26 



MASS. EXPERIMENT STATION BULLETIN 374 



the excess of basic elements could not be the crucial factor, but there was 

 still the possibility that some substance in kelp in addition to iodine might 

 be efifective in controlling the damage due to cholesterol. 



3 C £ 



A £ C -D 



A A A S. C C 



t I ^ I t 



>S'/- cholesterol 



0.6% chc/eitt 



A A 3 3 



n,a J-. da,:'^) 



MM 4 



cs< cholesterol 



2Sm^. I. ai HldoU^ 



Chart 1. Blood Cholesterol and Aortic Lesions In Rabbits Fed Cholesterol plus Kelp 



or Potassium Iodide. 



Series 1. 61-79 days on experiment. 



In reviewing the data thus far presented, the degree of damage seemed 

 to parallel the length of time during which the cholesterol content of the 

 blood remained high, rather than the actual amount of cholesterol eaten. 

 The experimental period in the second set of experiments was, therefore, 

 lengthened and the rabbits were not sacrificed until a marked degree of 

 high blood cholesterol had existed for six to eight weeks. Longer periods 

 resulted in damage so severe that dififerences in damage due to ration 

 supplements were obscured. At autopsy, the heart, aorta, and liver of 

 each animal were examined as before, and also the kidneys, spleen, and 

 adrenal glands were examined for infiltration and other changes. Four 

 litters were used, under carefully controlled conditions, to check the pro- 

 tective action of kelp observed in earlier experiments. The experimental 

 period was lengthened to seventeen or eighteen weeks. One group of 

 rabbits received the basal ration only; a second group, the basal ration 

 plus {).S percent cholesterol; and a third, cholesterol plus 17 percent of 

 kelp substituted for bran in the basal ration. An attempt was made to 

 have a rabbit of each sex from each litter on the same ration to afford 

 the best possible basis for comparison. 



The protective action of the kelp was less striking than in earlier ex- 

 periments, possibly because of the longer experimental period and the 

 more prolonged cholesterol injury. There was some evidence, however, 

 of protection due to kelp among the male rabbits of each litter. The 

 feeding of cholesterol caused a marked increase in liver weights, but the 

 kelp ration reduced this effect by half. 



