title: Dietary guanidino acetic acid is an efficacious replacement for arginine for young chicks.
abstract: Guanidino acetic acid (GAA) is synthesized in the liver and kidney from Arg and Gly and subsequently methylated by S-adenosylmethionine to form creatine. Four bioassays were carried out to determine the capacity of GAA to serve as a dietary replacement for Arg for growing chicks. Broiler chicks were fed Arg-deficient dextrose-casein (0.88% Arg) or corn-corn coproduct-soybean meal (1.0% Arg) basal diets during 9-d battery feeding trials involving 5 pens of 4 chicks per treatment. The dextrose-casein diet was shown to be markedly deficient in Arg as both weight gain and G:F increased (P < 0.01) due to addition of Arg, GAA, or creatine. The optimal level of added GAA was 0.12% of the diet, but this level of GAA or 1.0% creatine-H(2)O did not improve growth performance when added to an Arg-adequate diet. A second assay confirmed this level of optimal Arg in a 2 × 2 factorial arrangement of l-Arg and GAA supplementation. Using a practical-type diet based on corn, corn gluten meal, distillers dried grains with solubles, and soybean meal, similar improvements (P < 0.05) in G:F resulted from addition of 0.25% Arg, 0.12% GAA, or 0.15% creatine·H(2)O. These results demonstrate that 0.12% supplemental GAA, like creatine, produces consistent growth responses in young chicks fed Arg-deficient diets. To provide further evidence of the capacity for GAA to serve as a dietary Arg replacement, the dextrose-casein diet was supplemented with 7 graded doses of Arg in the absence or presence of 0.12% GAA (14 total diets). Quadratic (P < 0.01) responses in weight gain and G:F responses to supplemental Arg were observed. Similar supplemental Arg requirements were estimated in the absence and presence of 0.12% GAA, but GAA elicited a greater improvement (P < 0.05) in G:F when added to Arg-deficient, compared with Arg-adequate, diets. Collectively, these data indicate that GAA can be used as an efficacious replacement for dietary Arg for young chicks.
authors.affiliation: Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana 61801, USA. rdilger2@illinois.edu
authors.forename: R N
authors.initials: RN
authors.lastname: Dilger
authors.forename: K
authors.initials: K
authors.lastname: Bryant-Angeloni
authors.forename: R L
authors.initials: RL
authors.lastname: Payne
authors.forename: A
authors.initials: A
authors.lastname: Lemme
authors.forename: C M
authors.initials: CM
authors.lastname: Parsons
mesh_terms: D000375:Aging; D000821:Animal Feed / Q000032:analysis; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001120:Arginine / Q000378:metabolism*; D002645:Chickens / Q000254:growth & development*; D004032:Diet / Q000662:veterinary*; D005998:Glycine / Q000031:analogs & derivatives* / Q000378:metabolism
chemical_list: D001120:Arginine; C004946:glycocyamine; D005998:Glycine