Inadequacy of Certain Salt Mixtures Used in Studies of Unidentified Growth Factors for Chicks

Abstract

It is known that chicks require several unidentified growth factors, one or more of which may be inorganic. In order to secure unequivocal evidence for the existence of such unidentified growth factors, it is essential that the basal diet used provide all of the known essential nutrients at levels that are high enough to permit the best possible growth. In a number of published reports it appears that less emphasis has been given to the adequacy of known mineral elements than to that of vitamins and amino acids.In our own studies on unidentified factors, with New Hampshire chicks, we were unable to get growth responses from the addition of the ash of crude feedstuffs to a purified diet (sucrose-soybean protein). The diet contained a salt mixture (Briggs et al., 1952) which supplied the known essential minerals in amounts greater than the minimum levels recommended by the National Research Council…