绵羊WNT5A基因克隆及其组织表达分析

WNT5A(Wnt family member 5A)参与了多种细胞的增殖、凋亡和分化等生物学过程,在乳腺形态发生、毛囊发育等方面发挥了重要作用。该试验利用RT-PCR获得绵羊WNT5A基因的CDS区,分析WNT5A蛋白的结构特征并利用RT-qPCR检测WNT5A基因在9个组织中的表达情况。绵羊WNT5A基因的CDS区全长1062 bp,编码353个氨基酸。该蛋白的二级结构主要以α-螺旋和无规则卷曲为主,β转角、延伸链贯穿于整个蛋白质结构中。String分析结果表明,WNT5A与卷曲蛋白受体、低密度脂蛋白相关蛋白和受体酪氨酸激酶有相互作用。RT-qPCR研究结果表明,WNT5A基因表达具有组织特异性及品种特异性。WNT5A基因在绵羊心脏、肝脏、肺脏、脾脏、肾脏、卵巢、背最长肌、乳腺和皮肤9个组织中均广泛表达,其中在皮肤中的表达量高于其他组织(P<0.05),而在脾脏中表达量较低。它在甘肃高山细毛羊皮肤、乳腺、背最长肌、肾脏、肺脏、脾脏和肝脏中的表达量高于小尾寒羊(P<0.05),而在甘肃高山细毛羊卵巢中的表达量低于小尾寒羊(P<0.05),在心脏中该基因的表达量无差异(P>0.05)。该结果为深入研究绵羊WNT5A基因的功能提供了重要依据,同时也丰富了绵羊基因组内容。     

Mammary carcinoma arising in an adenoma in a ewe

A large, firm, multi-cystic mammary gland mass grew slowly over 4 y in a 12-y-old, female Finn–Shetland cross sheep. A diagnosis of epithelial malignancy was suspected following fine-needle aspiration cytology at 30 mo after initial observation. The sheep was euthanized when the flock was downsized 18 mo later. A field postmortem examination revealed a large mammary mass, but an absence of metastases to internal organs. Imprint cytology of the mammary tissue supported a benign proliferative process. Histologically, mammary tissue was obliterated by cystic, tubular, and papillary adenomatous arrangements of mammary epithelium, with an anaplastic component, consistent with mammary carcinoma arising in an adenoma. IHC showed strong nuclear positivity to the antibody against progesterone receptor and minimal positivity to the antibody against estrogen receptor alpha expression. Intrinsic subtyping for basal or luminal epithelial origin was attempted through adaptation of companion animal IHC classification panels; high- and low-molecular-weight cytokeratins (CK5, CK8, CK18) failed to stain, but p63 expression for basal epithelium was positive.     

引进肉用绵羊品种的杂交利用研究进展

文章综述了从国外引进优良肉用绵羊品种对国内不同地方绵羊品种杂交改良方面的研究应用情况,重点介绍了萨福克羊、杜泊羊、无角陶赛特羊、美利奴羊、特克塞尔羊等优良绵羊品种与我国不同地方绵羊品种杂交,其杂交后代在生长发育性能、产肉性能、胴体品质等方面的表现,旨在总结中国肉用绵羊的杂交改良工作,为推动中国肉用绵羊杂交改良,提高地方绵羊的生长性能和肉用性能,扩大我国肉羊的生产规模,促进我国畜牧业的健康发展和动物性肉食结构平衡提供借鉴。     

Identification of SNPs and expression patterns of FZD3 gene and its effect on wool traits in Chinese Merino sheep(Xinjiang Type)

As a member of the Frizzled family, Frizzled3(FZD3) is a receptor of the canonical Wnt signaling pathway and plays a vital role in mammalian hair follicle developmental processes. However, its effects on wool traits are not clear. The objectives of this study were to identify the single nucleotide polymorphisms(SNPs) and the expression patterns of FZD3 gene, and then to determine whether it affected wool traits of Chinese Merino sheep(Xinjiang Type) or not. PCR-single stranded conformational polymorphism(PCR-SSCP) and sequencing were used to identify mutation loci, and general linear model(GLM) with SAS 9.1 was used for the association analysis between wool traits and SNPs. Quantitative real-time PCR(q RTPCR) was used to investigate FZD3 gene expression levels. The results showed that six exons of FZD3 gene were amplified and two mutation loci were identified in exon 1(NC_019459.2: g.101771685 TC(SNP1)) and exon 3(NC_019459.2: g.101810848, AC(SNP2)), respectively. Association analysis showed that SNP1 was significantly associated with mean fiber diameter(MFD)(P=0.04) and live weight(LW)(P=0.0004), SNP2 was significantly associated with greasy fleece weight(GFW)(P=0.04). The expression level of FZD3 gene in skin tissues of the superfine wool(SF) group was significantly lower(P0.05) than that of the fine wool(F) group. Moreover, it had a higher expression level(P0.01) in skin tissues than in other tissues of Chinese Merino ewes. While, its expression level had a fluctuant expression in skin tissues at different developmental stages of embryos and born lambs, with the highest expression levels(P0.01) at the 65 th day of embryos. Our study revealed the genetic relationship between FZD3 variants and wool traits and two identified SNPs might serve as potential and valuable genetic markers for sheep breeding and lay a molecular genetic foundation for sheep markerassisted selection(MAS).     

Comparison of the microbial communities of alpacas and sheep fed diets with three different ratios of corn stalk to concentrate

The objective of this study was to investigate the characteristics of ruminal microbial communities of alpacas (Lama pacos) and sheep (Ovis aries) fed three diets with varying ratios of roughage (corn stalk) to concentrate, 3:7 (LS), 5:5 (MS) and 7:3 (HS). Six alpacas (one-year-old and weighing 29.5 ± 7.1 kg) and six sheep (one-year-old and weighing 27.9 ± 2.7 kg) were used in this study, in a replicated 3 × 3 Latin square experiment. Total protozoa concentration was determined under the microscope; total fungi and methanogens were assessed using quantitative polymerase chain reaction and expressed as a percentage of total bacterial 16S rRNA gene copies; bacterial communities were investigated by targeted 16S rRNA gene (V3–V4 region) sequencing. The percentage of fungi was significantly higher in alpacas than in sheep under the LS diet, while the concentration of protozoa was significantly lower in alpacas under HS, MS and LS diets. The alpha diversity including Shannon, Chao l and ACE indices of bacterial communities was higher in alpacas than in sheep, under the LS diet. A total of 299 genera belonging to 22 phyla were observed in the forestomach of alpaca and sheep, with Bacteroidetes and Firmicutes dominating both animal species. Phyla Armatimonadetes and Fusobacteria, as well as 64 genera, were detected only in alpacas, whereas phyla Acidobacteria and Nitrospira, as well as 44 genera, were found only in sheep. The abundance of cellulolytic bacteria, including Butyrivibrio and Pseudobutyrivibrio, was higher in alpacas than in sheep under all three diets. These differences in the forestomach microbial communities partly explained why alpacas displayed a higher poor-quality roughage digestibility, and a lower methane production. Results also revealed that the adverse effects of high-concentrate diets (70%) were lesser in alpacas than in sheep.     

Expression and functional analysis of the Follistatin-like 3 (FSTL3) gene in the sheep ovary during the oestrous cycle

Follistatin-like 3 (FSTL3) is a regulator of cellular apoptosis and was previously identified via RNA-Seq to be associated with follicular development in mammalian ovaries. However, the mechanism underlying the FSTL3 regulation of oestrus in sheep remained poorly understood. In this study, the oestrogen (E2) and progesterone (P4) concentrations in blood were detected, and the expression level and functional analysis of FSTL3 in the ovary were studied during the different reproductive stage in Aohan fine wool sheep (seasonal breeding breed in China). The concentrations of E2 and P4 at the anestrus were significantly lower compared to dioestrus, proestrus and oestrus stages. Higher expression levels of FSTL3 were observed in the sheep ovary, hypothalamus, and thyroid. During different reproductive stages, higher expression levels were found during the stages of dioestrus and proestrus, while lower levels were found during the oestrus and anestrus stages. Functional analysis of FSTL3 was performed in primary granulosa cells (GCs) of sheep. The concentration of E2 increased significantly after RNAi interference of FSTL3, while the P4 level decreased. FSTL3 can decrease P4 levels, which might be involved in mediating oestrous cycle in sheep.     

盐酸多西环素片在羔羊体内残留消除规律及休药期分析

旨在确定盐酸多西环素片按照给药说明给药后在羔羊体内的残留消除规律及休药期。将盐酸多西环素片根据体重以5 mg·kg^-1内服给药，间隔24 h，连续给药5次。在最后1次给药后，分别在第0（12小时）、1、2、3、5、7和9天时间点采集羔羊脂肪、肌肉、肝和肾，采用建立并验证的HPLC-VWD方法测定组织中多西环素的含量。结果显示：方法学考察结果表明，在50~5 000 ng·mL^-1添加的线性方程和相关系数为y=0.044x-0.414，R²=0.999。试验结果表明，多西环素在羔羊组织中代谢快速，最后1次给药后第9天，在肌肉、肝、肾和脂肪中均未检测到多西环素。本试验以5 mg·kg^-1体重内服给予羔羊盐酸多西环素片后，根据欧洲药品评估机构法规《EMEA/CVMP/036/95》，建议盐酸多西环素片在羔羊组织中的休药期为2 d。     

绵羊羊角形态与遗传调控机制的研究进展

绵羊是较早驯化的家畜之一，可为人类提供肉、毛、奶等产品，因而在我国畜牧产业中占有重要的地位。由于各地自然环境的差异和社会需要的不同，经长期的选择形成了数百个外表特征和生理习性各具特色的绵羊品种。羊角作为绵羊品种的特征性表型，承担着双重功能，发达的羊角不仅有利于公羊个体提高其在种群内的地位，拥有优先交配权，还可以有效抵御天敌的攻击，使群体免受捕食伤害；然而，随着规模化养殖的推广，羊角的存在已不利于舍内饲养管理，进而对绵羊品种的培育工作提出了新要求。目前，羊角虽在实际生产和品种培育工作中受到广泛关注，但其形态多样性及遗传调控机制的研究尚显不足。本文根据我国现有绵羊品种，对角的数量和形态、发育过程、遗传调控机制等方面的研究进行了综述，不仅能为后期鉴别绵羊羊角多样性的突变位点和主效基因提供参考，也可为绵羊的新品种培育奠定相关的理论基础。     

全混合颗粒料中添加不同类型蛋氨酸对湖羊生长性能及血清生化指标的影响

本试验旨在研究在湖羊全混合颗粒料中添加不同类型蛋氨酸(蛋氨酸钙盐与蛋氨酸羟基类似物异丙酯)对湖羊生长性能及血清生化指标、抗氧化指标和激素含量的影响。选取体重为(19.99±2.04) kg的健康湖羊72只,随机分为3组:对照组、试验Ⅰ组(在基础饲粮中添加1.5 kg/t蛋氨酸钙盐)和试验Ⅱ组(在基础饲粮中添加1.5 kg/t蛋氨酸羟基类似物异丙酯),每组6个重复,每个重复4只(公母各占1/2)。预试期7 d,正试期80 d。结果表明:1)与对照组相比,试验Ⅰ组、试验Ⅱ组总增重、平均日增重均有上升的趋势,其中试验Ⅰ组总增重提高了12.8%(P>0.05),试验Ⅱ组总增重提高了3.1%(P>0.05);料重比方面,试验Ⅰ组、试验Ⅱ组均有下降的趋势,其中试验Ⅰ组下降了12.2%(P>0.05),试验Ⅱ组下降了3.6%(P>0.05)。2)试验Ⅱ组血清甘油三酯(TG)、总胆固醇(TCH)、低密度脂蛋白胆固醇(LDL-C)、总蛋白(TP)含量显著高于对照组和试验Ⅰ组(P <0.05)。3)血清抗氧化指标及激素含量各组之间无显著差异(P>0.05)。综上所述,全混合颗粒料中添加蛋氨酸羟基类似物异丙酯及蛋氨酸钙盐具有提高肉羊生长速度、降低料重比的趋势,同时影响部分血清生化指标,但对血清抗氧化指标及激素含量无显著影响。     

不同繁殖状态下绵羊繁殖相关组织中CHGA基因的表达分析

为探究绵羊繁殖相关组织中CHGA基因在不同繁殖状态下的表达差异，选取不同光照条件下的成年苏尼特母羊（季节性发情品种）及不同繁殖时期的小尾寒羊母羊（常年发情品种）的下丘脑等10种组织，利用qPCR技术分析不同繁殖状态下各组织中CHGA基因的相对表达量。结果表明，CHGA基因在2个绵羊品种的不同组织中广泛表达且脑部组织中该基因的表达量高于其他组织；不同光照条件下苏尼特羊各组织中CHGA表达差异均不显著（P＞0.05）；黄体期小尾寒羊垂体中CHGA表达量显著高于卵泡期（P＜0.05），子宫体中该基因的表达量极显著高于卵泡期（P＜0.01）。以上结果暗示CHGA基因可能参与小尾寒羊不同繁殖时期垂体和子宫生理变化的调控。