Plant Pigments in the Nutrition of the Chicken. 20

Karrer, Euler and Rydbom 1 have demonstrated that carotene has provitamin A properties for the chicken but that xanthophyll is without effect in this regard. Evidence has been presented by Capper 2 that carotene is converted to vitamin A by the chicken.

The present experiment was an attempt to confirm the results of Karrer and his associates and to extend the study to include chlorophyll. In addition a study was made of the uric acid 3 content of the blood, it having been observed in earlier studies that this constituent increases in amount in the vitamin A deficient condition. Newly-hatched White Wyandotte chicks were placed upon a vitamin A deficient ration: 52.5% white corn, 20% wheat middlings, 10% dried skim milk, 10% meat scrap, 5% wheat bran, 0.5% sodium chloride, 1% calcite flour and 1% steamed bone meal. Sufficient irradiated ergosterol was used to protect against leg weakness. On this ration retardation of growth begins between 3 and 4 weeks of age. The pigments were dissolved in ethyl laurate and dilutions made with cottonseed oil. The daily allowance of each pigment was 0.03 mg. by capsule. Supplementation with carotene (M.P. 170°-173°) began at 26 days, with xanthophyll (M.P. 173°), at 27 and with chlorophyll at 31 days. An immediate growth response took place when carotene was fed but the birds which received the xanthophyll and the chlorophyll not only failed to grow, but lost weight and died within 2 weeks. Their behavior was essentially that of the non-supplemented control group. Nine or more individuals were used in each group.