MINERAL CONCENTRATIONS IN WHOLE MICE AND RATS USED AS FOOD

Calcium (Ca), magnesium (Mg), copper (Cu), iron (Fe), manganese (Mn), and zinc (Zn) concentrations were measured in whole mice (five sizes) and rats (six sizes). Ca concentrations increased with age in both mic e (1.2-2.3%) and rats (1.9-3.3%). Mg levels ranged from 0.09 to 0.13% (mice) and from 0.11 to 0.18% (rats), with the medium-size class of bo th species having the highest values. Cu (7.9-19.2 and 10.8-60.6 mg/kg ) and Zn (58.0-82.5 and 73.2-113.6 mg/kg) generally decreased with age in both species, while Mn levels tended to increase with age (0.2-13. 1 mg/kg, mice; 6.2-28.3 mg/kg, rats). Fe values were highest in neonat es and adult size classes, ranging from 113.4 to 181.3 mg/kg (mice) an d 111.3 to 332.6 mg/kg (rats). Rats usually contained higher concentra tions of individual minerals than equivalent age categories of mice, e ven though both were fed identical diets. All rodents analyzed general ly met known dietary requirements of mammalian carnivores, but differe nces between mice and rats were apparent. Specific mineral nutrient re quirements for carnivorous birds and reptiles have not been determined . (C) 1996 Wiley-Liss, Inc.