functional assessment of this mutation in temperature adaptation attributes of Chinese cattle, we genotyped 407 samples from 20 distinct breeds representing diverse climatic zones across China. The association analysis incorporates three temperature parameters and revealed compelling insights in terms of allele frequency. Interestingly, the prevalence of the wild-type allele A was notably higher among northern cattle breeds and this trend diminished gradually as observed in southern cattle populations. Conversely, the mutant-type allele G demonstrated a contrasting trend. Moreover, southern cattle exhibited markedly higher frequencies of GG and GA genotypes (P < 0.01). The presence of heterozygous and homozygous mutations appears to confer an enhanced capacity for adaptation to elevated temperatures. These results provide unequivocal correlation evidence between TRPM2 genotypes (AA, GA, GG) and environmental temperature parameters and comprehend the genetic mechanisms governing temperature adaptation in cattle. This provides valuable insights for strategic breed selection across diverse climatic regions, thereby aiding livestock production amid evolving climate challenges.

In this study, we investigated the effects of supplemental Glycyrrhiza polysaccharide (GCP) on growth performance and intestinal health of weaned piglets. Ninety piglets weaned at 28 days of age were randomly allocated to three groups with five replicates per treatment. Piglets were fed the following diets for 28 days: (1) CON (control group), basal diet; (2) G500, CON + 500 mg/kg GCP; (3) G1000, CON + 1000 mg/kg GCP. The results showed that supplementation with 1000 mg/kg GCP increased the average daily gain (ADG) and decreased the feed-to-gain ratio (F/G) (P < 0.05). Serum diamine oxidase (DAO) and D-lactic acid (DL-A) levels were lower in the G1000 group (P < 0.05). Dietary GCP 1000 mg/kg improved mucosal trypsin activity in the duodenum, jejunum and ileum and increased lipase and amylase activity in the jejunum (P < 0.05). Moreover, in the G1000 group, ZO-1, claudin 1 and occludin levels were increased in the jejunum mucosa, whereas interleukin-1β (IL-1β) and IL-6 levels were decreased (P < 0.05). The 16S rRNA gene analysis indicated that dietary 1000 mg/kg GCP altered the jejunal microbial community, with increased relative abundances of beneficial bacteria. In conclusion, dietary GCP 1000 mg/kg can improve growth performance, digestive enzyme activity, intestinal immunity, barrier function and microbial community in weaned piglets.

The thyroid gland is an important endocrine gland in animals, which mainly secretes thyroid hormones and acts on various organs of the body. Long-chain non-coding RNA (lncRNA) plays an important role in animal reproduction. However, there is still a lack of understanding of their expression patterns and potential roles in the thyroid of Small Tail Han (STH) sheep. In this study, RNA-seq was used to examine the transcriptome expression patterns of lncRNAs and mRNAs in the follicular phase (ww_FT) and luteal phase (ww_LT) in FecB⁺⁺ genotype STH Sheep. A total of 17,217 lncRNAs and 39,112 mRNAs were identified including 96 differentially expressed lncRNAs (DELs) and 1054 differentially expressed mRNAs (DEGs). Functional analysis of genes with significant differences in expression level showed that these genes could be enriched in Ras signalling pathway, hedgehog (HH) signalling pathway, ATP-binding cassette (ABC) transporters and other signalling pathways related to animal reproduction. In addition, through correlation analysis for lncRNA-mRNA co-expression and network construction, we found that LNC_009115 and LNC_005796 trans target NIK-related kinase (NRK) and poly(A)-specific ribonuclease (PARN). LNC_007189 and LNC_002045 trans target progesterone-induced blocking factor 1 (PIBF1), LNC_009013 trans targets small mothers against decapentaplegic (SMAD1) are related to animal reproduction. These genes add new resources for elucidating the regulatory mechanisms of reproduction in sheep with different reproductive cycles of the FecB⁺⁺ genotype STH sheep.

Mastitis in cows is caused by the inflammation of the mammary glands due to an infection by external pathogenic bacteria. Mammary gland epithelial cells, which are in direct contact with the external environment, are responsible for the first line of defense of the mammary gland against pathogenic bacteria, playing an essential role in immune defense. To investigate the mechanism of bovine mammary epithelial cells in the inflammatory process, we treated the cells with LPS for 12 hours and analyzed the changes in mRNA by transcriptome sequencing. The results showed that compared to the control group, the LPS treatment group had 121 up-regulated genes and 18 down-regulated genes. GO and KEGG enrichment analysis revealed that these differential genes were mainly enriched in the IL-17 signaling pathway, Legionellosis, Cytokine-cytokine receptor interaction, NF-kappa B signaling pathway, and other signaling pathways. Furthermore, the expression of GRO1 and CXCL3 mRNAs increased significantly after LPS treatment. These findings provide new insights for the treatment of mastitis in cows in the future.

Litter size in sheep is a complex trait controlled by micro-effective polygenes. APAF1, CLSTN2, CTH, PLCB1, PLCB4, and CHST11 are all involved in mammalian reproduction. However, the effects of these genes on litter size in sheep are still unclear. Therefore, in this study, we used Sequenom MassARRAY® SNP assay technology to type the single nucleotide polymorphisms (SNPs) loci of six genes in five sheep breeds. The results showed that most sheep breeds contain three genotypes at each locus. Then, we conducted population genetic analysis on the SNPs of six genes and found that the polymorphic information content in all sheep breeds ranged from 0 to 0.37, and most sheep breeds were in Hardy-Weinberg equilibrium (p > 0.05). In addition, association analysis in Small Tail Han sheep indicated that the rs399534524 locus in CLSTN2 was highly associated with first parity litter size, and litter size in ewes with CT genotype was higher than that in ewes with CC genotype or TT genotype. Furthermore, the rs407142552 locus in CTH was highly associated with second parity litter size in Small Tail Han sheep, and litter size in ewes with CT genotype was higher than that in ewes with TT genotype. Finally, we predicted the CTH and CLSTN2 protein interaction network and found that HTR1E, NOM1, CCDC174 and ALPK3 interact with CLSTN2 and have been reported as candidate genes related to litter size in sheep. These results suggest that they may be useful genetic markers for increasing litter size in sheep.

Matrix metalloproteinase 9 (MMP9) plays a pivotal role in mammary ductal morphogenesis, angiogenesis and glandular tissue architecture remodeling. However, the molecular mechanism of MMP9 expression in mammary epithelial cells of dairy cows remains unclear. This study aimed to explore the underlying mechanism of MMP9 expression. In this study, to determine whether the PI3K/AKT/mTORC1/NF-κB signalling pathway participates in the regulation of MMP9 expression, we treated mammary epithelial cells with specific pharmacological inhibitors of PI3K (LY294002), mTORC1 (Rapamycin) or NF-κB (Celastrol), respectively. Western blotting results indicated that LY294002, Rapamycin and Celastrol markedly decreased MMP9 expression and P65 nuclear translocation. Furthermore, we found that NF-κB (P65) overexpression resulted in elevated expression of MMP9 protein and activation of MMP9 promoter. In addition, we observed that Celastrol markedly decreases P65-overexpression-induced MMP9 promoter activity. Moreover, the results of the promoter assay indicated that the core regulation sequence for MMP9 promoter activation may be located at -420 ∼ -80 bp downstream from the transcription start site. These observations indicated that the PI3K/AKT/mTORC1 signalling pathway is involved in MMP9 expression by regulating MMP9 promoter activity via NF-κB in the mammary epithelial cells of dairy cows.

This study aimed to evaluate the genetic diversity and structure within the Dengchuan cattle population and effectively protect and utilize their germplasm resources. Herein, the single-nucleotide polymorphisms (SNPs) of 100 Dengchuan cattle (46 bulls and 54 cows) were determined using the GGP Bovine 100K SNP Beadchip. The results showed that among the Dengchuan cattle, a total of 101,220 SNPs were detected, and there were 83,534 SNPs that passed quality control, of which 85.7% were polymorphic. The average genetic distance based on identity-by-state (IBS) within the conservation population of Dengchuan cattle was 0.26 ± 0.02. A total of 3,999 genome-length runs of homozygosity (ROHs) were detected in the Dengchuan cattle, with ROH lengths primarily concentrated in the range of 1-5 Mb, accounting for 87.02% of the total. The average inbreeding coefficient based on ROHs was 4.6%, within the conservation population of Dengchuan cattle, whereas it was 4.9% for bulls, and the Wright inbreeding coefficient (F_IS) value was 2.4%, demonstrating a low level of inbreeding within the Dengchuan cattle population. Based on neighbor-joining tree analysis, the Dengchuan cattle could be divided into 16 families. In summary, the conservation population of Dengchuan cattle displays relatively abundant diversity and a moderate genetic relationship. Inbreeding was observed among a few individuals, but the overall inbreeding level of the population remained low. It is important to maintain this low level of inbreeding when introducing purebred bloodlines to expand the core group. This approach will ensure the long-term conservation of Dengchuan cattle germplasm resources and prevent loss of genetic diversity.

In goats, most follicles in the ovaries will be atresia and only a few dominant follicles (DFs) may eventually mature and ovulate at a follicular wave. To investigate the potential microRNAs (miRNAs) that regulate the expression of genes associated with follicular dominance or atresia, small RNA sequencing was performed on granulosa cells of DF and subordinate follicle at the first follicular wave in goats. A total of 108 differentially expressed miRNAs were detected in the two types of follicle granulosa cells: 16 upregulated miRNAs and 92 downregulated miRNAs. Kyoto Encyclopedia of Genes and Genomes analysis of the target genes showed that TKTL1, LOC102187810, LOC102184409 and ALDOA are closely associated with follicle dominance and are involved in the pentose phosphate pathway. Furthermore, a coexpression network of miRNAs and follicular dominance-related genes was constructed. The qPCR results well correlated with the small RNA sequencing data. Our findings provide new insight for exploring the molecular mechanism of miRNAs in regulating follicular development in goats.

Colostrum is the initial secretion of the mammary glands following parturition, which offers main food, protection, and biological active substances for the new born. The most threatening episode of neonate's life is the initial two weeks after birth. This period is associated with high neonatal mortality and morbidity. These worthwhile losses lead to a poor prolificacy rate, low profitability, and ultimately poor performance in animal production. Hence, both diseases and mortality cause valuable losses in terms of production and economic losses. The survival of neonate is correlated with their immune status and passive immune transfer (PIT). Colostrum provides the primary source of nutrition and immunity (PIT) that protects neonates against infections. It must be given as soon as possible after birth since its immunoglobulins are absorbed within the first 16-27 hours after birth, ideally within 2-4 hours. As a result, immunoglobulin (PIT) is the most important component of distressing infectious immunity, and a passable concentration of immunoglobulin in the blood of newborn lambs is linked to their health and survival rate. In this review, we summarized the importance of colostrum in early life and its association with neonatal lamb's survival, profitability and productivity of sheep farming.