Biology Faculty & Staff Publications

Document Type

Article

Publication Date

2-1-1992

Abstract

Allometric considerations have suggested that small herbivores are inefficient at or incapable of extracting energy from the microbial fermentation of structural carbohydrates. This notion is at odds with accumulating empirical evidence that demonstrates well-developed fiber digestion abilities for a number of small rodent genera. To examine the apparent inconsistency, we have constructed a model of plant fiber utilization tailored specifically for hindgut fermenters. Computer simulations provide estimates of fiber and overall dry-matter digestibilities as a function of body size, energy demand, and diet. Our calculations indicate that small mammals can obtain significant benefit from fiber fermentation, especially at moderate fiber levels. Comparisons with literature data are in general agreement, although fiber digestion abilities are still underestimated for the smallest animals. In an empirical test of the model, Neotoma obtained over 21 % of their digestible energy solely from the microbial fermentation of plant fiber. We also observed an interesting pattern of allometric sorting predicted by the model. Smaller wood rats significantly reduced the fiber content of their diet, a behavior presumably reflecting energy limitations.

Publisher

The University of Chicago Press

ISSN

0003-0147

Volume

139

First Page

398

Last Page

416

Language (ISO)

English

Keywords

dietary fiber, Neotoma, fermentation

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