【作者】 强巴央宗；

【导师】 谢庄；

【作者基本信息】 南京农业大学 ， 动物遗传育种与繁殖， 2008， 博士

【摘要】 藏鸡是分布于我国青藏高原的原始小型地方鸡种,本文通过现场调查和抽样检测等方法研究藏鸡种质特性,分析藏鸡体型外貌和生产性能多样性,并用10个微卫星位点从DNA分子水平分析藏鸡遗传多态性.针对高原种蛋孵化率低的问题进行了系列孵化实验,分析人工孵化的种蛋贮存时间、孵化温度,湿度等条件.为了分析VEGF基因在藏鸡胚胎低氧适应中的作用,本文用测序法比较藏鸡和矮小隐性白鸡VEGF基因mRNA序列差异。并比较常氧（O₂ 21%）和低氧（O₂ 13%）浓度孵化环境中,胚胎尿囊绒毛膜（CAM）组织VEGF基因mRNA表达差异.为了了解藏鸡开发利用价值,本文选用非线性生长模型分析了藏鸡及隐形白鸡在高海拔环境中生长性能,屠宰特定其肉用性能,从肉物理性状和氨基酸、肌苷酸含量分析藏鸡肉用性能,从蛋的常规营养成分和微量元素含量分析藏鸡蛋用性能.结果如下:（1）藏鸡生境低压、低氧、严寒等恶劣气候,处于半野生生活状态,具有适应高原气候、觅食能力强、耐粗饲、体型外貌和生活习性与红色原鸡非常近似、人工选择程度低等特点.（2）藏鸡人工孵化最佳孵化温度为1-6天为37.68℃;7-14天为37.65℃;15-20天为37.56℃;21天为37.48℃.高原孵化种蛋保存时间不超过7天,贮存温度12-15℃。湿度保持在75-80%,种蛋大头向上.藏鸡受精蛋孵化率88.9%,拉萨白鸡受精蛋孵化率77.5%,隐性白鸡50.7%,藏鸡×隐性白鸡种蛋55.7%,隐性白鸡×藏鸡种蛋63.2%,农大3号矮小蛋鸡54.3%,藏鸡×农大3号矮小蛋鸡种蛋74.7%.（3）根据残差平方和（RSS）和复相关指数（R²）,logisitic模型为模拟高海拔鸡生长过程的较优模型,藏公、母鸡logistic模型拟合的极限体重分别为711.2g和646.6g;拐点周龄分别为12.72和12.32周;拐点体重分别为415.1g和323.3g.引进到高原的隐性白鸡极限体重公、母鸡分别为1243.4g和972.1g,拐点周龄分别为12.51和11.81周,拐点体重分别为621.70g和486.05g.（4）藏鸡公、母屠体率分别为88.95%和88.74%,半净膛率分别为75.55%和74.65%,全净膛率分别为56.30%和55.34%,胸肌率分别为15.00%和15.97%,腿肌率分别为23.69%和23.09%),胸肌滴水损失分别为2.68%和2.62%,肉色分别为3.52和3.74,剪切力值分别为2.95和3.08kg,熟肉率分别为72.03%和71.12%,氨基酸质量分数分别为20.67%和19.78%,肌苷酸分别为2.32和2.50 mg/g.藏鸡具有肉质鲜美的特征,是发展高原特色、优质养殖业的良好品种.（5）藏鸡蛋的营养成分,铁、铜、锌等具有重要生理功能的微量元素以及粗蛋白、粗脂肪含量均高于普通鸡蛋,具有比普通鸡蛋更高的营养价值.（6）藏鸡具有体型小、身体长、胫较高,羽色、冠形、体尺等体型外貌形状具有丰富的多态性。藏鸡微卫星位点遗传多样性丰富、杂合程度高、遗传变异大,群体间存在一定的遗传差异.（7）VEGF基因序列在藏鸡与矮小隐性白鸡之间相当保守,低氧刺激使藏鸡和矮小隐性白鸡CAM组织VEGF基因表达均上调,矮小隐性白鸡上调程度明显大于藏鸡.藏鸡在低氧环境中CAM组织中VEGF基因表达表现一定程度的增加,有利于血管形成,表现对低氧环境的适应.总之,藏鸡无论从表型水平还是从分子水平都是具有丰富遗传多样性的小型地方鸡种,其VEGF基因低氧表达模式具有适应高海拔低氧环境的特征.藏鸡生长缓慢,屠宰性能不高。但胸肌和腿肌率高,氨基酸含量丰富,必需氨基酸和鲜味氨基酸比例大,蛋营养价值高,是发展高原特色、优质养殖业的良好品种.更多还原

【Abstract】 Tibetan chicken is an original indigenous breed with small body size in the Tibetan plateau of China. In present study, breed characteristics of Tibetan chicken were researched with local inquiry and sample measurement, and its variety was analyzed with body size, performances, and 10 microsatellites markers in genomes DNA. Because of the low hatchability at high altitude, a set of incubation experiments were carried to analyze the optimal conditions of artificial incubation, such as eggs store time, incubator room temperature and relative humidity, ect. In order to research function of VEGF gene on adaptation to hypoxia in Tibetan chicken embryo, the mRNA of VEGF gene was sequenced and measured by quantitative expression in CAM tissue of embryos in Tibetan and Dwarf Recessive White chickens that were incubated at conditions of normal oxygen （O₂ 21%） and low oxygen （O₂ 13%）. Furthermore, In order to research the value in meat use the growth of Tibetan and Recessive White chickens raised at hith altitude enviroment were analyzed with nonlinear models, and meat traits including meat physical characters and amino acid and ionsine monophosphat acid contents were measured. The nutrition component and microelement content of Thibetan chicken eggs were determined to evaluate its value in egg use. The results were as following:（1） Tibetan chickens with live state of half-wild had habitation of hypobaric hypoxia and chilliness, and charactered adaptation to altiplano environment, high ability of look for food, endurance to coarse feeding, similar to red jungle fowl in bode size and live habit.（2） The optimal temperature of incubator room in Tibetan chicken incubation was 37.68℃for day 1 to 6, 37.65℃for day 7 to 14, 37.56℃for day 15 to 20, and 37.48℃for day 21. For incubation at high altitude the eggs store time was less than 7 days, store temperature 12 to 15℃, relative humidity 75% to 80%, and the blunt end of eggs was up. At 2900 m altitude, hatchability of fertile eggs was 88.9% in Tibetan chicken, 77.5% in Lasa White chicken, 50.7% in Recessive White chicken, 55.7% in Tibetan×Recessive White chickens, 63.2% in Recessive White×Tibetan chickens, 54.3% in Nongda No. 3 Dwarf chickens, and 74.7% in Tibetan×Nongda No. 3 Dwarf chickens.（3） Comparing based on residual sum of squares （RSS） and correlation coefficient （R²）, it was found that logistic model was superior for fitting the growth courses of Tibetan and lowland chickens. The male and female Tibetan chickens had 711.2 and 646.6 g in final weight, 12.72 and 12.32 wk in inflection point time, 415.1 and 323.3 g in inflection point weight, respectively. The male and female Recessive White chickens introduced to high altitude had 1243.4 and 972.1 g in final weight, 12.51 and 11.81 wk in inflection point time, 621.70 and 486.05 g in inflection point weight, respectively.（4） The male and female Tibentan chickens had 88.95% and 88.74% in carcass yield, 75.55% and 74.65% in half eviscerated yields, 56.30% and 55.34% in eviscerated yields, 15.00% and 15.97% in breast muscle yields, 23.69% and 23.09% in leg muscle yields, 2.68% and 2.62% in water dripping loss, 3.52 and 3.74 in meat color, 2.95 and 3.08 kg in meat shearforce, 72.03% and 71.12% in cooking ratio, 20.67% and 19.78% in amino acids contents, 2.32 and 2.50 mg/g in ionsine monophosphat acid contents, respectively. Tibetan chickens had low carcass and eviscerated yields, but had high breast and lag muscle yields, and essential amino acid and testy amino acid contents. Therefore, Tibetan chicken is a good breed for developing high quality especial animal production in high altitude areas.（5） Tibetan chicken eggs had higher nutrition than common eggs in Fe, Cu, Zn, ect., and cross protein and cross fat that have importance physiological function.（6） Tibetan chicken population had abundant variety in feather colour, comb shape, body size, and microsatellite loci, and had high heterozygosity and certain genetic variance within the popution.（7） The mRNA sequence of VEGF gene was conservative between Tibetan and Drwarf Recessive White chickens. Hypoxia-induced VEGF up-regulation occurred in CAM tissue for both breeds. However, the extent of up-regulation was significantly higher in Dwarf Recessive White than that in Tibetan chickens. Tibetan chickens had hypoxia induced VEGF mRNA expression to a certain degree, which made for angiogenesis and adaptation to hypoxic environment.At all, Tibetan chicken is a small size breed with aboundent variety in phenotype and molecule genotype. The hypoxia induced expression of VEGF gene in Tibetan chickens had characteristic of adaptation to hypoxia at high altitude. Tibetan chickens had low growth rate and carcass yields, but had high breast and lag muscle yields, and essential amino acid and testy amino acid contents, and its eggs had high nutrition values. So, Tibetan chicken is a good breed for developing high quality and especial animal production in high altitude areas.更多还原