Reproduction and Lactation of Mice on Highly Purified Diets

Abstract

Mice have been raised to the fourth generation of offspring on a diet in which all of the vitamins, the essential fatty acids and salts were supplied as chemically pure compounds, the rest of the diet being of highly purified materials. Fertility, as measured by the number of litters born and size of litters, was equal to that on a good stock diet, but growth during the preweaning period was subnormal and the mortality rate during the same period was higher than that of the stock animals. This would indicate that the diet used was not adequate. Nothing can be said in regard to the particular type of deficiency with which we are dealing. It may be (1) an unknown substance, (2) an inadequate amount of one or more of the known dietary essentials, or (3) an imbalance of these known essentials. It does appear that 2% of liver extract will not completely correct the inadequacy of the diet.