The following supplements per animal were fed 

 with all diets: Percomorph oil, 2 drops weekly, 

 supplying 395 I.U. of vitamin A and 56 I.U. of 

 vitamin D daily; <i/-alpha-tocopherol acetate, 36 

 mg. in 0.01 ml. of cottonseed oil weekly, or 5.1 

 mg. daily; fresh kale, 10 grams twice weekly. 



In table 1 are summarized the modifications of 

 this diet and the codes used in the text. Egg, 

 milk, beef, or peanut butter were substituted for 

 part of the semipurified diet in such a way that 

 all of these diets contained approximately the 

 same amount of protein and of fat. The fat con- 

 tent of these diets was approximately twice that 

 present in the semipurified diet. The foods 

 themselves provided the extra fat in SPE or 

 SPPB diets. Extra fat beyond that in the food 

 to be studied was provided by butterfat in the 

 SPM diet and by suet in the SPB diet. The 

 diets containing 8 and 16 percent HVO, lard, or 

 butter were all identical except for the kind and 

 level of fat and the reduced level of sucrose when 

 16 percent fat was used. Other modifications of 

 the SP 8 HVO diet and the diets consisting of 100 

 percent whole egg, 100 percent egg yolk, or 97 

 percent egg yolk with added salt mixture (3 per- 

 cent) were included in an attempt to elucidate the 

 possible role of egg fat or protein, or both in the 

 response of rats to the SPE diet. In addition, 

 the effect of adding certain supplements (selected 

 vitamins and cholesterol) to the SPE diet was 

 investigated to obtain some information on the 

 possibility that an imbalance of nutrients was a 

 factor in the response of rats to this diet. 



To each 100 grams of SPE diet the folio wing- 

 sup plements were added: 

 Choline, 0.5 gram 

 Vitamin B 12 , 0.01 mg. 

 Choline, 0.5 gram+vitamin B 12 , 0.01 mg. 

 Vitamin B 6 , 0.5 mg. 

 Choline, 0.5 gram+vitamin B 6 , 0.5 mg. 

 Choline, 0.5 gram+vitamin B 6 , 0.5 mg.+ 



vitamin B 12 , 0.01 mg. 

 Cholesterol, 0.46 gram 

 Cholesterol, 1.38 grams 

 Ascorbic acid, 0.2 gram 

 Cholesterol, 0.46 gram + ascorbic acid, 0.2 



gram. 



The dry ingredients for the experimental diets 

 were weighed in the proportions already described 

 and placed in a Hobart mixer, with the sucrose 

 added last. The melted fat was poured onto the 

 sucrose, and the diet was prepared by blending 

 in the mixer. This procedure resulted in a more 

 uniform product than that obtained when the fat 

 was added to the mixed dry ingredients. 



Dried whole egg, before being added to the SPE 

 diet, was blended with water, then cooked in a 

 double boiler and stirred constantly until the egg 

 was firm and dry in appearance; the lumps were 

 broken in a Foley mill, dried at 150° F. with forced 

 draught, and ground. 



For the SPB diet, the beef was cut in 4-inch 

 cubes and cooked in water, in a large steam- 



Table 1 . — Diet codes and description 

 of experimental diets 



Code 



SP 8HVO.. 

 SPE 



SPM 



SPB 



SPPB 



SP 16 HVO . 



SP 8 lard... 

 SP 16 lard__ 

 SP 8 butter. 

 SP 16 butter 

 SPa 16 HVO 



SPb 8HVO_._ 



SPEW 



SPEY 



SPW 8HVO-. 



E100 



Y100 



Y97+salt 

 mixture 



Description 



Semipurified. 



SP 8 HVO, 75 percent + whole egg, 



commercially dried, 1 25 percent. 

 SP 8 HVO, 75 percent + skim milk, 2 



15 percent + butterfat, 3 10 percent. 

 SP 8 HVO, 75 percent + beef, 4 15 per- 

 cent + beef suet, 5 10 percent. 



SP 8 HVO, 80 percent + peanut but- 

 ter, 6 20 percent._ 

 SP 8 HVO with HVO level increased to 



16 percent and sucrose decreased to 

 44 percent. 



SP 8 HVO with lard i replacing HVO. 

 SP 16 HVO with lard replacing HVO. 

 SP 8 H VO with butter 3 replacing HVO. 

 SP 16 HVO with butter replacing HVO. 

 SP 16 HVO with casein increased to 20 



percent, lactalbumin increased to 10 



percent, and sucrose decreased to 38 



percent. 

 SP 8 HVO with casein increased to 20 



percent, lactalbumin increased to 10 



percent, and sucrose decreased to 46 



percent. 

 SP 8 HVO, 86 percent, except HVO, 15 



percent; sucrose, 41 percent; and egg 



white, 8 10 percent. 

 SP 8 HVO, 66 percent, except no HVO; 



sucrose, 43 percent; and egg yolk, 8 



30 percent. 

 SP 8 HVO with egg white, 24 percent, 



replacing casein and lactalbumin. 

 Whole commercially dried egg, 100 



percent. 

 Fresh egg yolk, cooked and dried, 100 



percent. 



Y100, 97 percent, + salt mixture, 3 

 percent. 



1 Whole egg, spray dried, from Henningsen Bros., Inc. 



2 Starlac, from Borden Co. 



3 Butter washed free of protein and salt. Animal 

 Husbandry Research Division, Agricultural Research 

 Service, Beltsville, Md. 



4 Beef rounds from dual-purpose cattle with all visible 

 fat removed. Meat Quality Laboratory, Animal Hus- 

 bandry Research Division, Agricultural Research Service, 

 Beltsville, Md. 



5 Beef suet from kidney area. Meat Quality Laboratory, 

 Animal Husbandry Research Division, Agricultural 

 Research Service, Beltsville, Md. 



Peanut butter from two sources: (1) Prepared from 

 roasted white Spanish peanuts by Southern Utilization 

 Research Laboratory in accordance with directions 

 published by the Laboratory (18). The peanut butter 

 contained 1.2 to 1.3 percent commercial hydrogenated 

 peanut oil (Onesta Hardener, Procter and Gamble Co.). 

 (2) Peter Pan Peanut Butter containing salt was used for 

 most of the investigations. 



7 Lard. Animal Husbandry Research Division, Agri- 

 cultural Research Service, Beltsville, Md. 



8 Prepared in the laboratory from hard-boiled eggs. 



jacketed kettle, for 30 minutes. The beef was 

 then ground, dried, and reground to produce a fine 

 powder for blending with other ingredients of the 

 diet. The beef suet was rendered and refrigerated 

 until used. 



