FACTORS ALTERING XTTTRITIONAL VALT'E 917 



effective in ensuring normal pregnancy and lactation. Data illustrating 

 this are given in Tal)le 8. 



Table 8 



The Comparative Nutritional Value, as Determined by 



Performance in Pregnancy and Lactation, in Rats 



Receiving Diets Containing Butterfat 



OR Various Vegetable Oils" 



" Adapted from H. J. Deuel, Jr., E. Movitt, and L. F. Hallman, J. Nutrition, 27, 509- 

 513(1944). 



'' Figures in parentheses indicate the numlier of rats weaned. Only seven-rat litters 

 are included in the average. 



Euler, Euler, and Ronnestam-Saberg'^^ carried out a very extensive two- 

 year studj^ of the reproductive performance of rats on diets containing but- 

 ter or margarine without and with added vitamin E. The total weight of 

 the offspring at the age of thirty days, which gives an index of the number 

 of young and the effectiveness of the lactation, over a period of one and a 

 half years, was 8,508 g. for the group on the butter-containing diet, as com- 

 pared with the figure of 15,955 g. for those on the margarine fat regimen. 

 Although supplementation with vitamin E improved the performance of 

 the butterfat group, the total weight of such litters was still less satisfactory 

 than was that of the unsupplemented margarine group. Euler and Euler'^^ 

 reported later that, for a period of eighteen months, covering four genera- 

 tions, butter and margarine, when fed in a diet consisting of 24% skim milk 

 powder, 10% fat, 65% wheat powder, 1% sodium chloride, o g. of spinach, 

 and 5 g. of meat per animal per week, together with 100 I.U. of vitamin A 

 and 5.8 I.U. of vitamin D, resulted in no significant differences in longevity 

 and fertility or in growth rate. In view of these results, and especially 



3« B. v. Euler and H. v. Euler, Arkiv. Kemi, 3, 31-39 (1951 ). 



