萬萬想不到：竹子並非大熊貓最理想食物？！

The mystery of why giant pandas are forced to spend 14 hours a day eating foods has finally been solved - they can only digest around 17 per cent of the bamboo they swallow.
大熊貓不得不一天14個小時都在進食的謎題近日終於被解開了。它們只能消化大概17%吞食下去的竹子。

Researchers found their gut bacteria are not the type for efficiently breaking down bamboo. In fact they are built to eat meat. The giant panda actually harbours a carnivore-like gut, according to the research published in the journal mBio.
研究人員發現大熊貓體內的那種腸道細菌不能有效降解竹子。實際上它們卻能消化肉食。據《mBio》期刊報導的研究稱，大熊貓其實擁有與肉食者類似的腸道。

Pandas are one of the most endangered species on Earth, with only 1,600 animals left in the wild.
大熊貓是地球上最瀕危的物種之一，野生大熊貓只剩下1600只。

The study's lead author Zhihe Zhang, director of the Chengdu Research Base of Giant Panda Breeding in China, said: "Unlike other plant-eating animals that have successfully evolved, anatomically specialised digestive systems to efficiently deconstruct fibrous plant matter, the giant panda still retains a gastrointestinal tract typical of carnivores.
這個研究的第一作者、中國成都大熊貓繁育基地的主任張志和說：“其他植食性動物已經進化成功，構造上有着專門的消化系統能有效地分解植物纖維，然而大熊貓和這些動物不同，它們仍保留着肉食性動物的消化道。”

"The animals also do not have the genes for plant-digesting enzymes in their own genome. This combined scenario may have increased their risk for extinction."
“大熊貓自身的基因組裏還沒有植物消化酶的基因。這些綜合情況也許會加劇它們滅絕的危機。”

Study co-author Doctor Xiaoyan Pang, an associate professor in the School of Life Sciences and Biotechnology at Shanghai Jiao Tong University, said: "This result is unexpected and quite interesting, because it implies the giant panda's gut microbiota may not have well adapted to its unique diet, and places pandas at an evolutionary dilemma."
這項研究的共同作者、上海交通大學生命科學與技術學院的副教授龐小燕博士指出：“這一研究結果出人意料，而且十分有趣。因爲這表明大熊貓的腸道細菌也許沒能很好地適應大熊貓特殊的飲食，並讓大熊貓陷入進化的困境。”

The researchers said that giant pandas evolved from bears that ate both plants and meat, and started eating bamboo exclusively about two million years ago.
研究人員們稱，大熊貓從雜食性熊進化而來，並在大約兩百萬年前開始專吃竹子。

The animals spend up to 14 hours daily consuming up to 12.5 kilos (27.5 pounds) of bamboo leaves and stems, but can digest only about 17 per cent of it; their faeces is mainly composed of undigested bamboo fragments.
大熊貓每天花上14個小時消耗多達12.5公斤（27.5磅）的竹葉和竹竿，但是隻能消化大概17%。它們的糞便大多由未消化的竹子殘渣組成。

The researchers had been intrigued by how the animals digest bamboo fibre and extract nutrients from it.
研究人員對大熊貓怎麼消化竹子纖維，從中獲取營養物質很感興趣。

The researchers found that despite their diet, the giant pandas, together with nine captive and seven wild individuals investigated previously, showed extremely low gut microbiota diversity and an overall structure that diverged from non-panda plant-eaters but was similar to carnivorous and omnivorous bears.
他們發現儘管它們的飲食如此，這些大熊貓，包括之前被研究的9只圈養大熊貓和7只野生個體，都表現出極低的腸道細菌多樣性。而且它們腸道菌整體的結構不同於其他植食性動物，反而和肉食性和雜食性的熊類似。