Studies on Ornithine Synthesis in Relation to Benzoic Acid Excretion in the Domestic Fowl

Abstract

The source of ornithine for conjugation with benzoic acid in the chicken was investigated. The growth depression caused by feeding benzoic acid to chicks could be partially reversed by dietary additions of ornithine and arginine but not by glycine, proline, or glutamic acid. In studies with colostomized hens, dibenzoyl ornithine isolated from urine of hens that received intraperitoneal injections of l-arginine-1-C¹⁴ was highly radioactive, whereas no radioactivity was observed in dibenzoyl ornithine isolated from hens receiving uniformly labeled glucose-C¹⁴. Excretion of ornithine from hens receiving 2% of dietary benzoic acid was high, amounting to nearly 40% of dietary arginine equivalent. These studies show that the chicken is apparently unable to synthesize ornithine and that dietary arginine is the source of ornithine for conjugation with benzoic acid.