1988; Paulini et al., 1987). There is strong evidence of beneficial roles for dietary fiber in the diets of several orders of herbivorous animals (Salley and Bryson, 1957; Cummings et al., 1978; Edwards, 1995), including nonhuman primates, particularly those whose gastrointestinal tracts are specialized for foregut or hindgut fermentation by symbiotic microorganisms (Stevens and Hume, 1995). In fact, the occurrence of morbidity associated with gastrointestinal disease in captive specimens of these specialist primates has been attributed to the low concentrations of fiber in their diets (Gö ltenboth, 1976; Griner, 1977, 1983; Janssen, 1994). The more fermentable (soluble) fraction of dietary fiber may be energetically important for some simple-stomached or hindgut-fermenting nonhuman primates (Cork et al., 1999). Some callitrichid species show evidence of high use of gum arabic included in captive diets, on the basis of measures of dry-matter digestibility (Power and Oftedal, 1996).

Minimal required dietary concentrations of specific kinds of fiber, such as cellulose, or of a broad fiber category, such as NDF, have not been—and perhaps cannot be— established in the same sense as minimal requirements for essential nutrients. However, adverse effects of inappropriate fiber intakes have been reported in nonhuman primates, particularly in species with specialized foregut or hindgut fermentation, and it might be helpful to draw analogies with other well-studied species.

The National Research Council has recommended that the dietary DMof the dairy cow (a foregut fermenter) should contain no more than 30-40% nonstructural carbohydrate to avoid acidosis and other metabolic problems (National Research Council, 2001). Minimum recommended NDF concentrations for dairy cattle of various ages and productive states range from 25-33% of dietary DM(National Research Council, 2001). When expressed as ADF, the recommended minimal range is 17-21%.

The National Research Council has recommended that the horse (a hindgut fermenter) receive sufficient forage to minimize digestive dysfunctions attributable to sudden dietary change and the feeding of excessive concentrate (inadequate fiber) (National Research Council, 1989). Depending on age and activity, recommended proportions of forage in the total dietary dry matter fed to horses range from 30-100%. Corresponding values for dietary NDF or ADF were not provided.

Fiber concentrations in the diets of free-ranging nonhuman primates can serve as guides for fiber in the diets of captive species, and data on fiber concentrations in wild-

Front Matter (R1-R20)

Overview (1-4)

1 Feeding Ecology, Digestive Strategies, and Implications for Feeding Programs in Captivity (5-40)

2 Energy (41-57)

3 Carbohydrates and Fiber (58-74)

4 Protein (75-86)

5 Fats and Fatty Acids (87-93)

6 Minerals (94-112)

7 Vitamins (113-149)

8 Water (150-158)

9 Pathophysiologic and Life-Stage Considerations (159-181)

10 Diet Formulation, Effects of Processing, Factors Affecting Intake, and Dietary Husbandry (182-190)

11 Nutrient Requirements (191-194)

12 Composition of Foods and Feed Ingredients (195-258)

13 Food as a Component of Environmental Enhancement (259-265)

Appendix (266-268)

About the Authors (269-272)

Index (273-286)