COD-LIVER Oil in Feeds Requires Care to Preserve Vitamin

That the health of human beings and some domestic animals is influenced by a substance obtained from the liver of a salt-water fish seems almost incredible, but this fact has been established by scientific research. Millions of dollars are spent annually in this country for the purchase of cod-liver oil, which is in demand because it is an excellent source of vitamins A and D.

Commercial practices detrimental to the vitamin A of cod-liver oil may be employed unwittingly by the commercial feed producer. For example, much of the codg-liver oil for animal consumption is sold mixed with a feed or a proprietary preparation, and although it may be possible to handle some of these products in such a way as to preserve the vitamin A, as yet this has not been adequately demonstrated. When used as a source of vitamin A in laboratories engaged in nutrition studies, cod-liver oil is either fed separately or mixed with small quantities of the other food, since vitamin A disappears rapidly from cod-liver oil spread over large surfaces, particularly when exposed to light and air. Vitamin D, on the other hand, is comparatively stable under the same conditions. Whether the benefits derived from cod-liver oil supplements to feeds are due to vitamin A or D, or both, it is not always possible to judge, but the full benefit of both vitamins is not assured unless the cod-liver oil is properly handled.

If the diet must be fortified with vitamin A and the feed dealer can not guarantee that the vitamin A of his cod-liver oil product is stable, it is advisable to buy cod-liver oil of a good grade and either give it separately or mix it with the other food shortly before feeding.