Nutritional Investigation of the Metabolism of Glycine and Its Precursors by Chicks Fed a Crystalline Amino Acid Diet

Wixom et al. (1958) presented data suggesting that both serine and aminoethanol exert a sparing effect on the dietary glycine requirement of growing chicks. Subsequently, it was established that serine could replace dietary glycine on a mole for mole basis (Baker et al., 1968; Akrabawi and Kratzer, 1968) . Work with the rat suggests that several metabolites might conceivably serve as a precursor of glycine through one of the following biosynthetic pathways: choline → betaine → dimethylglycine → sarcosine → glycine; and aminoethanol → glycolic acid → glyoxylic acid → glycine ↔ serine (Meister, 1965). The purpose of the two assays reported here was to evaluate several metabolic intermediates in glycine-choline metabolism to determine if their inclusion in a glycinefree diet would elicit a growth response.…