Accelerated Rat Growth Rate on Dietary Nitrogen Obtained from Pancreas. ∗

Abstract

During the course of an investigation of the problem of the parenteral utilization of nitrogen derived from protein sources, it became of importance to obtain a readily-available, nutritively-adequate protein as starting material for these studies. One of the methods employed for establishing the nutritive value of the various proteins has been a study of the comparative rates of rat growth on diets which differed from one another only in the kind of dietary protein nitrogen. The standard level of protein used has been 18% of the basal diet, and for each protein source the protein content was calculated on the basis of percent nitrogen of the preparation multiplied by the factor 6.25. Each source of protein nitrogen was thus incorporated in the basal diet in comparable quantities, and, although this nitrogen was not, in all instances, entirely in the form of protein, the various diets used were approximately equivalent in their protein content.

The preliminary data which have been obtained are striking in that they reveal a marked rate of rat growth on a basal diet in which the nitrogen is furnished by a protein preparation derived from pancreas tissue. Indeed, in terms of rate of rat growth, this pancreas product is definitely superior to casein insofar as its capacity to promote the growth of the rat is concerned.

Experimental. Male, white rats of the Yale strain were placed at weaning on one of the several basal diets shown in Table I. In addition, each animal received a daily supplement of 400 mg of dried yeast† and 200 mg of cod liver oil. The based diets were fed ad libitum. The rats were weighed twice weekly; an accurate measure of food consumption was kept.