Bozinovic, F.: Nutritional Energetics and Digestive Responses of an Herbivorous Rodent (Octodon degus) to Different Levels of Dietary Fiber

Francisco Bozinovic: Nutritional Energetics and Digestive Responses of an Herbivorous Rodent (Octodon degus) to Different Levels of Dietary Fiber.
In: Journal of Mammalogy Vol. 76, No. 2 (May, 1995), pp. 627-637.

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Zitat :

Abstract

Complex polysaccharides such as cellulose, hemicellulose, and lignin (fiber) are important structural constituents of plants that often are difficult for small herbivorous mammals to digest. These polysaccharides may affect the efficiency with which food is digested and with which nutrients and energy are transformed and allocated. To determine how small herbivorous mammals cope with such high-fiber food, I used as a model the herbivorous, caviomorph octodontid rodent Octodon degus, the degu, an inhabitant of the semiarid and Mediterranean environments of northern and central Chile. When given a choice, degus minimized fiber intake, showing pronounced preferences for food containing low fiber. Because low-fiber items are not available in the field during the dry season, I postulated that observations of degus feeding on grass containing a high percentage (nearly 60%) of fiber during summer are more likely the consequence of necessity than of choice. I suggested that during nutritional bottlenecks, degus operate according to the principles of foraging theory and principles governing digestion. Degus seemed to compensate for the low digestibility of high-fiber food by increasing the volume of digesta in the alimentary canal as a consequence of changes in rates of food intake and, hence, increases in turnover time of digesta. The digestive responses allowed them to increase the amount of energy obtained from fiber and to satisfy their maintenance energy costs during temporal exposures to different levels of food fiber.