Contents 



Page 



Experimental 1 



Description and management of animals 1 



Diets - 2 



Criteria for evaluating response to diet 4 



Results and discussion 5 



Composition of experimental diets 5 



Protein 5 



Fat 5 



Vitamins 9 



Minerals 9 



Calories 9 



Body weight and longevity as influenced by 



diet 11 



Body weight, intake, and age (stock, SP 



8 HVO, and SPE diets) 11 



Growth and food intake of young rats (all 



diets) 14 



Body weight in relation to age and diet in 



adult rats 18 



Calories for maintenance of body weight.. 20 



Maximum body weight and diet 20 



Page 

 Results and discussion — Continued 



Body weight and longevity as influenced by 

 diet — Continued 



Longevity 22 



Summary 29 



Histology and size of selected organs 29 



Histology of kidney 29 



Histology of liver 36 



Kidney and liver weight 37 



Adrenal weight 52 



Thyroid weight 57 



Thymus weight 62 



Chemical investigations 62 



Kidney 62 



Urinary protein 66 



Liver 68 



Serum cholesterol 78 



Serum protein components 86 



General summary and implications for future re- 

 search 91 



Literature cited 93 



Appendix i 101 



Tables 



Experimental Diets 



Page 



1. Diet codes and description of experimental 13. 



diets 3 



2. Protein and amino acid content per 100 grams 



of diet, and suggested requirements for the 



rat 6 



3. Fatty acid content per 100 grams of diet and 



iodine value of dietary fat 7 



4. Fat, fatty acid, and cholesterol content per 100 



grams of diet 8 



5. Vitamin content of diets, and suggested require- 



ments for the rat 10 



6. Ash and mineral content per 100 grams of diet, 



and suggested requirements for the rat 11 



7. Calorie values per 100 grams of diet, and per- 



centage of calories as carbohydrate, fat, and 

 protein 11 



Body Weight 



8. Growth, food intake, and calories per gram of 



gain in young rats fed various diets 16 



9. Body weight of rats at different ages fed various 



diets 19 



10. Calories per gram of body weight per week for 



maintenance of adult rats fed various diets. _ 20 



11. Maximum weight of rats fed various diets, sac- 



rificed before or after 500 days of age 21 



12. Age at death and mortality rate of rats fed 



various diets 23 



14. 



15. 



16. 



17. 



18. 



19. 



20. 



21. 



Body Weight— Continued 



Maximum age of rats before weight loss in 

 relation to caloric intake during the first 

 300 days on SP 8 HVO and SPE diets 



Histology 



Kidney damage determined microscopically 

 for rats maintaining weight at different ages 

 on stock, SP 8 HVO, and SPE diets 



Kidney damage determined microscopically 

 for rats losing weight at different ages on 

 stock, SP 8 HVO, and SPE diets 



Calcium determined microscopically in kidneys 

 of fasted and nonfasted rats losing weight 

 at different ages on SPE diet 



Kidney damage determined microscopically for 

 rats maintaining or losing weight at different 

 ages on SPM, SPB, and SPPB diets 



Kidney damage determined microscopically for 

 rats fed all other diets 



Liver fat determined microscopically for fasted 

 and nonfasted rats maintaining or losing 

 weight at different ages on SPE diet 



Liver fat determined microscopically for rats 

 fed SPM, SPB, and SPPB diets 



Liver fat determined microscopically for rats 

 fed other experimental diets 



Page 



27 



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36 



37 

 38 



iii 



