Thesis
Nutritional wisdom of bears: macronutrient selection and metabolism
Washington State University
Master of Science (MS), Washington State University
2013
Handle:
https://hdl.handle.net/2376/105152
Abstract
Many animals consume mixed diets that maximize their fitness by optimizing macronutrient intake. We tested whether grizzly bears (Ursus arctos horribilis), a generalist omnivore that hibernates, (i) regulated their diet to a common nutrient target, (ii) achieved a nutrient target related to fitness, and (iii) selected a nutrient target that differed between seasons and from other species with differing life histories. When given unlimited access to two or three highly digestible foods, one of which always contained primarily protein (lean salmon or beef) and others that contained primarily lipid (salmon oil or beef and pork fat) or digestible carbohydrates (bread or apples), grizzly bears selected diets in which protein provided 17 ± 4% of the metabolizable energy and 22 ± 6% of the dry matter. This dietary protein content maximized the rate of gain per unit of energy consumed, is similar to the level preferred by other omnivores, but is less than that preferred by carnivores. Bears strongly preferred lipids over carbohydrates, but they used lipids and carbohydrates with equal efficiency to dilute dietary protein content to a level that maximized mass gain per unit of energy intake. Thus, dietary sources of lipids and carbohydrates play an extraordinarily important role in determining the productivity of bears that goes beyond simply their role in providing energy.
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Details
- Title
- Nutritional wisdom of bears
- Creators
- Joy A. Erlenbach
- Contributors
- Charles T. Robbins (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Biological Sciences, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525301001842
- Language
- English
- Resource Type
- Thesis