EFFECTS OF DIET ON NUTRITIONAL CONTENT OF WHOLE VERTEBRATE PREY

Proximate composition (moisture, lipid, protein, ash), vitamin A and v itamin E content, and six minerals (Cu, Fe, Zn, Mg, Mn, Ca) were measu red in quail, rats, mice, and guinea pigs raised on at least two diffe rent diets per species. Feed composition varied substantially but erra tically in lipid, vitamin A, vitamin E, and mineral content. All unsup plemented feeds had less vitamin E than NRC recommendations and most f eeds contained less Mn than recommended. Most feeds deviated from the manufacturer's guaranteed analysis. There were significant effects of diet on body mass, moisture, lipid, ash, vitamin A, vitamin E, Ca, and Cu content for quail. There was a significant effect of diet on vitam in A content of mice; there were no other effects of diet on mammalian species. There was no correlation between diet composition and body c omposition for any species. Rats and mice differed significantly in vi tamin A, Fe, and Cu content when raised on the same diet. We suggest t hat (1) it is difficult to assume or assess composition or adequacy of commercial diets without laboratory analysis, (2) supplementation of diets with whole foods can potentially reduce diet quality, (3) nutrie nt differences in quail are related to differences in growth, and such age-related differences may be more important in determining nutrient content than diet, (4) there were significant species differences in responsiveness to changes in diet, and (5) whole domesticated prey are a potentially inadequate source of vitamin E for raptors and of Mn an d Cu for all carnivores. (C) 1996 Wiley-Liss, Inc.