The Nature of Egg Yolk Discoloration Produced by Cottonseed Meal

IN THE South where cotton is a major crop, cottonseed meal is abundant and relatively cheap. The protein quality, while not as high as animal protein, satisfies the essential amino acid requirements of poultry to an extent that it is a valuable protein supplement. Except for the rather unfortunate characteristic of producing discolored yolks, cottonseed meal is a good, convenient source of protein for the poultry diet. Research has been done previously in order to ascertain the cause of the egg yolk discoloration brought about by cottonseed meal in the diet. In most cases gossypol, a complex polyhydric naphthalene derivative present in cottonseed meal, has been postulated to be wholly or partially responsible although other workers maintain that gossypol plays no part at all. These conclusions have all been based on feeding trials. No chemical interpretations of the yolk discoloration have been reported. Inasmuch as all biological processes are fundamentally . . .