Protein Utilization in Growing Rats at Different Levels of Intake

Abstract

Four different proteins, lactalbumin, casein, soy protein and wheat gluten, were fed to groups of weanling rats by diets supplying 7 different levels of each protein for a 3-week test period. It is concluded that the net nitrogen utilization is essentially constant for each of these proteins at all levels of intake up to those which will support approximately maximal growth. The relative nutritive value of casein, soy protein, and wheat gluten appear to be 0.7, 0.34, and 0.14 relative to lactalbumin. When the intake of each of these proteins was multiplied by the appropriate factor to yield “lactalbumin equivalents,” the performance of all proteins per lactalbumin equivalent appears to be the same.