动物生理学. 食竹的大熊猫极低的日能量消耗。

ANIMAL PHYSIOLOGY. Exceptionally low daily energy expenditure in the bamboo-eating giant panda.

机构信息

Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.

State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China. Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, Scotland, UK.

出版信息

Science. 2015 Jul 10;349(6244):171-4. doi: 10.1126/science.aab2413.

DOI:10.1126/science.aab2413

PMID:26160943

Abstract

The carnivoran giant panda has a specialized bamboo diet, to which its alimentary tract is poorly adapted. Measurements of daily energy expenditure across five captive and three wild pandas averaged 5.2 megajoules (MJ)/day, only 37.7% of the predicted value (13.8 MJ/day). For the wild pandas, the mean was 6.2 MJ/day, or 45% of the mammalian expectation. Pandas achieve this exceptionally low expenditure in part by reduced sizes of several vital organs and low physical activity. In addition, circulating levels of thyroid hormones thyroxine (T4) and triiodothyronine (T3) averaged 46.9 and 64%, respectively, of the levels expected for a eutherian mammal of comparable size. A giant panda-unique mutation in the DUOX2 gene, critical for thyroid hormone synthesis, might explain these low thyroid hormone levels. A combination of morphological, behavioral, physiological, and genetic adaptations, leading to low energy expenditure, likely enables giant pandas to survive on a bamboo diet.

摘要

肉食性大熊猫以竹子为主要食物，但它的消化道并不能很好地适应这种食物。对 5 只圈养和 3 只野生大熊猫的每日能量消耗进行测量，平均每天为 5.2 兆焦耳（MJ），仅为预测值（13.8 MJ/天）的 37.7%。对于野生大熊猫来说，平均值为 6.2 MJ/天，或哺乳动物预期值的 45%。大熊猫通过减少几个重要器官的体积和降低身体活动来实现这种极低的能量消耗。此外，循环中的甲状腺激素甲状腺素（T4）和三碘甲状腺原氨酸（T3）的水平分别为预期可比体型真兽类水平的 46.9%和 64%。DUOX2 基因的一个大熊猫特有的突变，对甲状腺激素的合成至关重要，可能解释了这些低甲状腺激素水平。形态、行为、生理和遗传适应的结合导致能量消耗降低，这可能使大熊猫能够以竹子为食生存。