【作者】 任灵芝；

【导师】 赵茹茜；

【作者基本信息】 南京农业大学 ， 基础兽医学， 2008， 硕士

【摘要】 本实验采用蛋内注射的方式来探讨胚胎发育早期大豆黄酮处理对雏鸡生长性能的影响,并通过测定下丘脑和肝脏生长相关基因的表达,初步探讨了蛋内注射大豆黄酮影响雏鸡生长的作用机理。1蛋内注射大豆黄酮对仔鸡早期生长的影响选取三黄矮D种蛋孵化,在第7胚龄时随机分为2组,分别注射100μL白油和1 mg/mL大豆黄酮白油溶液作为对照组和试验组,出雏后,记录育雏期每周体重,于1和21日龄采样。结果表明蛋内注射大豆黄酮对雏鸡初生重没有显著影响,但此后雏鸡表现较高的生长速度,21日龄体重显著高于对照组（P＜0.05）。1日龄时,大豆黄酮组雄性雏鸡腓肠肌重和腓体比显著降低,雌性雏鸡肝脏指数显著升高,胸浅肌重显著降低;而21日龄时,大豆黄酮组雄性雏鸡肝脏指数显著降低,腓肠肌重、腓体比、胸浅肌重和胸体比显著升高,雌性雏鸡肝脏指数显著降低,腓肠肌重显著升高。用放射免疫分析法测定出生后血清T₄、T₃、fT₃和Estradiol水平。结果显示蛋内注射大豆黄酮对1日龄雏鸡血清激素水平无显著影响。21日龄雏鸡血清T₄水平没有变化,但大豆黄酮显著降低了雄性雏鸡T₃水平,同时也显著降低了雌性雏鸡fT₃水平（P＜0.05）;21日龄大豆黄酮组雌性雏鸡血清雌二醇水平显著高于对照组（P＜0.05）。2蛋内注射大豆黄酮对仔鸡生长相关基因表达的影响用相对定量实时荧光PCR方法检测21日龄肝脏GHR、IGF-I和IGF-IR以及下丘脑SS、TRH、CRH和FTO mRNA表达。结果显示,蛋内注射大豆黄酮显著上调了肝脏GHR和IGF-I mRNA表达（P＜0.05）,但对肝脏IGF-IR mRNA的表达无显著影响;大豆黄酮显著降低了雄性雏鸡下丘脑SS mRNA,但对雌性则无此作用;大豆黄酮组雌性雏鸡TRH mRNA显著升高（P＜0.05）,雄性雏鸡有升高的趋势（P=0.07）:大豆黄酮对雏鸡下丘脑CRH mRNA表达无显著影响;下丘脑FTO mRNA表达大豆黄酮组显著高于对照组（P＜0.05）;以上结果表明:蛋内注射大豆黄酮可促进雏鸡生长,这种促生长作用与下丘脑和肝脏生长相关基因表达的变化有关。更多还原

【Abstract】 In this study,in ovo injection of daidzein was used to investigate the effect of early embryonic daidzain exposure on posthatch growth of broiler chickens.Serum levels of thyroid hormones and growth-related genes in hypothalamus and liver were analyzed to reveal the underlying mechanism.1 Effect of daidzein administration in ovo on early posthatch growthOn day 7 of embryonic age,fertile eggs of Sanhuang small D were randomly allocated to Control and Daidzein groups,which were injected with 100μL of white mineral oil or 1 mg/ml daidzein-oil solution.Body weight was recorded weekly.At day 1 and 21 posthatch （D1 and D21）,blood and tissue samples were collected for further analysis.No significant difference was observed on hatch weight between these two groups,but the Daidzein group exhibited faster growth rate after hatching,which resulted in significantly greater body weight than that of control at D21（P＜0.05）.On D1,gastrocnemius weight and gastrocnemius ratio were all reduced in males,yet daidzein significantly increased liver index and reduced pectoralis major weight in females.On D21,however,daidzain administration in ovo significantly reduced liver index but increased gastrocnemius weight, gastrocnemius ratio,pectoralis major weight and pectoralis major ratio in males,and reduced liver index but increased gastrocnemius weight in females.The serum T₄,T₃,fT₃ and Estradiol were tested with RIA.Results indicated that there was no significant changes on serum hormone levels at 1D.On D21,there is no differernce were detected on T₄,and daidzein administration significantly reduced T3 level in males and fT3 in females.Daidzein group had significantly higher E level in females.2 Effect of daidzein administration in ovo on expression of growth related genes in hypothalamus and liverHepatic GHR,IGF-I and IGF-IR and hapathalamic SS,TRH and FTO mRNA expression were determined with relative quantitative real-time PCR on D21.Daidzein group had significantly higher hepatic expression of GHR and IGF-I but similar IGF-IR mRNA compared with Control group.In hypothalamus,daidzain administration in ovo significantly reduced SS mRNA expression in male chickens,but not in females.Besides, daidzain in ovo tended to enhance TRH transcripts in males（P=0.07） and significantly increased its expression in females.No difference was found between the two groups on CRH mRNA expression.Interestingly,FTO mRNA in hypothalamus was significantly enhanced by daidzain treatment.These results indicate that embryonic exposure to daidzein exerts a long-term effect on posthatch growth by modification of growth-related gene expression in liver and hypothalamus of chickens.更多还原