Efficacy of Dietary Guanidinoacetic Acid in Broiler Chicks by Amanda

Guanidinoacetic acid is formed from Arg and is the immediate precursor to creatine (Cre). A study was conducted to determine the ability for GAA to spare Arg in broiler chicks fed an Arg-deficient practical diet. A common basal diet (0.84% digestible Arg) was supplemented with combinations of Arg (0 or 0.16%) and GAA (0, 0.06, or 0.12%) to form a 2 × 3 factorial arrangement of dietary treatments. Additionally, the basal diet was supplemented with 0.32% Arg (1.16% digestible Arg) to serve as a positive control. Diets were fed in mash form to 8 replicate pens of 5 chicks per treatment from d 8 to 22 post-hatch, with measurements including growth performance, blood and tissue metabolite concentrations, and clinical outcomes. Supplementation of Arg increased (P < 0.05) BWG from d 15 to 22 post-hatch, with the PC diet eliciting greater (P < 0.05) BWG than the NC diet. Supplementation of either Arg or GAA increased (P < 0.05) gain:feed ratio (G:F) from d 15 to 22 and d 8 to 22 post-hatch, with NC-fed birds exhibiting greater (P < 0.05) G:F than PC-fed birds. An interactive effect (P < 0.05) was observed as serum GAA was more responsive to supplementation of GAA compared with Arg. Interactive effects (P < 0.05) due to Arg and GAA supplementation were also observed for concentrations of muscle total creatine, whole breast creatinine, and nearly every AA in serum, and PC-fed birds had greater (P < 0.05) responses for nearly all blood and tissue outcomes compared with NC-fed birds. Very few effects were noted for clinical chemistry and hematological outcomes from this study. Overall, these observations indicate that GAA