Achromatosis in the Feathers of Chicks Fed Lysine-deficient Diets

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Abstract
Four breeds of chicks, Barred Plymouth Rock, Black Minorca, Black Australorp and a New Hampshire × Barred Plymouth Rock cross developed an achromatosis of the feathers when fed a lysine-deficient diet. Cockerels were more severely affected than pullets. The symptom was not prevented by supplementing the diet with folic acid, iodinated casein, copper or tyrosine. The amino acid composition of achromatous feathers and normally pigmented feathers was similar. However, the tyrosinase activity of feather quill homogenates, as measured by pigment production on incubation with tyrosine, was less in achromatous than in normal feathers.