The Effect of Feeding Antibiotics on the Carbohydrate and Protein Requirements of the Chick

THE feeding of certain antibiotics reduces the dietary requirements of the chick (Biely and March, 1951) and of the rat (Lih and Baumann, 1951) for some of the B-complex vitamins. Little is known, however, about the effect of antibiotics on the dietary requirements for other nutrients, e.g., protein or carbohydrate. The following series of tests with chicks was designed to determine if the inclusion of antibiotics in the diet would affect the dietary requirements for (1) carbohydrates, (2) protein, and (3) the amino acids lysine and tryptophan. EXPERIMENTAL For each of the tests reported herein, the chicks were distributed at random into electrically heated battery brooders and were fed, from the first day after hatching, the experimental rations. They had free access to feed and water throughout the tests. The number of chicks used in each experiment is shown in the tables summarizing the experimental data for each test. Growth . . .