Isolation of the unidentified growth factor, vitamin B13, in distillers' dried solubles.

Recent investigations have shown that distillers’ dried solubles contain a factor or factors which are necessary for the growth of chicks (1) and rats (2). This factor is distinct from vitamin A, vitamin D, thiamine, riboflavin, inositol, nicotinic acid, pantothenic acid, p-aminobenzoic acid, choline, pyridoxine, biotin, folic acid, or 2-methylnaphthoquinone. A procedure has been developed for the isolation of this unidentified growth factor in a highly concentrated condition. This method is based upon physical and chemical characteristics of the active principles which were discovered during the fractionation studies (2).