850 



XIV. NUTRITIONAL VALUE OF FATS 



duced to the same specific gravity at the start of tests by adding a sufficient 

 number of weights to their bodies. The average swimming period in 

 three series of tests on rats receiving diets containing several proportions 

 of cottonseed oil were as follows: 0%, 654 seconds; 0% but containing 

 1% of linoleate, 636 seconds; 5%, 863 seconds; 10%, 849 seconds; 14% 

 (stock diet), 1021 seconds; 20%, 1043 seconds; and 40%, 1044 seconds. 

 The results were similar, irrespective of whether cottonseed oil or a vege- 

 table margarine fat served as a source of fat in their diets. i- Confirmatory 

 evidence of the increased physical capacity of rats as related to the diets 

 can be deduced from the work of Samuels and collaborators,^^ who used 

 an entirely different method of approach. Tests were made on the amount 

 of spontaneous activity of rats as well as on their forced activity during a 

 period of starvation following a period of twenty-eight days throughout 

 which the rats had received diets with either high-fat (80% of total calories) , 

 high-carbohydrate (0.5% of total calories), or high-protein (19.5% of 

 total calories) contents. Not only was the spontaneous activity in general 

 greater in the case of rats which had previously received the fat diet than 

 in those which had received the other foodstuffs, but also the total forced 

 activity in this group greatly exceeded that in the other groups. The 

 latter phenomenon is partly to be ascribed to the longer survival time of 

 the fat-fed group. These data are summarized in Table 2. 



Table 2 



The Effect of Previous Diet on the Spontaneous and Forced 



Activity and on the Period of Survival of Rats 



DURING Fasting" 



Previous diet* 



Category 



Fat 



Carbohydrate 



Protein 



Spontaneous activity, 

 cage revolutions 

 2-4 days 

 9-11 days 

 16-18 days 

 Forced activity, cage 



revolutions 

 Survival time, days 



67.30 ± 915(12) 4040 ± 



8800 ± 1020 (i;?) 8660 ± 



7960 ± 7.38(7) 8650 ± 



19700 ± 1780(12) L3800 ± 



18.3 ± 0.44(12) 15.5 ± 



411(16) 

 1017(14) 

 0000(3) 



1630(14) 

 0.46(13) 



3600 

 7220 



6465 

 10.2 



± 262(7) 



± 500 (4) 



- (0) 



± 1650(9) 

 ± 1.68(9) 



" Adapted from L. T. Samuels, R. C. Gilmore, and R. M. Reinecke, /. Nutrition, 36, 

 639-651(1948), p. 644. 



'' Including Standard Error of the Mean. The figures in parentheses designate the 

 number of rats in each group. 



39 L. T. Samuels, R. C. Gilmore, and R. M. Reinecke, /. Nutrilion, 36, 639-651 

 (1948). 



