Data from: Novel energy-saving strategies to multiple stressors in birds: the ultradian regulation of body temperature

This study aimed to examine thermoregulatory responses in birds facing two commonly experienced stressors, cold and fasting. Logging devices allowing long-term and precise access to internal body temperature were placed within the gizzards of ducklings acclimated to cold (CA) (5°C) or thermoneutrality (TN) (25°C). The animals were then examined under three equal 4-day periods: ad libitum feeding, fasting and re-feeding. Through the analysis of daily as well as short-term, or ultradian, variations of body temperature, we showed that while ducklings at TN show only a modest decline in daily thermoregulatory parameters when fasted, they exhibit reduced surface temperatures from key sites of vascular heat exchange during fasting. The CA birds, on the other hand, significantly reduced their short-term variations of body temperature while increasing long-term variability when fasting. This phenomenon would allow the CA birds to reduce the energetic cost of body temperature maintenance under fasting. By analysing ultradian regulation of body temperature, we describe a means by which an endotherm appears to lower thermoregulatory costs in response to the combined stressors of cold and fasting.

本研究旨在探究鸟类遭遇冷暴露与禁食这两种常见应激原时的体温调节响应。将可实现长期精准采集体内体温的记录装置，植入适应低温（cold acclimated, CA，5℃）或热中性环境（thermoneutrality, TN，25℃）的雏鸭肌胃内。随后将实验动物分为三个均等的4天周期开展观测：自由采食、禁食及复饲阶段。通过分析体温的每日及短期（超日节律，ultradian）波动，我们发现：处于热中性环境的雏鸭在禁食时仅表现出体温调节参数的小幅下降，但其核心血管换热关键位点的体表温度会出现降低。与之相对，低温适应组雏鸭在禁食期间，其体温的短期波动显著降低，但长期波动却有所升高。该现象可使低温适应组个体在禁食状态下降低体温维持的能量成本。通过分析体温的超日节律调控机制，我们揭示了内温动物（endotherm）应对冷暴露与禁食联合应激时，降低体温调节成本的一种潜在途径。