Groscolas R, Decrock F, Thil M A, Fayolle C, Boissery C, Robin J P
Centre d'Ecologie et Physiologie Energétiques, Centre National de la Recherche Scientifique, 67087 Strasbourg Cedex, France.
Am J Physiol Regul Integr Comp Physiol. 2000 Dec;279(6):R2104-12. doi: 10.1152/ajpregu.2000.279.6.R2104.
This study is directed toward understanding the process of feeding stimulation ("refeeding signal") that has been suggested to operate below a body mass threshold or critical metabolic status in spontaneously fasting birds. Behavior and egg temperature (T(egg)) were continuously monitored by video monitoring and biotelemetry, respectively, in fasting-incubating king penguins kept in a pen to prevent relief by the partner until spontaneous egg abandonment. Penned birds fasted 10 days more and lost 1.2 kg more than birds relieved normally by their partner, abandoning the egg about 1 wk after reaching a critical body mass. Definitive egg abandonment was preceded by transitory abandonments of progressively increasing duration during which time the birds went further and further away from their egg. There were marked interindividual differences but on average transitory abandonments began 36 +/- 5 h before the definitive abandonment and were paralleled by resumption of display songs signaling the readiness of the bird to depart for feeding. T(egg) was maintained at around 35.7 degrees C during normal incubation but significantly decreased the last 2 days before egg abandonment. These changes are interpreted as reflecting a stimulation to refeed at a threshold body mass corresponding to a critical fat store depletion. Thus the fasting-incubating king penguin appears to be an interesting animal model for understanding the long-term metabolic control of feeding behavior in relation to energy status.
本研究旨在了解在自发禁食的鸟类中，当体重低于阈值或处于临界代谢状态时所出现的进食刺激（“再进食信号”）过程。分别通过视频监控和生物遥测技术，对饲养在围栏中的禁食孵卵帝企鹅的行为和蛋温（T(egg)）进行持续监测，以防止其配偶给予救助，直至企鹅自发弃蛋。与能正常得到配偶救助的企鹅相比，被圈养的企鹅多禁食了10天，体重多减轻了1.2千克，在达到临界体重后约1周弃蛋。在最终弃蛋之前，会出现持续时间逐渐增加的短暂弃蛋行为，在此期间，企鹅会离蛋越来越远。个体间存在显著差异，但平均而言，短暂弃蛋行为在最终弃蛋前36±5小时开始，同时伴随着表明企鹅准备外出觅食的展示鸣叫的恢复。在正常孵卵期间，蛋温维持在约35.7摄氏度，但在弃蛋前的最后两天显著下降。这些变化被解释为反映了在对应于临界脂肪储备耗尽的阈值体重时对再进食的刺激。因此，禁食孵卵的帝企鹅似乎是理解与能量状态相关的进食行为的长期代谢控制的一个有趣动物模型。
