54-0 APPENDIX 



diets commercially available and specified as complete are at best subsistence formulas. 

 Although analysis of diets may indicate a complete array of ingredients in terms of 

 vitamins, amino acids, and other important constituents, the source material may be 

 deficient quantitatively. Also, even if chemical analysis indicates quantitative suffici- 

 ency of a certain item, subsequent biologic testing may indicate it is unavailable to the 

 test animal in the form applied. Therefore commercial diets should be evaluated 

 critically for the source of ingredients as well as their chemical composition. It is 

 always advisable to examine carefully any data presented by a manufacturer as evidence 

 for a given formulation being better than any other. The individual using mice in his 

 experiments should also demand that the composition of the diet for his animals be 

 known. Arguments are presented against this by commercial manufacturers, including 

 the statement that standardization by chemical analysis is more important than stan- 

 dardization of the source of components. This argument would be valid if more definite 

 information were known concerning the nutritional requirements of the mouse, but 

 unfortunately this type of information is incomplete. Most of the information available 

 indicates that the source of the biochemical is more important, and it is therefore more 

 justifiable to demand a constant-ingredient formulation for mouse diets. 



A good type of diet for mice has been suggested by Morris. 897 • 898 The constituents 

 are as follows : 



With this as a basic formulation, various modifications may be made to suit re- 

 quirements of certain inbred mouse strains. Certain strains are inclined toward 

 obesity and therefore an increased amount of protein and a lowered amount of fat is 

 indicated. This is achieved by increasing or decreasing the amounts of the major 

 sources of protein and fat. 



The feeding of mice should be directed toward meeting the physiologic demands 

 of the specific inbred strain being used, but much work needs to be done in order to 

 delineate appropriate parameters so that the exact nutritional requirements are known. 

 Enough is known of the role nutrition plays in resistance or susceptibility to gamma 



