瘦素的研究进展(综述)

瘦素(Leptin)是新近发现的一种蛋白质激素,主要由脂肪细胞分泌。它对动物摄食、能量代谢、脂肪存储、生殖活动等有调控作用。瘦素基因和瘦素受体基因的突变,可导致动物机体过度肥胖和不育症等。用瘦素可治疗动物的肥胖症和不育症,但对一些动物个体无效,表明存在瘦素抵抗。     

瘦素调节动物体重的研究进展

瘦素是调节动物体重的重要物质,文章重点阐述了瘦素与其他神经肽的相互作用,瘦素对动物短期采食行为的影响,并就瘦素调节体重过程中所产生的颉颃现象作了分析,最后就瘦素在动物生产上的应用前景及其研究方向作了一些展望和建议。     

鱼类瘦素受体研究进展

瘦素受体是一种跨膜受体,属于Ⅰ类细胞因子受体家族成员,广泛分布于动物机体的中枢及外周组织,在瘦素发挥生理调节功能的过程中起决定性作用.文章对鱼类瘦素受体的亚型分类、结构特点、信号通路、组织表达分布及其表达影响因素等研究现状进行综述,发现有关水温、pH和盐度等水体环境因子对鱼类瘦素受体表达水平影响的系统研究相对缺乏,因此今后应重点对比研究鱼类与哺乳动物间的瘦素受体生理学,揭示二者在结构特点和生理功能等方面的差异,并从进化角度探讨瘦素受体及其配体在演化过程中所扮演的角色;分析不同水体环境及鱼类各生长发育阶段中瘦素受体的基因表达调控模式,为水产养殖条件优化与品种选育等提供理论依据.     

Leptin与动物繁殖

Leptin(瘦素)是一种主要由脂肪组织分泌的肽类激素,除调节动物的机体代谢和能量平衡外,在动物的生殖器官发育,性激素分泌和妊娠等方面也发挥了重要的作用。本文综述了最近有关leptin的研究进展。     

绵羊血浆瘦素的影响因素

瘦素是主要由脂肪组织分泌的一种蛋白质，其分泌受到很多因素的影响。绵羊血浆瘦素水平取决于其能量摄取和脂肪储存，同时受到体内多种因素的影响。本文综述营养因素、生理因素和环境因素对绵羊血浆瘦素的影响。资料表明：血浆瘦素浓度与体脂水平呈正相关，且体脂是其他因素对血浆瘦素产生影响的基础。葡萄糖和胰岛素在血浆瘦素的短期调节中起到重要作用。此外，绵羊的妊娠一泌乳周期本身也能调节血浆瘦素水平。这些有助于理解绵羊血浆瘦素的体内调节特点以及阐述绵羊血浆瘦素的调节机理。     

瘦素的生物学功能及其对脂肪代谢调控的研究进展

瘦素（Leptin）是由肥胖基因（Obese gene）编码、脂肪组织合成并分泌的一种激素，具有调节动物摄食行为、减少能量消耗和降低动物采食量的作用，从而提高动物生产的经济效益。文章阐述了Leptin的结构特点、作用机理、能量代谢调控，并对Leptin在畜牧业中的应用前景进行了展望。     

Leptin的作用机理及其在动物生产上的应用

瘦素是由肥胖基因(Obese gene)编码,脂肪细胞分泌的一种激素样蛋白质,具有调节摄食行为﹑减少能量消耗和降低采食量的作用,并可通过下丘脑或直接作用于卵巢,对动物青春期的发育、生殖器官的发育以及性激素的分泌起重要的调节作用。本文对瘦素的生物学特性﹑作用机理及其生物学功能等进行了阐述,并展望了其在畜牧生产中的应用前景。     

瘦素对动物乳腺调控的研究进展

瘦素是主要由脂肪细胞分泌的一种激素样蛋白质。文章主要对乳腺的发育、泌乳和退化各个时期乳腺自身产生的瘦素及其长型受体的蛋白表达定位,乳腺不同发育阶段瘦素及其受体的生物学功能,乳腺中瘦素的作用机理的研究进展作以综述。     

瘦素与乳腺发育和泌乳

瘦素是一个可由乳腺脂肪垫和腺泡上皮细胞产生的自分泌和旁分泌因子。近年来,越来越多的研究发现它对乳腺的发育、泌乳和退化都有一定的影响。文章就瘦素在乳腺中的研究进展作一综述。     

国家自然基金项目《乳腺发育和泌乳过程中瘦素及其受体的表达与作用》通过验收

<正>由李庆章教授主持的国家自然基金项目《乳腺发育和泌乳过程中瘦素及其受体的表达与作用》通过验收。瘦素是影响乳腺发育和泌乳的自分泌和旁分泌因子,为乳腺生长发育和功能所必需。为探讨瘦素在乳腺发     

新疆褐牛瘦素基因在不同部位中表达水平与肉质指标的关联性

[目的]肉品质与物种的遗传因素具有一定的关联性.新疆褐牛瘦素基因在不同部位中表达水平与肉质指标的关联性,为牛肉属性差异的品质标识提供参考.[方法]选取新疆褐牛为研究对象,采用荧光定量聚合酶链式反应(qRT-PCR)技术测定新疆褐牛皮下、肌间、肾周、心周4个部位脂肪组织中的瘦素基因(lep-tin)的表达水平,检测活重、...     

DGAT基因在畜禽育种中的应用

DGAT是一种甘油酰基转移酶(Diacylgycerol Acyltransferase,DGAT),该酶与脂肪代谢、脂类在组织中的沉积有很大关系,它的主要作用机制是使二酰甘油加上脂肪酸酰基形成三酰甘油。编码该酶的基因有DGAT1和DGAT2,前者属于ACAT基因家族,后者属于DGAT2基因超家族。综述了DGAT基因定位、结构、生物学效应及在畜禽育种上的应用,并对DGAT基因在畜禽育种中的应用前景进行了探讨。     

立式液压毛皮去脂机的研制

去脂是动物毛皮加工的第二道工序，是在动物扒皮之后去掉鲜皮上的脂肪。本文介绍了实现去脂机械化的立式液压毛皮去脂机的结构和工作特点     

The Study on Correlation Analysis of Single Nucleotide Polymorphism of IGF2 Gene and Body Fatness Traits in Chicken

Insulin-like growth factor Ⅱ has profound effects on the growth and differentiation of animal embryo. Some researches indicated that it affects the fat metabolism of poultry.This study was designed to investigate the effect of IGF2 on chicken fatness traits.Broiler, Hyline Brown layer and three native breeds (Shiqiza, Beijing You, Baier) were used in this research. Body weight and body composition traits were measured in broiler line at the age of 7 weeks. Primers for exon2 in IGF2 were designed from database of chicken genomic sequence. Polymorphisms were detected by PCR-SSCP and DNA sequencing.The total χ2 test results showed that there was a significant difference (P＜ 0.01) in the frequency of genotype among breeds. A C/G mutation at base position 139 was found among individuals in broiler line and the least square analysis showed that BB genotype birds had significant lower (P＜ 0.05) abdominal fat weight and percentage of abdominal fat than AA or AB genotype birds. From the results we can conclude putatively that IGF2 gene is the major gene affecting the fatness traits of chicken or it links with the major gene,and the mutation could be used as the molecular genetic marker to select the chicken for low abdominal fat.     

Genetic Parameters for Milk,Fat Yield and Age at First Calving of Chinese Holsteins in Heilongjiang

Genetic parameters for milk,fat yield and age at first calving of Chinese Holsteins in Heilongjiang were evaluated using multiple-trait restricted maximum likelihood procedures with an animal model.Data consisted of records of 2496 Chinese Holsteins first lactation cows collected from 1989 to 2000.The model included 21 herd effects,four calving season effects,nine age at first calving effects,6697 animal effects.(Co) variance components of milk yield,fat yield and age at first calving were estimated with software package for variance component estimation(VCE) by an animal model.The heritabilities were 0.14,0.21,0.38 for milk yield.fat yield and age at first calving ,respectively,.The estimates of genetic correlation between milk yield and fat yield ,age at first calving were 0.96,-0.29,respectively,The estimate of genetic correlation between fat yield and age at first calving was -0.28.     

亮氨酸和异亮氨酸对脂肪沉积的影响及机制

亮氨酸具有调节糖脂代谢,降低肥胖动物脂肪沉积功能。饲喂高脂日粮建立肥胖动物模型,应用RT-PCR、免疫组化技术检测脂代谢基因Ampk,Atgl,Hsl,Acc,Fas,Sirt1及其相关基因SREBP1c和PPARγ表达水平,运用16S高通量测序检测肠道菌群变化情况。结果表明,添加亮氨酸、异亮氨酸和二者混合物均显著降低脂肪重量,增加Ampk等脂解基因表达水平,降低SREBP1c等脂合成基因表达水平,提高Lachnospiraceae丰度而降低Desulfovibrionaceae丰度。亮氨酸、异亮氨酸及其混合物可通过Sirt1的介导调控脂代谢基因表达,改善肠道菌群,降低脂肪沉积,对于治疗肥胖及改善畜产品品质具有重要意义。     

家兔中microRNA的研究进展

microRNA(miRNA)是一类内源性非编码单链RNA分子,通过与靶基因mRNA配对以指导其功能表达,在动物中扮演着重要的基因调节作用。研究表明,miRNA广泛参与调节动物的生长发育、生殖调控、新陈代谢和疾病发生等生命过程。本文综述了miRNA在家兔中的研究,例如促进肌肉细胞增殖分化、调节脂肪代谢和影响疾病发生等,探讨miRNA在家兔中的研究现状和发展方向,旨在为家兔遗传育种与繁殖提供理论依据。     

南方地区中国荷斯坦牛DGAT1基因多态性与泌乳性状的关联分析

 【目的】探索南方地区中国荷斯坦牛DGAT1基因多态性与泌乳性状的相关性。【方法】以上海光明乳业集团金山奶牛场30个公牛家系的605头中国荷斯坦牛为试验材料,采用PCR-SSCP法分析DGAT1基因K232A位点遗传多态性,采用混合动物模型分析DGAT1基因K232A位点突变对测定日产奶量、乳脂率、乳蛋白率、305 d校正产奶量、乳脂量、乳蛋白量及体细胞评分7个泌乳性状的影响。【结果】共检测到KK、KA和AA三种基因型,频率分别为0.7918、0.1917和0.0165,等位基因K和A的频率分别为0.8876和0.1124。该位点突变对测定日产奶量、乳脂率、乳蛋白率、305 d校正产奶量、乳蛋白量的影响达到极显著水平(P＜0.01),对乳脂量的影响达到显著水平(P＜0.05),对乳中体细胞评分影响不显著(P＞0.05)。多重比较表明,KK和KA型测定日产奶量、305 d校正产奶量和乳蛋白量极显著高于AA型(P＜0.01),AA型乳脂率和乳蛋白率极显著高于KK和KA型(P＜0.01)。【结论】DGAT1基因K232A位点突变对中国荷斯坦牛泌乳性状有较大的遗传效应,可用于其泌乳性状的分子标记辅助选择。     

Association of Leptin Gene (LEP) Polymorphism with Growth Rates and Milk Production in Holstein First-Calf Heifers

The objective of the work is to study the polymorphic leptin gene variants and their influence on growth, development, and milk production of Holstein first-calf heifers, whose 172 blood samples were analyzed. Genotyping the leptin gene locus was performed with the PCR-RFLP method. The frequencies of occurrence of the C and T alleles comprised 0.62 and 0.38, respectively; the values for genotypes CC, TC, and TT comprised 35.5% (61 animals), 53.3% (90 animals), and 12.2% (21 animals), respectively. It was ascertained that the analyzed animal population is in the genetic balanced equilibrium state according to the Hardy–Weinberg law. Under similar conditions of feeding and nutritional supplement, the animals having genotype CC were significantly superior to their peers with the other genotypes in all the parameters characterizing the live weight at different ages. However, the milk yield, the fat mass fraction, the milk fat yield, and the milk protein yield in the specimens having the TT genotype were higher by 8.9% (P ≤ 0.01; 673.4 kg), 0.20, 12.9% (P ≤ 0.05; 38.4 kg), and 9.0% (P ≤ 0.05; 22.7 KG), respectively, than that in the genotype TC carriers. The coefficient of milkability was 142.1 kg higher in all the first-calf heifers when compared to the lower value for the entire herd, therefore, indicating the specific dairy type of the analyzed animal population. The obtained data can prove the associations between the different genotypes of the leptin gene and the growth rates, the physical development, and the milk production in Holstein cattle.     

Brown fat: thermogenic effector of arousal in hibernators

Earlier indications that brown fat has a thermogenic role in rats exposed to cold suggested that certain comparable functions in hibernating marmots be investigated. From the results it appears that arousal of the animal by cold is induced by sympathetically activated thermogenesis in areas of brown fat so located, relative to the vasculature, that heat is transferred to the thoracic structures and cervical spinal regions.