The Nutritional Significance of the Animal Protein Factor and Antibiotics

Abstract

Diets composed wholly of vegetable materials have for some time been known to be inadequate for the growth of chicks (Hammond & Titus, 1944a, b; Rubin & Bird, 1946) or rats (Zucker & Zucker, 1948), even when supplemented with all the previously recognized vitamins. The factor (or group of factors) essential for the growth of animals maintained on these diets came to be called the 'animal protein factor' (APF) and was soon shown, though not a protein, to be present in materials of animal origin, e.g. milk, meat, liver, fish meal and cow manure (Rubin, Groschke & Bird, 1947; Bird, Rubin & Groschke, 1948). The growth of chicks and pigs on wholly vegetable diets was greatly improved by administration of vitamin B