研究揭示为什么大熊猫爱吃竹子

A study has shed new light on how bamboo, a highly fibrous plant, provides energy for giant pandas, which have a digestive tract similar to carnivores.
一项研究揭示了竹子这种高度纤维状植物，是如何为大熊猫这种消化道与食肉动物相似的动物提供能量的。

Researchers performed a large-scale metagenome sequencing study of the gut microbiota of giant pandas, which feed almost exclusively on bamboo.
研究人员对大熊猫肠道微生物群进行了大规模的宏基因组研究，这些大熊猫几乎完全以竹子为食。

They found that their gut microbiota does not significantly contribute to the degradation of cellulose and lignin, which are abundant in bamboo.
他们发现，它们的肠道微生物群对富含在竹子内的纤维素和木质素的降解没有显著的作用。

The finding suggests that the animals do not depend on cellulose or lignin to obtain energy.
这一发现表明，这种动物并不依赖纤维素或木质素来获得能量。

Instead, they rely on starch and hemicelluloses in the plant for energy, researchers said.
研究人员称，相反，他们依靠植物中的淀粉和半纤维素来获取能量。

Giant pandas have a higher capability of digesting starch than strict carnivores. They develop increasing abilities to digest starch following the dietary transition from breast milk to bamboo, according to the study.
大熊猫比严格意义上的食肉动物有着更强大的消化淀粉的能力。根据这项研究，大熊猫完成从母乳到竹子的饮食方式转变后，便逐步发展其消化淀粉的能力。

The animals have much higher digestibility for hemicellulose than cellulose, and they prefer bamboo shoots, tender leaves and first-year bamboo, with an abundance of hemicelluloses.
这种动物对半纤维素的消化率远高于纤维素，它们更喜欢竹笋、嫩叶和一年生竹这些半纤维素含量丰富的植物。

"Giant pandas love bamboo partly because it is everywhere in their habitats, and they have few competitors for the food," said Zhang Wenping, who is the first author of the research paper. "In addition, bamboo has high levels of starch among all woody plants."
该研究报告的第一作者张文平表示：“大熊猫喜欢竹子，部分原因是竹子在它们的栖息地到处都是，而且它们几乎没有吃这种食物的竞争对手。除此之外，在所有木本植物中，竹子的淀粉含量也相对较高。”