【作者】 潘家强；

【导师】 王小龙；

【作者基本信息】 南京农业大学 ， 临床兽医学， 2005， 博士

【摘要】 通过大型临床防病试验,探索出了一套既能够有效防治肉鸡肺动脉高压综合征(pulmonary hypertension syndrome,PHS),又不影响肉鸡生产性能和胴体品质的早期限饲措施;应用细胞化学染色、免疫组织化学染色等技术,对比研究限饲组肉鸡和非限饲组肉鸡在肺血管显微形态、各型肺小血管占位比例以及体內一氧化氮(nitric oxide.NO)、脂质过氧化物水平和抗氧化酶活性的差异;并应用细胞培养、免疫细胞化学染色等技术,观察黄嘌呤/黄嘌呤氧化酶自由基发生系统和NO供体硝普钠对体外培养的肉鸡肺动脉內皮细胞和平滑肌细胞增殖和凋亡的影响,从而在体内和体外两个层次、整体和细胞两个水平上阐明了早期限饲、肉鸡肺小动脉重构和肺动脉高压综合征之间的关系,为通过早期限饲防制肉鸡PHS提供了理论依据。 试验Ⅰ 早期限饲对肉鸡肺动脉高压综合征发病率、肉鸡生产性能和腹脂率的影响。采用低温诱发肉鸡PHS,对比观察不同的早期限饲方法对于常温和低温条件下PHS的发病率、肉鸡生产性能和胴体品质的影响。在试验一中,限饲处理组肉鸡分别于7～14日龄或7～21日龄每天给料8h,对照组肉鸡全程自由采食。在试验二中,限饲组肉鸡分别于7～14日龄给予对照组肉鸡前一天饲料消耗量的60%或80%,对照组肉鸡自由采食。试验结果显示早期限饲能够降低肉鸡PHS的发病率,在低温条件下尤其明显;早期限饲改善了饲料效率,也未对肉鸡的胴体品质产生显著的影响,且适当限饲并不影响肉鸡的最终上市体重。这表明早期限饲是一种有效的控制肉鸡PHS的方法,值得在实际生产中推广应用。 试验Ⅱ 早期限饲降低肉鸡PHS发病率机理的研究:Ⅰ.对肉鸡肺血管重构的影响。观察早期限饲对常温和低温饲养条件下PHS的防治效果及对肉鸡肺小动脉显微形态学的影响。试验过程中连续采集肺组织进行弹力纤维染色,应用计算机图像分析系统测定肺小动脉平均中膜厚度(mMTPA)和相对中膜面积(WA/TA),计数肌性动脉(MA)、部更多还原

【Abstract】 Undergoing large-scale field trials, a set of early feed restriction regimes were established to reduce the pulmonary hypertension syndrome (PHS) morbidity without negative influence on the performance characteristics and carcass traits of broiler. Based on these facts, the cytochemistry staining techniques, immunohistochemical staining techniques etc were used to investigate the differences on the micro morphological changes and percentages of different types of pulmonary arterioles in broiler as well as differences on the nitric oxide (NO), oxygen free radicals concentration and enzymatic antioxidant activity in vivo between feed restricted and unrestricted broilers. The technique of cell culture and immunocytochemical staining method etc were employed to investigate the xanthine/ xanthine oxidase oxygen free radical generating system and the sodium nitroprosside (SNP), a NO donor on the proliferation and apoptosis of cultured pulmonary artery endothelial cells and smooth muscle cells of broiler in vitro. These works clarified the relationship between early feed restriction, pulmonary arterioles remodeling and pulmonary hypertension in broilers and provided theoretical basis of the feed restriction technique for controlling the PHS incidence.Test I Effects of early feed restriction on the pulmonary hypertension syndrome morbidity, performance and abdominal fat pad ratio in commercial broilers. Broilers were exposed to low ambient temperature to induce PHS. Experiments were conducted to investigate the effects of different early feed restriction regimes on the PHS morbidity, performance characteristics and meat quality of commercial broilers under normal or low ambient temperature. In experiment 1, the restricted chicks were fed 8 hours per day either from day 7 to day 14 or from day 7 to day 21, while the controlled chicks were fed ad libitum. In experiment 2, the restricted chicks were fed 80% or 60% of previous 24 hourfeed consumption of full-fed controls for 7 days from day 7 to day 14, while the full-fed controls were fed ad libitum all through the experiment. The results showed that early feed restriction treatments reduced PHS morbidity, which was more significant under low temperature. Feed conversion ratios were lower in fed restricted broilers than in full fed controls. Early feed restriction had no obvious effects on abdominal fat pad ratio, and proper feed restriction did not affect the final body weight of broiler on market age. These results indicated that early feed restriction was an effective method to control the incidence of PHS in broiler.Test II Study on the mechanism of early feed restriction reducing the incidence of PHS in broiler: I. Effects on the pulmonary vascular remodeling in broilers.Experiments were conducted to investigate the effects of early feed restriction on the incidence of PHS and microstructure of pulmonary arterioles in broiler under normal and low ambient temperature. Lung samples were taken continuously and stained for elastin. The vessel wall area to vessel total area ratio (WA/TA) and mean media thickness in pulmonary arterioles (mMTPA) were measured using microscopic image analysis software. The muscular arterioles (MA), partially muscular arterioles (PMA) and non- muscular arterioles (NMA) were counted and the percentages of thick-walled peripheral lung vessels (%TWPV) were calculated. The PHS morbidity were significantly increased in low temperature treated broiler. Early feed restriction markedly reduced the PHS morbidity compared with the ad libitum feeding chicks. Low ambient temperature significantly increased the WA/TA, mMTPA and %TWPV in pulmonary arterioles, while early time feed restriction markedly decreased the WA/TA, mMTPA and %TWPV. It was concluded that feed restriction during the early period was of benefit to reduce PHS morbidity in broiler, and the attenuated pulmonary vascular remodeling characterized by pulmonary arterioles hypertrophy and muscularization might be involved in the underlying mechanisms.Test III Study on the mechanism of early更多还原