【作者】 周杰；

【导师】 赵茹茜； 陈杰；

【作者基本信息】 南京农业大学 ， 基础兽医学， 2003， 博士

【摘要】 1 猪脂肪组织发育的神经内分泌调节 为了探讨猪脂肪组织发育的神经内分泌和分子生物学机制，本研究以肥胖型二花脸猪和瘦肉型大白猪为动物模型，通过相对定量RT-PCR方法，以18S rRNA作内标，研究脂肪组织中GH-R、IGF-1、IGF-IR和Leptin的基因表达，以及下丘脑中Ob-Rb的基因表达，分析其发育性变化的规律及品种特点和性别差异，探讨生长轴对脂肪组织发育的作用机理，以及Leptin和下丘脑Ob-Rb与猪体脂沉积和繁殖特性的关系。 结果表明：脂肪组织中GH-R、IGF-1和IGF-IR mRNA的表达有明显的发育性变化，其中IGF-1和IGF-IR mRNA的发育模式基本相同，而与GH-R的发育模式不同。IGF-Ⅰ mRNA表达存在品种和性别差异，二花脸猪高于大白猪，公猪高于母猪。GH-R mRNA表达存在品种差异，二花脸猪高于大白猪。结果提示：猪脂肪组织中IGF-1的表达可能不依赖或部分依赖于GH，GH-R和IGF-1的品种差异可能是两品种猪脂肪沉积规律不同的主要原因之一。 脂肪组织中Leptin mRNA的表达有明显的发育性变化，随日龄增加而增高，二花脸猪显著高于大白猪，母猪显著高于公猪，与血清Leptin水平的发育性变化呈高度正相关。而下丘脑中Ob-Rb mRNA的表达呈现明显不同的发育模式及品种特点，在出生后逐渐下降，然后逐渐回升，断乳后又逐渐下降，二花脸猪在120-180日龄又逐渐回升。大白猪Ob-Rb的基因表达在总体上高于二花脸猪。结果提示：二花脸猪和大白猪脂肪组织中Leptin的基因表达与脂肪沉积相关，而下丘脑Ob-Rb的基因表达可能与繁殖性能相关。 2 生理调节剂对猪脂肪组织的调控及其机制 众所周知，生长激素可减少脂肪沉积，但其作用机理不甚清楚。本试验中生长猪经重组猪生长激素注射处理后，其皮下脂肪细胞GH-R、IGF-1和IGF-IR mRNA丰度显著增加，而Leptin mRNA丰度显著减少(P＜0.05)。结果提示，生长激素不仅可以直接调节脂肪组织，还有可能通过脂肪GH－R介导产生IGF－Ⅰ，以旁(自)分泌形式调节脂肪组织的代谢。周杰猪脂肪组织发育和体脂沉积的神经内分泌及免疫调控 C几000的有效成分为半耽胺，它作为生长抑素的耗竭剂，可促进动物生长.但之对脂肪沉积的影响尚不清楚.肥育猪经CT200O饲喂后，增重提高，胭体脂率和6、/肋背膘厚下降，血清LePtin水平降低，血清TNF一a水平升高，血清insulin水平不受彩响.试验猪脂肪细胞LePti乓mRNA丰度显著减少，而GH一R、IGF一1、IGF一IR mRNA丰度以及下丘脑ob一Rb mRNA丰度无显著变化。结果提示，与促进生长的作用不同，二长000对脂肪组织的作用是抑制脂肪沉积.3脂肪细胞膜免疫对脂肪沉积的影响 脂肪细胞膜免疫能降低动物脂肪沉积，改善胭体品质.目前主要通过杭血清被动免疫动物，呼尸黄抗体应用的较少，特别是口服脂肪细胞膜蛋白卵黄杭体对哺乳动物脂防沉积的影响尚未见报道.本试验矛!」用猪脂肪细胞膜蛋白制备卵黄杭体，并进行卵黄坑体生物学效应试验。结果表明:用脂肪细胞膜蛋白为杭原主动免疫蛋鸡，蛋鸡四免后.卵黄杭体效价达1:12800以上;蛋鸡五免后，卵黄抗体可保持高效价60天以上。卵黄抗体与其他细胞膜有较弱的交又反应。 卵黄抗体免疫显著降了氏肠系膜、子宫周和肾周脂肪的沉积;但对体重和摄食量无显著影响，口服处理的效果优于皮下处理.口服卵黄杭体可降了氏血清甘油三醋，提高血清游离脂肪酸浓度，降低血清Lep血、胰岛素和TNF一a水平，降低脂肪组织DNA含童.同时显著降低脂肪组织LePtin mRNA表达，降低子宫周脂中凋亡相关基因Bcl一2和Bax mRNA表达，上调下丘脑ob一Rb mRNA表达。结果提示:口服脂肪细胞膜卵黄杭体降低体脂沉积的作用途径可能是:1、直接溶解脂肪细胞，抑制脂肪细胞增殖;2、通过脂肪代谢的改变，间接减少脂肪沉积.更多还原

【Abstract】 1 Neuroendocrine regulation of Porcine Adipose Tissue DevelopmentIn order to research the neuroendocrine and molecular mechanisms of adipose tissue development, purebred male and female Erhualian pigs, male Large White pigs with significant differences in growth rate, fat deposition and reproductive performance were employed in present study to investigate the developmental changes of GH-R, IGF-1, IGF-IR and Leptin mRNA expression in dorsal subcutaneous adipose tissue and Ob-Rb mRNA expression in hypothalamus by RT-PCR with 18S rRNA as internal standard. Breed difference and sexual dimorphism of the expression patterns of above mentioned genes were also investigated in this research.Results showed that the GH-R, IGF-1 and IGF-IR mRNA expression in adipose tissue followed specific developmental pattern. The developmental change of IGF-1 and IGF-IR mRNA were similar, but were different to that of GH-R. The expression of IGF-1 mRNA were breed different and sexual dimorphic, which was higher in Erhualian boars than in Large White boars, and higher in Erhualian boars than in gilts. The GH-R mRNA expression was higher in Erhualian boars than in Large White boars. The results suggest that the IGF-1 mRNA expression in adipose tissue may independent or partly dependent with GH, and the different patterns of GH-R and IGF-1 gene expression between two breeds may contribute to different phenotypes in adipose tissue deposition.Leptin mRNA expression in adipose tissue increased with age and displayed both sex and line differences. In Erhualian pigs, females expressed higher Leptin mRNA compared with males, and Erhualian boars showed higher abundance of Leptin mRNA than Large White boars. Serum Leptin levels were in good agreement with adipose Leptin mRNA, displaying similar sex and line differences. In contrast, expression of Ob-Rb mRNA in hypothalamus exhibited a distinctive pattern, decreased gradually after birth, and then increased till weaning. After weaning, Ob-Rb gene expression decreased gradually with age but raisedgradually again from 120 to 180 days of age in Erhualian pigs. The expression of Ob-Rb mRNA was higher in Large White pigs than that in Erhualian pigs (P<0.01). The results suggest that the serum Leptin level and Leptin gene expression in adipose tissue highly correlate with adiposity, while Ob-Rb gene expression in hypothalamus is more related with reproductive traits.2 Regulation of porcine adipose tissue by physiological regulators and mechanisms involvedGH can decrease adipose tissue depots, but its mechanism is not yet clear. The relative abundance of GH-R, IGF-1 and IGF-IR mRNA in adipose tissue of growing pigs were increased significantly by rpGH administration, while the expression of Leptin mRNA in adipose tissue were decreased. These results suggest that rpGH could not only regulate adipose tissue directly, but also through the mediation of enhanced IGF-1 secretion in adipose tissue, act locally via the IGF-IR in an autbcrine/paracrine manner.The functional component of CT2000 is cysteamine-a somatostatin inhibiting agent, which can promote growth in animals. However, the effect of cysteamine on adipose tissue depots is not very clear. CT2000 treatment enhanced the body weight gain of finishing pigs, decreased the adiposity index and back-fat thickness in 6,7 rib, decreased the serum Leptin concentration, increased serum TNF- a . CT2000 also down-regulated the relative abundance of Leptin mRNA in dorsal subcutaneous adipose tissue (p<0.05). But no difference in serum insulin level, the relative abundance of GH-R, IGF-1, IGF-IR mRNA in dorsal subcutaneous adipose tissue and Ob-Rb mRNA at hypothalamus between CT2000 treated and control group was found. These suggest that CT2000 can improve carcass quality of finishing pigs apart from its growth-promoting action.3 Effect of yolk antibody against pig adipocyte plasma membrane (APM) protein on adipose tissue depositionImmunization against APM can reduce body fat deposition and improve carcass quality. Anti-sera have b更多还原