Hohtola E, Hissa R, Pyörnilä A, Rintamäki H, Saarela S
Department of Zoology, University of Oulu, Finland.
Physiol Behav. 1991 Mar;49(3):563-7. doi: 10.1016/0031-9384(91)90281-r.
Japanese quail were equipped with intraperitoneal transmitters for telemetric measurement of body temperature (Tb) and activity. Food deprivation at + 24 degrees C for four days induced a well-defined nocturnal hypothermic response. The normal day-night difference (about 1 degrees C) in Tb increased 1 degrees C per day, reaching 5 degrees C on the fourth night of fast. Nocturnal motor activity decreased during the fast, while daytime activity first increased and then returned to the original level by the end of the fasting period. A strong correlation between Tb and motor activity was found during scotophase (r = .91) but not during photophase (r = .02). At + 4 degrees C, where food was deprived for two days, the level of hypothermia was not different from that at + 24 degrees C, but birds fasting in the cold reached the hypothermic level more rapidly. In control birds, the decrease in Tb at the beginning of scotophase was independent of ambient temperature. In the combined data, the level of hypothermia correlated strongly with body mass loss (r = .90), which shows that quail can directly or indirectly sense the amount of body energy reserves. This is the first report of hypothermia in a fasting gallinaceous bird. The consistent level of hypothermia at varying ambient temperatures suggests that either nonenergetic costs or phylogenetic constraints prevent deeper hypothermia in cold. Accordingly, the regulation of hypothermia cannot be explained by using only energetic arguments.
给日本鹌鹑植入腹腔内发射器，用于遥测体温（Tb）和活动情况。在24摄氏度环境下禁食四天会引发明确的夜间低温反应。Tb的正常昼夜温差（约1摄氏度）每天增加1摄氏度，在禁食的第四晚达到5摄氏度。禁食期间夜间运动活动减少，而白天活动先增加，到禁食期末又恢复到原来水平。在暗期发现Tb与运动活动之间有很强的相关性（r = 0.91），但在光期则没有（r = 0.02）。在4摄氏度环境下禁食两天，低温程度与24摄氏度时并无差异，但在寒冷环境中禁食的鸟类达到低温水平的速度更快。在对照鸟类中，暗期开始时Tb的下降与环境温度无关。综合数据显示，低温程度与体重减轻密切相关（r = 0.90），这表明鹌鹑能够直接或间接感知体内能量储备量。这是关于禁食鸡形目鸟类低温现象的首次报道。在不同环境温度下低温程度保持一致，这表明非能量成本或系统发育限制因素阻止了在寒冷环境中出现更深程度的低温。因此，仅用能量方面的观点无法解释低温的调节机制。
