【作者】 黄爱霞；

【导师】 吴天星； 卢立志；

【作者基本信息】 浙江大学 ， 动物营养与饲料科学， 2011， 博士

【摘要】 浙江省拥有丰富的地方鸡种资源,如何利用这些优秀的地方品种培育出适合消费者需求的优质肉鸡是优质鸡养殖业亟需解决的问题。本试验对浙江省主要鸡种的体尺、屠宰性能、肌内脂肪含量、肌苷酸含量、脂肪酸组成和氨基酸组成进行了分析。利用实时荧光定量PCR等技术,研究了leptin receptor(LEPR)在鸡胸肌中表达量及其与肌内脂肪的相关性,通过建立鸡前脂肪细胞培养模型,利用RNA干扰(RNAi)技术研究了LEPR基因在脂肪细胞分化和增殖过程中的表达规律,同时研究了与脂肪细胞分化相关的其他基因,如PPARγ等7个基因的表达规律,探讨了LEPR基因对脂肪代谢关键功能基因表达的影响及其调控脂肪代谢的机理。主要研究结果如下：1.体尺和屠宰性能测定结果结果表明,萧山鸡×广西黄鸡×仙居鸡(浙南黄鸡2号,ZNY2)配套系综合屠宰性能均优于其亲本,说明杂交优势明显。体尺和屠宰性能表型间呈中等或强的相关。2.肉质测定结果肌内脂肪：文昌鸡×哈伯特鸡(WHC)的肌内脂肪含量最高,仙居鸡(XJC)的最低,日龄对萧山鸡×仙居鸡(浙南黄鸡1号,ZNY1)胸肌肌内脂肪含量影响显著(P<0.05)；肌苷酸：萧山鸡×仙居鸡(浙南黄鸡1号,ZNY1)胸肌肌苷酸含量最高、萧山鸡(XSC)含量最低,80日龄和120日龄ZNY1肌苷酸含量差异不显著(P>0.05)；脂肪酸组成：各测定品种的肌肉脂肪酸组成之间存在一定的差异。不饱和脂肪酸相对含量文昌鸡(WCC)、萧山鸡×广西黄鸡×仙居鸡(浙南黄鸡2号,ZNY2)最高,多不饱和脂肪酸相对含量仙居鸡(XJC)的最高。日龄对ZNY1的脂肪酸组成影响差异不显著(P>0.05)；氨基酸组成：氨基酸及必需氨基酸总量ZNY2的最高,随着日龄的增加ZNY1氨基酸的总量有下降的趋势。3.胸肌中LEPR和UCP基因表达量与肌内脂肪含量的关系胸肌中LEPR基因表达量与肌内脂肪的含量呈中等程度的正相关；UCP基因含量与肌内脂肪含量呈弱的负相关。4.脂肪细胞中LEPR等基因的表达规律LEPR、UCP、PPARy、FAS、ATGL和Adiponectin基因的表达量随着脂肪细胞的分化逐渐升高,分别在第6、4、10、6、6、10天达到高峰；IGF-Ⅰ基因的表达量随着脂肪细胞的分化逐渐升高。5.LEPR基因干扰后PPARγ等基因的表达量LEPR基因干扰后UCP、PPARy、FAS、LPL和ATGL基因的表达量均显著下降(P<0.05),IGF-Ⅰ和Adiponectin含量均显著升高(P<0.05)。6.油酸对脂肪细胞中LEPR等基因的影响油酸诱导后LEPR、UCP、PPARy、LPL和Adiponectin的表达量上升,而ATGL和IGF-Ⅰ的表达量则降低。LEPR基因干扰后,油酸对脂肪细胞分化调控因子的诱导作用减弱,表明LEPR基因可能在这个过程中发挥了重要作用。更多还原

【Abstract】 In this experiment, we investigated the body size, slaughter traits and the chemical composition including intramuscular fat (IMF), inosinic acid, fatty acid and amino acid of chicken breast muscle, in order to make better use of the excellent genetic resources. The correlation of body size and slaughter traits was analyzed. The relationship between intramuscular fat contents and mRNA expressions of leptin receptor (LEPR) and uncoupling protein (UCP) genes expression were analysed. The effects of LEPR gene on the expression of fat metabolism related genes and the regulation mechanism of LEPR on the fat metabolism were studied by using real-time PCR, and RNA interference (RNAi). Results are as bellow:1. Body size and slaughter traits measurementThe body size and slaughter traits of five different chicken breeds and four hybrid breeds were measured. The crossbreeding improved the body size and slaughter traits of chicken.2. Analysis of chemical compostion of chicken meatThe Wenchang X Habote chicken (WHC) has the highest intramusculat fat content, and Xianju chicken (XJC) has the lowest; the Xiaoshan×Xianju chicken (ZNY1,120d) has the highest inosinic acid contents and Xiaoshan chicken (XSC) has the lowest. The relative contents of unsaturated fatty acid in chicken breast muscle of Wenchang chicken (WCC) and Xiaoshan X Guangxi yellow X Xianju chicken (ZNY2) are the highest. XJC has the highest relative contents of poly-unsaturated fatty acid (PUFA) contents. ZNY2 has the highest contents of amino acid and essential amino acid (EAA). The age of chicken can influence the contents of intramuscular fat in breast muscle of Xiaoshan X Xianju chicken significantly (P<0.05), while has no significant influence on inosinic acid content, fatty acid (P>0.05). The total amino acid contents tend to decrease with the age.3. Relationship between intramuscular fat contents and mRNA expressions of LEPR and UCP genes.The IMF content has middle correlation with LEPR gene and low negative correlation with UCP gene in the four detected chicken breeds.4. The expression characteristic of LEPR and other fat metabolism related genes in chicken adipocytesThe expression levels of LEPR, UCP, peroxisome proliferation-activated receptor y (PPARy), fatty acid sythase (FAS), adipose triglyceride lipase (ATGL) and Adiponectin genes increased with the adipocyte differentiation and reach the peak at 6,4,10,6,6,10 day respectively. And the abundance of IGF-I gene increased gradually with the differentiation of chicken adipocytes.5. Effects of LEPR gene knockdown on expression of UCP, PPARy, FAS, ATGL, Adiponectin and IGF-I genes in chicken adipocytesThe expressions of UCP, PPARy, FAS, LPL, ATGL genes decreased significantly after the silenceing of LEPR gene (P<0.05), while the expressions of IGF-I and Adiponectin increased significantly (P<0.05)6. Effects of oleic acid on expression of LEPR and other fat metabolism related genes in chicken adipocytesOleic acid can induce the expression of LEPR, UCP, PPARy, LPL, Adiponectin and suppress the expression of ATGL and IGF-I genes in chicken adipocytes. LEPR gene knockdown can weaken oleic acid’s effects on inducement of adipocyte differentiation related genes’expression. The results suggest that LEPR gene may play an important role in regulation of adipocytes differentiation induced by oleic acid.更多还原