Research On Animal Production

     Considering the role of arginine in the prevention of ascites and the possibility of replacing this amino acid with Guanidinoacetic acid (GAA), in present study, the effects of different levels of GAA (0.5 and 1 g/kg diet) supplementation in low-protein diets on growth performance and ascites incidence in broiler chickens were investigated. Therefore, a total of 208 male broilers (Ross 308) were used in completely randomize design with four treatment with four replicate in each treatment. The chicks were reared on the floor up to 42 day. Treatments consisted of a normal-protein diet (NPD) according to the National Research Council (1994) and a reduced-protein diet (RPD) with reduced 30 g/kg of crude protein relative to the NPD. Two reduced-protein diets with similar RPD that supplementing with 0.5 and 1 g/kg GAA were also prepared. Results show that levels of protein and GAA supplementation had no significant effect on growth performance and breast and thigh percentage. The relative weight of liver, heart, and right ventricular weight ratio (RV: TV) significantly (P<0.05) increased in the group fed by RPD. Supplementation GAA significantly (P<0.05) decreased the proportions of the liver so that these treatments had no significant difference with the NPD group. Feeding RPD caused a significant decrease in plasma nitric oxide (NO) and uric acid (UA) concentrations and significant increase in malondialdehyde (MDA) and heterophils to lymphocyte ratio. In this situation, the addition of GAA caused restored these parameters to levels similar to NPD. The results showed that addition of GAA to low protein diets had a significant effect on the prevention of ascites. In general, these results confirmed the positive impact of GAA in preventing the occurrence of hypertrophy on the right ventricle and pulmonary hypertension syndrome in broilers.