The “Cartilage Growth Factor” and Vitamin B6 in the Nutrition of Chicks

In studies on simplified diets for chicks it was found that when all the known factors were supplied, there was failure of growth until certain crude materials were added.Further investigation led to the conclusion that a new growth factor was involved.The basal ration used in these studies consisted of dextrin 64, purified casein 18, Salts 1111 5, soy bean oil 5, brewers' yeast 5, and liver extract 3. A vitamin A and D concentrate was fed separately.Chicks on this ration weighed about 80 gm. at 4 weeks of age, but if cartilage, kidney, brain, liver, wheat middlings, or polished rice were added, the weight was 160 gm.The addition of chondroitin,2 cholic acid,3 or edestin,4 failed to restore growth, thus differentiating the factor from the anti-gizzard erosion factor and arginine.The factor was not extracted from dried kidney by hexane, ether, alcohol, water, dilute acid, or alkali.It was destroyed by strong acid or tryptic digestion.Similar results were obtained with cartilage, but the factor was brought into solution from cartilage by autoclaving for 23 hours with 0.1 N HzS04.From aqueous solution the factor was partially precipitated with 80 per cent alcohol, not extracted with butanol, and not adsorbed on fullers' earth.We prefer to call this factor the "cartilage growth factor" until a more suitable name is available.Since polished rice shows good activity, the factor may be related to the one recently studied by Stokstad and Manning.6