Department of Biological Sciences, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, Canada, V5A 1S6.
J Exp Biol. 2010 Jun 15;213(Pt 12):1991-2000. doi: 10.1242/jeb.036319.
Recent studies have shown that the metabolic cost of avian egg production involves a 16-27% increase in metabolic rate (MR) above non-reproductive basal or resting values (BMR and RMR, respectively). To determine how the metabolic cost of egg production interacted with the costs of other essential processes (such as cold acclimation and active heat production), we measured the MR of non-breeding and egg-producing zebra finches (Taeniopygia guttata) while (a) warm-acclimated (to 19-21 degrees C) and measured within their thermoneutral zone (at 35 degrees C), (b) cold-acclimated (to 7 degrees C) and measured at thermoneutrality (at 35 degrees C, i.e. not actively producing heat), and (c) cold-acclimated and measured below thermoneutrality (at 7 degrees C) (i.e. during active heat production). The metabolic cost of egg production was small (24% above BMR) compared with the additive costs of cold acclimation and active heat production (224% above BMR). Exposure to low ambient temperatures was accompanied by an increase in seed consumption (by 72%) and a decrease in locomotor activity (by 72%) compared with warm-acclimated, non-breeding values. By contrast, egg production in heat-producing females was associated with an 11% decrease in MR and a 22% decrease in seed consumption compared with non-breeding thermoregulating values. Our data suggest that while the increase in MR associated with egg production is small in relation to the birds' capacity to increase MR in response to other energetically demanding processes, the addition of egg production to these metabolically costly activities may be enough to necessitate the use of energy-saving strategies, such as internal energy reallocation, to cope with the additional energetic demands.
最近的研究表明，鸟类产卵的代谢成本涉及代谢率（MR）比非生殖基础或静息值（BMR 和 RMR）高出 16-27%。为了确定产卵的代谢成本如何与其他基本过程（如冷适应和主动产热）的成本相互作用，我们测量了非繁殖和产卵的斑马雀（Taeniopygia guttata）的 MR，同时（a）在温暖适应（19-21 摄氏度）并在其热中性区（35 摄氏度）内测量，（b）在冷适应（7 摄氏度）并在热中性时测量（35 摄氏度，即不主动产热），和（c）在冷适应和低于热中性时测量（7 摄氏度）（即在主动产热时）。与冷适应和主动产热的附加成本（BMR 以上 224%）相比，产卵的代谢成本很小（BMR 以上 24%）。与温暖适应、非繁殖值相比，暴露于低环境温度会导致种子消耗增加（增加 72%）和运动活动减少（减少 72%）。相比之下，在产生热量的雌性中产卵与 MR 降低 11%和种子消耗降低 22%相关，与非繁殖调节值相比。我们的数据表明，虽然与鸟类增加 MR 以应对其他能量需求过程的能力相比，与产卵相关的 MR 增加幅度较小，但将产卵添加到这些代谢成本高昂的活动中可能足以需要使用节能策略，例如内部能量重新分配，以应对额外的能量需求。
