van der Ziel C E, Visser G H
Zoological Laboratory, P.O. Box 14, 9750 AA Haren, The Netherlands.
Physiol Biochem Zool. 2001 Jan-Feb;74(1):52-65. doi: 10.1086/319314.
To investigate whether there is a relationship between the inherent maximum growth rate of a chick and its degree of developmental plasticity, we studied the effects of food restriction on morphological and physiological development in P-line (selected for high growth rates) and C-line (nonselected) chicks of the Japanese quail between 2 and 64 d of age. In each line, three groups were created; one group in which the chicks were fed ad lib. and two other groups in which the chicks received 70% and 40% of the line-specific ad lib. feeding levels, respectively. In all three groups, chick survival rates were very high, and no relationship was detected between feeding level and chick mortality. The experimental feeding levels strongly affected the chicks' attainment of body mass at all ages. In addition, at most ages the growth of the structural components (wing, tarsus, and head) were also significantly affected by the feeding experiment but to a much smaller extent than the body mass. The feeding levels also affected the achievement of female sexual maturity such that, at the end of the experiment, most of the ad lib.-fed females and none of the females that received 40% of the ad lib. feeding level were laying eggs. In chicks of both lines that were fed ad lib., homeothermy was achieved at 7 d of age, but in chicks that received 40% of the line-specific ad lib. levels, homeothermy was achieved after 15-22 d of age. Poikilothermic chicks (P- and C-line) that were relatively heavy for their age exhibited relatively high resting metabolic rates (RMRs) and peak metabolic rates (PMRs) for their age. In addition, a positive relationship was found between the chicks' relative mass and RMR (based on mass-based predictive equations). No relationship was detected between the chicks' relative body mass and their relative PMR (relative to mass-based predictive equations). With respect to the metabolic scope (i.e., PMR-RMR), Japanese quail chicks exhibited remarkable developmental plasticity: chicks with body masses that were 50% lower than the normal growing chicks did exhibit a normal capacity of thermogenic heat production for their mass. Because no differences were found with respect to the level of plasticity of morphological and physiological development between the two strains, we conclude that the selection for high postnatal growth rates in P-strain chicks has not resulted in a in a higher vulnerability of these chicks to food restrictions.
为了研究雏鸡的固有最大生长速率与其发育可塑性程度之间是否存在关联，我们研究了食物限制对日本鹌鹑P系（选择高生长速率）和C系（未选择）雏鸡在2至64日龄期间形态和生理发育的影响。在每个品系中，创建了三组；一组雏鸡自由采食，另外两组雏鸡分别获得品系特定自由采食水平的70%和40%。在所有三组中，雏鸡存活率都非常高，未检测到采食水平与雏鸡死亡率之间的关系。实验采食水平在所有年龄段都强烈影响雏鸡的体重增长。此外，在大多数年龄段，结构组成部分（翅膀、跗骨和头部）的生长也受到采食实验的显著影响，但程度远小于体重。采食水平还影响雌性性成熟的达成，以至于在实验结束时，大多数自由采食的雌性已产蛋，而采食水平为自由采食水平40%的雌性均未产蛋。在两个品系自由采食的雏鸡中，7日龄时实现了体温调节，但在采食水平为品系特定自由采食水平40%的雏鸡中，15至22日龄后才实现体温调节。相对于年龄而言体重较重的变温雏鸡（P系和C系）表现出相对较高的静息代谢率（RMR）和峰值代谢率（PMR）。此外，在雏鸡的相对体重与RMR之间发现了正相关关系（基于基于体重的预测方程）。未检测到雏鸡的相对体重与其相对PMR之间的关系（相对于基于体重的预测方程）。关于代谢范围（即PMR - RMR），日本鹌鹑雏鸡表现出显著的发育可塑性：体重比正常生长雏鸡低50%的雏鸡确实表现出与其体重相称的正常产热能力。由于在两个品系之间未发现形态和生理发育可塑性水平的差异，我们得出结论，对P系雏鸡出生后高生长速率的选择并未导致这些雏鸡对食物限制更易受影响。
