The iodine content of hen's eggs as affected by the ration

THE increasing use of eggs in the human dietary necessitates a more complete knowledge of the variation in the amounts of the different essential components of the egg. Both the poultryman and the consumer are interested in eggs possessing a maximum nutritive value. The poultry man is also devoting his efforts to the production of eggs which contain the maximum amounts of the essential elements and compounds required for the development of strong, sturdy chicks. A great deal of work has been done on the variations in the amounts of the organic entities of eggs (1). As a result of these investigations it has been definitely established that the vitamin A and vitamin D content of eggs can be greatly influenced by the ration of the bird. Work on the varia tion in the amounts of the minor inorganic elements in the egg has been given but little consideration. Elvehjem, Kemmerer, Hart, and Halpin (2) reported that neither the iron nor the copper content of eggs can be in creased by feeding additional iron or copper. Unpublished work at this Sta tion confirms these results for iron. The iodine content of eggs, like that of other natural food products, appears to be variable. Forbes and co-workers (3) found traces of iodine in eggs. Hercus and Roberts (4) were able to increase the iodine content of eggs by iodine feeding. Simpson and Strand (5) increased the iodine value of eggs from 0.018 mg. to 0.754 mg. per 100 gm. of shell-free egg, by progressively increasing the dose of potassium iodide to 8 mg. daily over a period of four months. Within two weeks after the iodine feeding was discontinued, the iodine content of the egg dropped to 0.08 mg. per 100 gram of shell-free egg. The common use of eggs in the human dietary, especially for infants and invalids, and the rather extensive use of iodine in the treatment of endemic goiter, make it desirable that we have further information on th