Effect of supplementation of guanidinoacetic acid and arginine in vegetable diets for broiler on performance, carcass yield and meat quality

Birds fed with vegetable diets rely on the endogenous synthesis of creatine, which requires amino acids, some of which, for example arginine (Arg), are considered essential for several physiological and metabolic functions. Creatine is limited to high energy expenditure cells, particularly muscle cells. The objective of this study was to evaluate the inclusion of guanidinoacetic acid and arginine (as precursors of creatine) in vegetable diets, on the performance, quality, and yield of broiler chickens. The treatments consisted of diets based on corn and soybean meal (T1); corn, soybean meal + 3% meat meal (T2); corn, soybean meal + 0.08% guanidinoacetic acid (T3); and corn, soybean meal + 0.08% L-arginine (T4). The productive performance of the birds aged 7-, 21-, and 42-days-old was determined. Eighteen 7-day-old birds were sacrificed per treatment to evaluate breast and leg yield, and breast muscle fibers, and eighteen 42-day-old birds were sampled per treatment to determine serum uric acid, urea, creatine, lactate, and glucose concentrations. The same birds were slaughtered to calculate carcass yield in relation to live weight and commercial cut yield. The right pectoralis major muscle of each bird was used to test pH, color (luminosity L*, red index a*, and yellow index b*), and loss of water by pressure analysis, and the left side was used to analyze losses by defrosting and cooking. The data were analyzed using the software SAS. Diets to which meat or vegetable meal plus guanidinoacetic acid or L-Arginine were added resulted in higher live weight and breast meat percentage at 7 days old. Feed conversion was affected for a total period of 1 to 42 days of age (P < 0.0002). The birds with a diet supplemented with vegetable and meat meal had better feed conversion when compared to the birds that were fed with other diets. Treatments did not affect carcass and commercial cut yields, percent loss by cooking, pressure and defrosting of the broiler breast meat, or color (L, a*, and b*) and pH values.