Fietz J, Tataruch F, Dausmann K H, Ganzhorn J U
Dept. of Animal Physiology, Philipps-University, 35032 Marburg, Germany.
J Comp Physiol B. 2003 Feb;173(1):1-10. doi: 10.1007/s00360-002-0300-1. Epub 2002 Nov 7.
In temperate species, hibernation is enhanced by high levels of essential fatty acids in white adipose tissue. Essential fatty acids cannot be synthesized by mammals, thus nutritional ecology should play a key role in physiological adaptations to hibernation. Tropical hibernators are exposed to different physiological demands than hibernators in temperate regions and are expected to be subject to different constraints. The aims of this study were to assess whether or not the tropical hibernator Cheirogaleus medius shows biochemical changes in its white adipose tissue before and during hibernation. A capture-recapture study was combined with feeding observations in western Madagascar. Before and after hibernation, 77 samples of white adipose tissue from 57 individuals of C. medius, as well as dietary items eaten during pre-hibernation fattening, were sampled and analyzed for their fatty acid composition. In contrast to temperate hibernators, C. medius exhibits extremely low essential fatty acid concentrations in its white adipose tissue (2.5%) prior to hibernation. The fatty acid pattern of the white adipose tissue did not change during pre-hibernation fattening and did not reflect dietary fatty acid composition. During hibernation, fat stores showed only minor but significant compositional changes. Because of its prevalence, the main fuel during hibernation was the monounsaturated oleic acid, which seemed to be preferentially synthesized from dietary carbohydrates. Results suggest that essential fatty acids do not represent an ecological limitation for hibernation in the tropics, at least not in the fat-tailed dwarf lemur.
在温带物种中，白色脂肪组织中高水平的必需脂肪酸会增强冬眠能力。哺乳动物无法合成必需脂肪酸，因此营养生态学在对冬眠的生理适应中应发挥关键作用。与温带地区的冬眠动物相比，热带冬眠动物面临不同的生理需求，预计会受到不同的限制。本研究的目的是评估热带冬眠动物肥尾侏儒狐猴在冬眠前和冬眠期间其白色脂肪组织是否会出现生化变化。在马达加斯加西部，将标记重捕研究与觅食观察相结合。在冬眠前后，采集了57只肥尾侏儒狐猴的77份白色脂肪组织样本，以及冬眠前育肥期间食用的食物，并分析了它们的脂肪酸组成。与温带冬眠动物不同，肥尾侏儒狐猴在冬眠前其白色脂肪组织中的必需脂肪酸浓度极低（2.5%）。白色脂肪组织的脂肪酸模式在冬眠前育肥期间没有变化，也没有反映出饮食中的脂肪酸组成。在冬眠期间，脂肪储备仅出现了微小但显著的成分变化。由于其普遍性，冬眠期间的主要燃料是单不饱和油酸，它似乎优先由饮食中的碳水化合物合成。结果表明，必需脂肪酸对热带地区的冬眠来说并非生态限制因素，至少对肥尾侏儒狐猴而言不是。
