Effects of guanidinoacetic acid supplementation to broiler diets with varying energy contents

Abstract

SUMMARY The purpose of this experiment was to determine the effect of guanidinoacetic acid (GAA) addition to diets containing different levels of ME on the growth performance, energy efficiency, and carcass yield of broiler chickens. A total of 1,536 straight-run Cobb 500 broilers were allocated to 24 floor pens (64 birds/pen). The dietary treatments consisted of a 3 × 2 factorial arrangement with different levels of ME [100% (2,988 kcal/kg of starter from 0 to 10 d, 3,083 kcal/kg of grower from 11 to 22 d, and 3,176 kcal/kg of finisher from 23 to 40 d), 95%, and 90% of the Cobb recommendation], with or without GAA (0.06%). Guanidinoacetic acid supplementation improved FCR from 23 to 40 d and 0 to 40 d of age (P ≤ 0.05) and reduced feed intake from 23 to 40 d of age (P ≤ 0.09), with no significant effects on BW gain. Body weight gain was significantly reduced when dietary energy was reduced by 10% from 11 to 22 d, 23 to 40 d, and 0 to 40 d of age (P ≤ 0.05). The energy reduction affected feed intake from 0 to 10 d and 11 to 22 d of age, with no effect during other periods. An interaction was found between energy level and GAA for FCR during the 0 to 40 d of the experiment. Addition of GAA improved the FCR of treatments with higher energy concentrations (100 and 95% of the management guide recommendation). The main effects of GAA supplementation and energy levels on carcass traits were not significant, except that addition of GAA reduced the percentage of liver significantly (P ≤ 0.05). The weight of the small intestine was reduced in the low-energy (90%) diets supplemented with GAA. Supplementation with GAA decreased caloric intake per kilogram of BW gain and per kilogram of carcass weight. It was concluded from the current experiment that GAA has the potential to improve FCR and energy efficiency.