重组瘦蛋白对猪蛋白质代谢的影响

利用重组瘦蛋白进行动物饲养试验研究。结果表明:重组瘦蛋白对猪蛋白质代谢指标有不同程度的影响。腹腔注射0.5 mg/kg和1.0 mg/kg体重重组瘦蛋白后,血清总蛋白(TP)和球蛋白(GPs)的含量高于对照组,其中0~3周差异显著(P<0.05),而血清白蛋白(ALB)的含量只在注射后第3周有明显提高;血清天门冬氨酸转氨酶(AST)有不同程度的提高,在注射后1~3周和5~7周内明显高于对照组(P<0.05);血清碱性磷酸酶(ALP)和丙氨酸转氨酶(ALT)只有在注射0.5 mg/kg体重重组瘦蛋白后0~3周明显提高(P<0.05);注射0.1 mg/kg体重重组瘦蛋白对猪蛋白质代谢指标无明显影响(P>0.05)。     

家兔体重与血清瘦素及肾功能关系研究

为探讨家兔的体重与血浆瘦素水平及肾功能的关系,将30只断奶,40日龄的健康雌性新西兰白兔按体重编号后,按随机数字表分为正常对照组(n=10),过饲组(n=10)及限饲组(n=10)3个组。分别通过不同的饲养方式,即对照组按兔子的营养标准正常饲喂,过饲组在正常对照组日饲喂量的基础上增加30%,限饲组则在正常对照组日饲喂量的基础上减少30%,饲养12周后,对各组的体重进行差异显著性检验,过饲组和限饲组的体重与对照组比较差异显著,具有统计学意义(P<0.05)。随后,分别测定血清瘦素(Lp)水平和肾功能指标尿素氮(BUN)、尿酸(UA)、肌酐(SCr)、总蛋白(TP)。结果表明,限饲组和过饲组的血清Lp水平均高于对照组,而且限饲组的血清Lp水平甚至高于过饲组(P<0.05);限饲组血清UA、SCr、BUN均高于对照组和过饲组(P<0.05),而过饲组与对照组相比无明显变化;限饲组血清TP低于对照组和过饲组(P<0.05),而过饲组与对照组相比无明显变化。由于动物限饲出现了营养不良、体重降低,会引发肾功能受损并伴随出现高瘦素血症情况;而肾功能受损和高水平的血清瘦素则加剧了机体的营养不良,从而导致体重的进一步下降。     

瘦素的生物学功能及其应用前景

瘦素可以降低脂肪含量、改变体组成、维持能量平衡，提高机体抗应激能力和免疫机能，促进动物新陈代谢。从而提高畜禽生产性能和经济效益。本文从调控机制、抗性、能量平衡及其在动物体内的作用等方面综述了瘦素生物学功能的研究进展，并从神经内分泌和分子生物学水平探讨瘦素的作用机理，指出其在畜牧业上的应用前景；     

牛瘦素受体基因表达及其结合瘦素特性研究

[目的]以秦川牛为研究对象,克隆、原核表达秦川牛瘦素受体(Lepr)基因的蛋白功能区,分析表达蛋白对瘦素结合特性,为研究瘦素受体与瘦素结合的调节机制提供理论基础.[方法]本研究通过RT-PCR法从秦川牛肉mRNA扩增获得Lepr IG基因的cDNA序列,克隆至pMD18-T载体获得重组质粒,并进行序列测定.将测序正确的...     

瘦素对动物初情期启动的调控

瘦素是一种主要由脂肪组织分泌的蛋白质激素，瘦素不仅调节体内的能量平衡，而且影响动物的生殖。它传递体内的营养状态和能量储存信号对中枢神经系统，在调控动物初情期启动的时间上占据一定的地位，但瘦素的作用机理目前还不清楚。     

瘦素及其受体对肌肉组织蛋白质代谢的调节

近年来,体内外试验研究表明,瘦素的短期或长期处理能够调节哺乳动物骨骼肌和肌细胞内蛋白质的代谢,而这主要是由于瘦素可以调节肌细胞内与蛋白质代谢相关的信号通路(如胰岛素相关信号通路和丝裂原活化蛋白激酶信号通路)的活性.因此,本文综述了瘦素及其受体在动物体内肌肉组织蛋白质代谢过程中的调节作用,并分析讨论了这一过程中瘦素的可能...     

Cry1Ac敏感和抗性小菜蛾bre-3和bre-5 基因mRNA的表达差异研究

在室内选用Cry1Ac对小菜蛾Plutella xylostella 3龄幼虫进行抗性选育,获得相对抗性为356倍的抗性种群DBM1Ac-R品系。应用实时定量基因扩增荧光检测(real time quantitative PCR,real-time qPCR)技术检测敏感小菜蛾DBM1Ac-S和抗性小菜蛾DBM1Ac-R品系鞘糖脂(Glycosphingolipids,GSLs)合成酶基因bre-3和bre-5 mRNA在2龄、3龄、4龄和老熟幼虫、蛹及4龄中肠的表达情况。结果显示:bre-3和bre-5在两个品系的5个时期和4龄中肠均有表达,其中DBM1Ac-S品系的bre-3 mRNA在3龄、4龄和老熟幼虫的相对表达量显著高于DBM1Ac-R品系(PPBacillus thuringiensis,Bt)杀虫晶体蛋白受体之一GSLs的进一步研究提供了一定的基础。     

The incidence of Dictyocaulus viviparous infections in cattle in the Netherlands

Summary

Examination of nearly 2000 sera indicated that approximately 90 per cent of cattle had acquired Dictyocaulus viviparus infections during the previous grazing season. No differences were found between provinces. Large differences were seen between herds. Antibody titres of milk cows on zerograzing farms were significantly lower than on comparable farms where animals were pastured. The need for further epidemiological work is stressed. In such work serology can be helpful.     

Variations of plasma leptin in show horses during a work season

Leptin is an adipocytokine mainly expressed by adipose tissue. Secretion of leptin in healthy animals is closely related to fat mass and metabolic activity. The aim of this study was to investigate plasma leptin variations, in relation to nutritional and exercise parameters in adult show horses during a work season. EDTA-blood samples were taken at rest from 37 Iberian horses. Body weight, body condition score and fat percentage determined by ultrasonic measurement of rump fat thickness were measured. Plasma leptin was determined with a multi-species RIA kit. Linear mixed effects model was used to assess relationship between plasma leptin and other biological parameters. Plasma leptin concentration was <12.6 ng/ml (mean = 2.8 ± 1.6 ng/ml) and was significantly higher during training periods (p < 0.0001) (4.5 ± 1.7 ng/ml) than in show periods (2.0 ± 1.1 ng/ml), despite a significant increase (p < 0.0001) in energy intake. The body weight remained almost constant. The plasma leptin concentrations were significantly affected by exercise (p < 0.0001), body weight (p = 0.04) and BCS (p < 0.0001), but were not affected by percentage of fat. In conclusion, the marked decrease in leptin values observed during a period of intense (i.e. excessive) exercise could result from an adaptation to cumulative alterations in energy balance, to exercise per se or to a combination of both.