Differential gene expression of Eph‐ephrin A1 and LEPR‐LEP with high or low number of embryos in pigs during implantation

The objective of this study was to ascertain whether mRNA and protein expressions of implantation‐related genes (erythropoietin‐producing hepatocellular receptor–ligand A1, Eph‐ephrin A1 and leptin receptor–leptin, LEPR‐LEP) differed between pigs with high and low number of embryos, and whether these differences in gene expression might affect embryo implantation. Experimental pig groups (n = 24) for high and low number of embryos were prepared by altering the number of eggs ovulated in pre‐pubertal gilts treated with 1.5 × (High) or 1.0 × (Low) PG600 ([400 IU PMSG + 200 IU hCG]/dose, AKZO‐NOBEL). Gilts expressing oestrus were artificially inseminated twice and maintained in breeding and gestation until the reproductive tract was collected on day 22 of pregnancy. At slaughter, the reproductive tracts from each pregnant gilt from each treatment were immediately processed to collect samples for RNA and protein analysis. Within each gilt, three conceptus points were sampled, one from each horn and then a random conceptus within the tract. At each conceptus point, endometrial attachment site, chorion–allantois and embryo were collected and immediately frozen in liquid nitrogen. Number of corpus luteum (CL) (35.4 vs. 12.6) and total embryo number (18.8 vs. 10.2) were greater in the high‐embryo compared to the low‐embryo group, respectively (p < .05). Real‐time qPCR results showed that Eph‐ephrin A1 mRNA expression was less in the high‐embryo (p < .05) compared to the low‐embryo group. In addition, Western blotting analysis indicated that Eph‐ephrin A1 and LEP protein expression at endometrial attachment site in high‐embryo was less (p < .05) compared to low‐embryo group. It was also noted that mRNA expression of Eph‐ephrin A1 and LEPR‐LEP was greater in pregnant than non‐pregnant gilts (p < .05). Moreover, mRNA expression of Eph‐ephrin A1 (p < .05) and LEPR‐LEP was greatest at endometrial attachment site among all three tissues. There was a positive correlation between expressions of Eph‐ephrin A1, LEPR‐LEP and embryo length with the correlation coefficient 0.31–0.59. For Eph‐ephrin A1, the highest correlation coefficient appeared between Eph A1 expression and normal embryo number, between ephrin A1 expression and embryo length. For LEPR‐LEP, the highest correlation coefficient appeared between LEPR‐LEP expression and ovary weight (0.79 for both, p < .05), followed by embryo length and weight. The results of this study suggest that low expression of Eph‐ephrin A1 and LEPR‐LEP is somehow related to increased embryo number during implantation and that endometrial attachment site might be the main target tissue of these gene products. Yet, the increased expression of Eph‐ephrin A1 and LEPR‐LEP appeared associated with increased embryo growth (length and weight) and ovary weight, Eph‐ephrin A1 and LEPR‐LEP might play roles in the regulation of embryo implantation in pigs.     

梁子湖和淤泥湖团头鲂体脂沉积差异比较

为探讨长江中下游地区梁子湖和淤泥湖团头鲂脂肪沉积和生长发育规律,采用HE染色观察2个种质资源区团头鲂脂肪和肝脏组织的形态学及脂肪沉积变化,并用qPCR技术检测脂肪和肌肉组织中LEP、LPL、IGF-1和NPY基因表达,初步分析来自2个种质资源区团头鲂在生长和脂肪沉积能力上存在的差异。结果显示,淤泥湖团头鲂的肠系膜脂肪含量是梁子湖的约1.5倍,HE染色发现,梁子湖团头鲂脂肪和肝脏细胞的脂滴直径比淤泥湖的小;但梁子湖团头鲂肌肉及脂肪组织中的LEP mRNA表达量显著高于淤泥湖的,肌肉组织中IGF-1mRNA的表达量也显著高于淤泥湖的,梁子湖团头鲂脂肪组织LPL mRNA表达量和淤泥湖的相比,无显著差异,2个种质资源区团头鲂NPY的mRNA表达在肌肉和脂肪组织中也没有显著性差异。由此推测,组织中体脂沉积能力及相关基因表达存在差异可能是导致梁子湖和淤泥湖团头鲂生长速度不同的主要原因之一。     

Productive performance of the dairy cattle Girolando breed mediated by the fat-related genes DGAT1 and LEP and their polymorphisms

Candidate genes have been associated with milk production in bovines, such as the diacylglycerol O-acyltransferase 1 (DGAT1) and leptin (LEP); however, they have not been simultaneously investigated nor have been evaluated in the Brazilian Girolando breed (Gir × Holstein, backcrossed to Holstein). Our aim was to determine the influence of fat-related genes, DGAT1 and LEP, and their polymorphisms on performance traits of milk production in the Girolando breed. Results indicated that the K allele of the DGAT1 gene showed a significant association with total and average daily milk production with additive effect. The LEP gene showed that the A allele and its homozygote are highly prevalent and almost fixed in this population and may have been favorably selected during backcrossing for the origin of this breed. The important impact of the K allele of the DGAT1 gene on milk production corroborates the initiative of performing marker-assisted selections with this gene in breeding programs of the Girolando breed.     

狂犬病病毒中和抗体测定方法研究

在Ｋａｚｕａｋｚ报道的微量免疫酶技术（ＭＩＥＴ）的基础上，以健康细胞对照孔ＯＤ值均数加３倍标准差作为间接ＥＬＩＳＡ判定标准，进而建立了求中和剂量的新方法。通过用中和９９％病毒的一致判定标准同经典的小鼠中和试验（ＭＮＴ）比较看，试验所建立的方法可代替ＭＮＴ。     

饲粮蛋白质水平对云南半细毛羊空怀母羊体增重、血清尿素氮、瘦素及繁殖激素的影响

为研究不同饲粮蛋白质水平对云南半细毛羊空怀母羊生长速度、血清尿素氮(BUN)、瘦素(LEP)和繁殖激素的影响,试验选用50只空怀期云南半细毛羊,平均分为5组,分别饲喂蛋白质水平为8.44%、9.95%、12.31%、13.58%、15.90%的饲粮,试验期为44d,14d预试期和30d正式试验。结果表明:(1)各组初始体重、末重和料重比均差异不显著(P>0.05);组3的日增重较组2显著降低31.00%(P<0.05)、平均日采食量较组2显著降低8.72%(P<0.05),其余各组的日增重和平均日采食量差异不显著(P>0.05);组2的日均蛋白质采食量较组1提高24.04%(P<0.01)、组3较组2提高13.10%(P<0.05)、组4较组3提高14.45%(P<0.01)、组5较组4提高14.85%(P<0.01)。(2)BUN浓度随饲粮蛋白质水平的升高而显著增加(P<0.05),除第3组和第4组外,其余各组间差异达到极显著水平(P<0.01),且从组2到组5依次较前一组提高34.65%(P<0.01)、34.94%(P<0.01)、7.29%(P<0.05)、10.12%(P<0.01)。(3)组5的LEP浓度较组2显著降低29.23%(P<0.05),较组4降低36.11%(P<0.05),其余各组间差异不显著(P>0.05)。本研究中饲粮蛋白质水平为9.95%时表现出较好的采食量和较快的生长速度,而且料重比、BUN相对不高,因此在实际生产中推荐云南半细毛羊母羊空怀期的饲粮蛋白质水平为9.95%。     

甘肃地方肉牛群体瘦素基因(LEP)部分序列SNPs及其与胴体品质和肉质性状的相关性分析

本研究旨在寻找与肉牛胴体肉质等主要经济性状相关的分子标记,为甘肃地方肉牛新类群的选育提供分子遗传学理论依据。利用PCR-SSCP技术检测甘肃地方肉牛LEP基因第2外显子及第3内含子部分序列多态性,并分析其多态性与胴体品质和肉质性状的相关性。结果表明：LEP基因第2外显子存在AA和AB两种基因型,基因型频率分别为0.5217和0.4783;测序结果显示：在该基因1180 bp处存在一个C→T碱基突变,导致所编码的氨基酸由精氨酸变为半胱氨酸;该群体的多态信息含量处于0.25~0.5之间,属于中度多态（PIC〉0.25）;胴体和肉质性状相关性统计分析表明：该位点AA基因型与宰前活重、胴体重、净肉重、屠宰率和净肉率显著相关（P〈0.05）,AB基因型与失水率、板油重、大理石花纹等级和肉色等级显著相关（P〈0.05）,该位点SNP与胴体背膘厚、眼肌面积、蒸煮损失、剪切力、pH值差异不显著（P〉0.05）。初步判断该位点可作为影响胴体品质和肉质性状的遗传标记位点之一。     

瘦素基因的研究进展

瘦素（leptin,LEP）是白色脂肪分泌的一种蛋白质激素,在哺乳动物中,LEP是一种16-ku的肽类激素,在能量平衡的神经内分泌和外周调节中发挥重要作用,是反应体脂含量和调节体重、摄食的重要信号因子。在人类疾病方面,LEP基因的表达对很多疾病的发生起着重要的调控作用,尤其是LEP基因的突变可能导致肥胖、糖尿病和乳腺癌等疾病;在畜牧生产上,LEP基因的表达对牛、羊和猪的采食和生长性状影响显著。为了加深对LEP基因的认识,作者对LEP基因的结构及LEP的分布、结构和功能进行了总结,并对近几年LEP基因在疾病和畜牧生产方面的研究进展进行了综述。     

测定狂犬病病毒中和抗体的微量免疫酶试验

在Kazuakz等报道的微量免疫酶技术(MIET)的基础上,以健康细胞对照孔OD值均数加3倍标准差作为间接ELISA判定标准,进而建立了求中和剂量的新方法.通过用中和99%病毒的一致判定标准同经典的小鼠中和试验(MNT)比较看,本试验所建立的方法可代替MNT.