Comparative study on respiratory and circulatory functions in avian eggs

1.在不妨碍蛋壳气体交换的条件下，用心阻抗法测定了鸡胚胎心率（HR）的发育规律。此外，还观察了胚胎HR对10%O_2和100%O_2指数的反应。与HR对低氧敏感性的显著发育变化相反，HR对高氧反应不明显，提示HR无低氧驱动.用声学心动图（ACG）无创性地测定了鸵鸟胚胎HR的发育模式，并与蛋壳气导（G）和蛋重进行了相关性研究。它们与卵块无关。然而，高G蛋的胚胎具有高HR与低和中G蛋相比，尽管它们在高湿度孵化器中孵育以保持足够的水分从蛋中损失。一年后的进一步实验表明，孵化器湿度影响高G蛋中胚胎发育的HR。在人工孵化的最后15天，用ACG法测定了鸸鹋胚胎HR的发育模式。在测量的前5天期间，6个胚胎的平均模式保持在约170 bpm，并且在剩余的10天期间降低到约140 bpm。在辅助体外吹打期间可以检测到ACG。本文测定了早熟鸡（N=9）和晚期、半晚期鸡（N=20）的胚胎心率与鲜蛋量的异速生长关系。早熟鸟80%孵化期HR的异速生长关系与最大HR的异速生长关系相似（即，内部或外部HR）。在室兰工业大学举办了关于动物心律的国际研讨会，包括两名合作者（Ar教授和Burggren教授）在内的22名海外参与者，以总结和进一步促进国际科学研究。

1. Developmental patterns of embryonic heart rate (HR) in chickens were determined by impedance-cardiography during day 3-9 of incubation without impeding gas exchange through the eggshell. Additionally, responses of embryonic HR to 10% O_2 and 100% O_2 exponsoures were investigated. In contrast to the marked developmental changes in hypoxic sensitivity of HR,the HR showed little response to hyperoxia, suggesting no hypoxic drive to HR.2. Developmental patterns of HR in ostrich embryos were determined noninvasively by acoustocardiogram (ACG) in relation to eggshell gas conductance (G) and egg mass. They were not related to egg mass. However, embryos of high G eggs had high HR compared with those of low and medium G eggs, despite that they were incubated in a high humidity incubator to maintain adequate water loss from the eggs. Additional experiments mad one year later elucidated that the incubator humidity affected the HR of embryos developming in high G eggs.3. Developmental patterns of HR in emu embryos were also determined by ACG during the last 15 days of artificial incubation. The averaged pattern in 6 embryos was kept at about 170 bpm during the first 5 days of measurement and decreased to about 140 bpm during the remaining 10 days. The ACG could be detected during the assisted external pipping period.4. The allometric relations of embryonic HR with fresh egg mass were determined in precocial (N=9) and altricial and semi-altricial birds (N=20) . The allometric relation of HR at 80% of incubation period in precocial birds was similar to that of maximum HR (i.e., internal or external HR) in altricial birds.5. International symposium on cardiac rhythms in animals was held in Muroran Institute of Technology having 22 overseas participants including two collaborators (Prof. Ar and Prof. Burggren) to conclude and promote further the international scientific research.