中文摘要：

应用低温环境诱发肉鸡肺动脉高压综合征（PHS）,观察早期限饲对PHS的防治效果及对肺小动脉显微形态学的影响。试验Ⅰ：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。试验Ⅱ：限饲组肉鸡于7-14日龄分别给予自由采食对照组肉鸡前一天饲料消耗量的60%或80%。连续采样测定肺小动脉平均中膜厚度（mMTPA）、肺小动脉相对中膜面积（WA/TA）和肺厚壁末梢血管百分比（TWPV%）。结果显示,早期限饲显著降低了PHS发病率;低温显著升高了肉鸡WA/TA、mMTPA和TWPV%,而早期限饲处理则显著降低了WA/TA、mMTPA和TWPV%。提示：早期限饲能够有效防治肉鸡PHS,而抑制以肺小动脉管壁肥厚和肺血管肌型化为特征的血管重构可能是其重要机制之一。

英文摘要：

Broilers were exposed to low ambient temperature to induce pulmonary hypertension syndrome（PHS）.Experiments were conducted to investigate the effects of early feed restriction on the incidence of PHS and the microstructure of pulmonary arterioles in broiler.In Experiment Ⅰ,the feed restricted chicks were fed 8 hours per day either from 7 day-old to 14 day-old or from 7 day-old to 21 day-old,while the controlled chicks were fed ad libitum.In Experiment Ⅱ,the feed restricted chicks were fed 80% or 60% of previous 24 hours feed consumption of full-fed controls for 7 days from 7 day-old to 14 day-old.Samples were taken continuously to measure the vessel wall area to vessel total area ratio（WA/TA）,the mean media thickness in pulmonary arterioles（mMTPA）and the percentage of thick-walled peripheral lung vessels（TWPV%）.The results showed that early feed restriction markedly reduced the PHS morbidity.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 could prevent the occurrence of PHS,and the attenuated pulmonary vascular remodeling characterized by pulmonary arterioles hypertrophy and muscularization might be involved in the underlying mechanisms.