Studies of Amino Acid Diets for the Chick

Abstract

Day-old female New Hampshire chicks fed a diet containing the amino acid mixture of Fisher and Johnson ('56) as the sole source of protein grew as well up to two weeks of age as chicks receiving a similar complete diet containing casein, gelatin, and methionine. Between two and 4 weeks the growth of chicks fed the amino acid diet fell considerably below that of the chicks fed the purified protein diet. The addition of 10% casein to the amino acid diet resulted in growth equal to that of the controls; part of the activity of casein could be attributed to its amino acid content. When the amino acid diet contained 12% of fat, growth was superior to that obtained when the diet contained 4% of fat. This highly improved amino acid diet provides an opportunity for study of unrecognized factors and for determining amino acid requirements and interrelationships.