Breed Characters Of Tibetan Chicken

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.