Effect of Cholesterol Feeding on Growth of Rats

Abstract

In this laboratory, during the past few years, we have fed to a total of several hundred young rats diets containing 1% cholesterol. We have found, almost without exception, that if the basic diet to which the cholesterol was added was adequate to support entirely normal growth on a long-time basis, there was no significant difference between the growth curves of the cholesterol-fed animals and those of the littermate controls which received the same diets without the added cholesterol. Moreover, this was true as well for certain vitamin-deficient diets, notably those lacking A.

This finding is entirely at variance with that reported by Sperry and Stoyanoff 1 for synthetic diets. This would seem to indicate the value of analysis of the diets used in the two laboratories with this point in view.

The composition of our diets has already been reported. 2 Extracted casein was used as a source of protein in both laboratories and at levels sufficiently nearly alike as to probably rule out differences in behavior due to protein intake. Sperry, et al., have used sucrose, and we have used starch as a source of carbohydrate. While the cornstarch used in our laboratory certainly did not contain enough betaine, as Best and Ridout 3 have suggested that certain samples of potato starch may, to largely prevent cholesterol ester deposition in the livers of our rats, nevertheless there is no proof that it did not contain some factor which may be necessary for the growth of cholesterol-fed rats.

Again, we have used in this laboratory less highly purified sources of vitamins A, D, and, in some case, B and G, than the Columbia investigators. The behavior of vitamin-deficient animals fed cholesterol in this laboratory has been such as to indicate that lack of none of the vitamins just mentioned is in itself responsible for the retarded growth of Sperry's cholesterol-fed rats, but it does not eliminate the possibility that some other accessory factor associated with our vitamin sources may have made it possible for our cholesterol-fed rats to grow normally.