MINERALS IN NUTRITION 



27 



In order to investigate the nature of the active principle in kelp, which 

 appeared to exercise a protective action against cholesterol injury, an- 

 other series of experiments was planned in which kelp, kelp ash, and a 

 salt mixture resembling the inorganic constituents of kelp, were used as 

 supplements to the ration. The kelp was ashed in a muffle furnace at 

 400° C. for about 48 hours. A representative sample of the ash showed 

 1427 parts per million of iodine, or about one third of that theoretically- 

 present in the kelp. Thus, the kelp ash represented most of the inorganic 

 material of the kelp, minus about two thirds of the iodine. The synthetic 

 salt mixture was prepared to represent as nearly as possible the inorganic 

 composition of the kelp. Salts used contained both the required anions 

 and cations. Excess base was supplied as carbonate, thus introducing no 

 fixed acid radicals not present in kelp. 



For this final series of experiments, 41 rabbits from 6 litters were used. 

 Each litter was divided among the five ration groups, with as even a dis- 

 tribution of sex as possible. The ration groups were as follows: basal 

 ration; basal ration with cholesterol; basal ration with cholesterol and 

 kelp; basal ration with cholesterol and kelp ash; basal ration with choles- 

 terol and synthetic salt mixture. One percent of cholesterol was used 

 in each instance. In the previous experiments cholesterol had been fed 

 ad lib. For the purpose of shortening the duration of the experiment and 

 of insuring a more even consumption of cholesterol regardless of food 

 intake, the cholesterol content of the rations was increased, and exactly 

 300 grams of the ration fed per week. Kelp constituted 34 percent of the 

 ration in which it was used, and furnished approximately 50 milligrams 

 of iodine per 100 grams of feed. The 12 percent of kelp ash used was 

 equivalent to 34 grams of kelp; and 12 percent of the salt mixture pro- 

 vided a similar mixture of inorganic elements with 50 milligrams of 

 iodine per 100 grams of feed. In this way, each rabbit received about the 

 same amount of cholesterol and other supplements per week. After 300 

 grams of the experimental ration had been consumed, the basal ration 

 was fed ad lib. All animals were autopsied at the end of ten or eleven 

 weeks. 



^ ^ ,cx 



Lesio-ni ♦+? ' '': *':* ^ 



-Sex ^ ■? " ^ ^ "^T^ 0^ 9 



natwT, ^ /%cMesferJ if, cholesterol 



conta'n'nQ l°i cho/estei-ol r3'i^. Help r 'Ifi 'ie{a aih 



Chart 2. Blood Cholesterol and Aortic Lesions in Rabbits Fed Cholesterol plus Kelp, 



Kelp Ash, or a Synthetic Salt Mixture. 



Series III. 69-76 days on Experiment. 



Zholesf^ral i- formal 



^alt mixture Controls 



