Hervant Frédéric, Renault David
Hydrobiologie et Ecologie Souterraines, UMR CNRS 5023, 6 rue Dubois, Université Claude Bernard-Lyon I, F-69622 Villeurbanne Cedex, France.
J Exp Biol. 2002 Jul;205(Pt 14):2079-87. doi: 10.1242/jeb.205.14.2079.
The effects of long-term fasting and subsequent refeeding on digestive physiology and energy metabolism were investigated in a subterranean aquatic crustacean, Stenasellus virei, and in a morphologically similar surface-dwelling species, Asellus aquaticus. Metabolic response to food deprivation was monophasic in A. aquaticus, with an immediate, large decrease in all energy reserves. In contrast, S. virei displayed three successive periods of phosphageno-glucidic, lipidic and, finally, proteo-lipidic-dominant catabolism over the course of the nutritional stress. To represent the responses of subterranean crustaceans to food stress and renutrition, a sequential energy strategy was hypothesized, suggesting that four successive phases (called stress, transition, adaptation and recovery) can be distinguished. Based on these results, a general adaptive strategy for groundwater organisms was proposed. Their remarkable resistance to long-term fasting may be partly explained by (1) a depressed metabolism, during which they mainly subsist on lipid stores, (2) a prolonged state of glycogen- and protein-sparing, (3) low energetic requirements and (4) large body stores. In addition, these groundwater species displayed high recovery abilities during refeeding, showing an optimal utilization of available food and a rapid restoration of their body reserves. These adaptive responses might be considered for numerous subterranean organisms as an efficient energy-saving strategy in a harsh and unpredictable environment where fasting (and/or hypoxic) periods of variable duration alternate with sporadic feeding events (and/or normoxic periods). Therefore, food-limited and/or hypoxia-tolerant groundwater species appear to be good examples of animals representing a low-energy system.
研究了长期禁食及随后再投喂对地下水生甲壳动物维氏窄腹钩虾（Stenasellus virei）和形态相似的地表栖息物种普通等足虫（Asellus aquaticus）消化生理和能量代谢的影响。普通等足虫对食物剥夺的代谢反应是单相的，所有能量储备立即大幅下降。相比之下，在营养应激过程中，维氏窄腹钩虾表现出三个连续阶段的磷酸原 - 糖代谢、脂质代谢，最后是以蛋白质 - 脂质为主的分解代谢。为了描述地下甲壳动物对食物应激和再营养的反应，提出了一种顺序能量策略，表明可以区分四个连续阶段（称为应激、过渡、适应和恢复）。基于这些结果，提出了地下水生物的一般适应策略。它们对长期禁食的显著抗性可能部分归因于：（1）代谢降低，在此期间它们主要依靠脂质储备生存；（2）糖原和蛋白质节省的延长状态；（3）低能量需求；（4）大量的身体储备。此外，这些地下水物种在再投喂期间表现出很高的恢复能力，能最佳利用可用食物并迅速恢复其身体储备。在一个禁食（和/或缺氧）期持续时间不定与零星进食事件（和/或常氧期）交替出现的恶劣且不可预测的环境中，这些适应反应可能被视为许多地下生物的一种有效的节能策略。因此，食物受限和/或耐缺氧的地下水物种似乎是代表低能量系统的动物的良好例子。
