ABSTRACT
In 1957 J. P. Greenstein et al., reported the development of a water-soluble, chemically defined diet (CD diet) for CV rats. The development of the CD diets started because of practical necessity, especially for the production of germfree (GF) mice. In 1992 the GF-CD BALB/c colony was in its tenth generation. Growth is comparable to that seen with natural ingredient diet L-485.20 There is a consistent 20% reduction in litter size compared with CV animals fed diet L-485 — so consistent that it may point to a physiological factor rather than a mild dietary deficiency. When resting oxygen consumption and heart size were determined earlier in GF-CD C3H mice, values were 38 and 27% higher, respectively, than in GF mice maintained on solid diet L-485. This suggests that GF mice fed an amino acid diet require additional energy to utilize this major diet component.
