Table 12. — Age at death and mortality rate of rats Jed various diets — Continued 





Rats 



Ag 



e at death 







Rats dyin 



g befon 









Strain and diet 



Aver- 

 age 



50 per- 

 cent 

 died 

 by- 



Old- 

 est 

 rat 



400 



days 



500 



days 



600 



days 



700 



days 



800 



days 



900 



days 



1,000 



days 



1,100 

 days 



Wistar rats 



Littermates fed — 



SP 8 HVO 



Num- 

 ber 

 10 

 10 



9 

 9 



Days 

 739 

 654 



703 



424 



Days 

 836 

 742 



755 

 381 



Days 

 876 

 888 



1,028 



762 



Per- 

 cent 

 

 30 



11 



44 



Per- 

 cent 

 10 

 30 



11 

 56 



Per- 

 cent 

 20 

 40 



33 



89 



Per- 

 cent 

 40 

 40 



33 



89 



Per- 

 cent 

 40 

 60 



78 

 100 



Per- 

 cent 

 100 

 100 



78 



Per- 

 cent 



Per- 

 cent 



SPE 







BHE parents fed Wistar stock 

 diet 



Young fed — 



SP 8 HVO 



78 



100 



SPE 













DiET: SP 8 HVO 



DIET: SPE 



% DY 



ING 



30 











20 











v.v.v.v.v.;.y 



- 



SO 











v.v.v.v.v.v 



- 























% DY 











.; v ;.;.;.; v ; v ; v 



- 



~WMM. 



- .- 









- 



Y.Y.Y.Y.«.Y. 



- 









NONE 



yXyXyXyM 1 1 



30 



20 



10 



5 6 



8 



9 > 



7 89><4 56 7 

 AGE (hundred days) 



Figure 4. — Percentage of total number of rats dying within different age intervals on SP 8 HVO and SPE diets. 



Kind and level of fat. — Data available, al- 

 though limited, suggest that the lifespan of rats 

 may be influenced by the kind and/or level of fat 

 in the semipurified diet. When the dietary fat 

 was HVO, the average age at death was approxi- 

 mately the same whether the level of fat was 8 or 

 16 percent. Although there appeared to be no 

 difference between the survival of rats fed diets 



containing S or 16 percent lard, the lifespan of 

 both groups was less than that of animals fed the 

 diets containing HVO. When butter was the 

 dietary fat and the level was 8 percent, the average 

 age at death was close to that observed with 

 HVO but decreased when the diet contained 16 

 percent butter to approximately that observed 

 when lard was the dietary fat. 



24 



