Carotene and Vitamin A Requirements for White Leghorn Chicks
Four Test Figures and One Plate
W. O. Frohring and
Juro Wyeno
Biological Laboratory of S. M. A. Corporation, Cleveland
1. The minimum vitamin A requirement of the chick is relativelyhigh per pound of body weight as compared to the rat.
2. Theminimum requirement of vitamin A of the White Leghornchickat the age of about 8 weeks is approximately 65 A.D.M.A.unitsper day.
3. Results were obtained by comparing the averagenumber ofdays lived per chick in relation to the number ofunits of vitaminA supplement received as compared to the averageof the controlgroup.
4. Chicks offer interesting possibilitiesas test animals forvitamin A.
5. No cases of slippedtendon were observed in792 White Leghorn chicks depletedin vitamin A, but given adiet adequate in other respects.
6.Practically all of the 792 chicks depleted in vitamin A showedmarked ataxia 3 to 14 days before complete depletion and death,even though given an adequate amount of vitamin D. This suggeststhe undesirability of using the broad term leg weaknessas related to vitamin D deficiency.
7. There is a wide variationin the number of days chicks willlive on a vitamin A-free diet,no doubt due to variation instorage from the egg from whichthe chicks hatched, which inturn was dependent on the storageor ration of the parent fowl.The addition of carotene or vitaminA to the carotene and vitaminA-free ration delayed the appearanceof deficiency symptomsand prolonged life in a rather definiterelation to the amountof carotene or vitamin A added to thediet.