HOW DO FOOD PASSAGE RATE AND ASSIMILATION DIFFER BETWEEN HERBIVOROUS LIZARDS AND NONRUMINANT MAMMALS
HOW DO FOOD PASSAGE RATE AND ASSIMILATION DIFFER BETWEEN HERBIVOROUS LIZARDS AND NONRUMINANT MAMMALS
复制标题
DOI：
10.1007/bf00691047
复制
发表时间：
1986-01-01
影响因子：
2
通讯作者：
DIAMOND, JM
中科院分区：
文献类型：
--
作者：
KARASOV, WH;PETROSSIAN, E;DIAMOND, JM
尽管在消化解剖学和生理学上大体相似，但什么样的消化适应能使食草性非反刍类哺乳动物保持比食草性蜥蜴高得多的代谢率？我们通过比较两种蜥蜴(Chuckwalla和沙漠鬣蜥)和两种哺乳动物(沙漠林鼠和实验室老鼠)对吃相同食物的紫花苜蓿颗粒的食草性物种来解决这个问题。哺乳动物的小肠和大肠更长，肠道表面积更大，按代谢活体质量标准的食物摄入量要高得多(按一个数量级)，食物通过时间也快得多(几个小时而不是几天)。在爬行动物和哺乳动物中，通过时间都随着身体的大小而增加，食草动物的通过时间比肉食动物的长。食草性蜥蜴尽管通过时间要慢得多，但其表观消化效率略低于哺乳动物。至少对于Chuckwallas来说，这种与哺乳动物的不同并不是由于体温的不同。通过比较两种动物对不同食物成分的同化作用，发现S的主要优势在于对膳食纤维组分的同化程度较高。虽然停留时间较短，但两种动物对纤维的消化率较高，这可能是因为它们的发酵室较大、吞噬能力较强和/或微生物发酵条件不同所致。最后，我们对食草性蜥蜴和哺乳动物的消化功能进行了比较概述，并列出了四个尚未解决的主要问题。
What digestive adaptations permit herbivorous nonruminant mammals to sustain much higher metabolic rates than herbivorous lizards, despite gross similarity in digestive anatomy and physiology? We approached this question by comparing for herbivorous species eating the same diet of alfalfa pellets: two lizards (chuckwalla and desert iguana) and two mammals (desert woodrat and laboratory mouse). The mammals had longer small and large intestines, greater intestinal surface area, much higher (by an order of magnitude) food intake normalized to metabolic live mass, and much faster food passage times (a few hours instead of a few days). Among both reptles and mammals, passage times increase with body size and are longer for herbivores than for carnivores. The herbivorous lizards, despite these much slower passage times, had slightly lower apparent digestive efficiencies than the mammals. At least for chuckwallas, this difference from mammals was not due to differences in body temperature regime. Comparisons of chuckwallas and woodrats in their assimilaton of various dietary components showed that the woodrat''s main advantage lay in greater assimilation of the dietary fiber fraction. Woodrats achieved greater fiber digestion despite shorter residence time, but possibly because of a larger fermentation chamber, coprophagy, and/or different conditions for microbial fermentation. We conclude with a comparative overview of digestive function in herbivorous lizards and mammals, and with a list of four major unsolved questions.