Efficacy of guanidinoacetic acid on growth and muscle energy metabolism in broiler chicks receiving arginine-deficient diets

ABSTRACT Guanidinoacetic acid (GAA) is formed from arginine (Arg) and is the immediate precursor to creatine (Cr) and phosphocreatine (PCr), which are important compounds involved in muscle energy homeostasis. This study sought to determine whether GAA could spare Arg in broiler chicks fed an Arg-deficient practical diet. A basal [0.84% standardized ileal digestible (SID) Arg] was supplemented with combinations of L-Arg (0 or 0.16%) and GAA (0, 0.06, or 0.12%) to form a factorial arrangement of diets; the unsupplemented basal served as the negative control (NC). Additionally, the basal was supplemented with 0.32% Arg to generate an Arg-adequate positive control (PC). Mash diets were fed to 8 replicate pens of 5 chicks per treatment from d 8 to 22 posthatch, with measurements including growth performance, blood GAA metabolites, muscle cellular energy markers, and clinical outcomes. Supplementation of 0.16% Arg increased (P