Effect of Quantity and Source of Dietary Nitrogen on the Utilization of the Hydroxy Analogues of Methionine and Glycine by Chicks

The hydroxy analogues of methionine and glycine as supplements in low-protein chick diets failed to support growth equivalent to the alpha amino compounds (DL-methionine and glycine). 2. Additions of nitrogen in the form of urea or diammonium citrate to the MHA diets caused a marked increase in chick growth response over MHA alone. Urea, added to the sodium glycolate-supplemented diets, increased chick gains over sodium glycolate alone. 3. Feed efficiency of chicks receiving MHA and sodium glycolate-supplemented diets was poorer than that of chicks receiving diets supplemented with DL-methionine and glycine. Additions of urea or diammonium citrate to MHA or sodium glycolate-supplemented diets improved feed efficiency. 4. Chicks appeared to be more tolerant of dietary urea and diammonium citrate in the presence of MHA than in the presence of DL-methionine. 5. The increased chick growth response to dietary urea or diammonium citrate is believed to be the first such observation in chick experiments.