Abstract
Summary
Black Leghorn chicks were raised on a basal diet designed to contain the previously recognized chromotrichial factors, except the L. casei factor. Synthetic L. casei factor injected 5 times weekly at a level calculated to supply 10 μg per day showed feathering and pigmentation comparable to that of chicks receiving 10% brewers′ yeast; supplement. Growth was somewhat better om the latter. At a level of 5 μg, feathering was fairly good and depigmentation was marked. At 1 and 2.5 μg levels, feathering was very poor. Growth and feathering were in proportion to the level of L. casei factor used.
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