Comparative physiological study on environmental temperature effect influencing development of thermoregulatory competence in birds.

1.鸡呼吸窦性心律失常和心率昼夜节律的发展。在将气体交换器从绒毛膜尿囊切换到肺部的外置（EP）胚胎和新孵化的小鸡中，同时测量呼吸活动和瞬时心率（IHR），证明了鸡呼吸窦性心律失常的发展。此外，在孵化后一周内长期测量IHR阐明了鸡心率（HR）昼夜节律的发展。与鸡相比，鸭和鸸鹋的HR昼夜节律不明显，它们的昼夜HR变化似乎是由摄食或日常活动引起的。鸡胚胎心率变异性的发展和对环境氧改变的反应。同时测定肉仔鸡和白来角鸡的胚胎HR变异性和功率谱分析表明，两种品系的胆碱能变时控制发育无差异。此外，我们还研究了预插管、预内插管（IP）、IP和EP胚胎对环境氧（缺氧和高氧）改变的HR反应，发现预插管和内插管胚胎之间存在差异。鸡、鸭和鸸鹋吸热心率反应的研究进展。在鸡的实验中，已经证明了不同的环境温度对雏鸡的吸热HR反应没有影响，而孵蛋温度也不影响吸热HR反应的早期发育。对环境温度变化10℃的吸热HR反应出现在肉鸡孵化后1天、鸭孵化后不久和鸸鹋拔毛期。此外，发现肉仔鸡和白来角鸡的吸热HR反应发育不同，这可能是由于肉鸡生长速度快的遗传选择所致。

1.Development of respiratory sinus arrhythmia and heart rate circadian rhythms in chickens.Simultaneous measurements of respiratory activities and instantaneous heart rate (IHR) in externally pipped (EP) embryos which switch gas exchanger from the chorioallantois to the lung and also in newly hatched chicks evidenced development of respiratory sinus arrhythmia in chickens. In addition, long-term measurement of IHR during a week post-hatch elucidated development of heart rate (HR) circadian rhythms in chickens. In ducks and emu, HR circadian rhythms were not evident as compared with chickens and their diurnal and nocturnal HR variations seemed to be caused by feeding or daily activities.2.Development of heart rate variability and responses to altered ambient oxygen in chicken embryos.Simultaneous measurements of embryonic HR variability both in broiler and white leghorn chickens and power spectrum analyses evidenced that development of cholinergic chronotropic control was not different between both strains. In addition, HR responses to altered ambient oxygen (hypoxia and hyperoxia) were investigated in young pre-pipped, pre-internally pipped (IP), IP and EP embryos and found to be different between pre-pipped and pipped embryos.3.Development of endothermic heart rate response in chickens, ducks and emu.In chickens, it was evidenced that sequence of exposure of hatchlings to altered ambient temperatures did not affect the endothermic HR response and brooding temperatures did not affect early development of endothermic HR response. The endothermic HR response to alteration of 10℃ in ambient temperature appeared in a day post-hatch in broiler chickens, soon after hatching in ducks and during external pipping period in emu. In addition, it was found that development of endothermic HR response was different between broiler and white leghorn chickens, which might be due to genetic selection of broiler chickens which grew fast.