University of Guilan Animal Production Research 2252-0872 4 4 2016 02 20 Effect of adding di-ammonium citrate and urea to the diet on performance of broiler chickens under heat stress Effect of adding di-ammonium citrate and urea to the diet on performance of broiler chickens under heat stress 27 36 1636 FA A. Mohit Assistant Professor, Department of Animal Sciences, Faculty of Agricultural Sciences, University of Guilan, Rasht, Iran H. Chezgi MSc Student, Department of Animal Sciences, Faculty of Agricultural Sciences, University of Guilan, Rasht, Iran M. Mohiti-Asli Assistant Professor, Department of Animal Sciences, Faculty of Agricultural Sciences, University of Guilan, Rasht, Iran Journal Article 2016 03 29 This experiment was conducted to investigate effects of blood uric acid on performance and resistance of broilers under heat stress. 200 day old Ross 308 chicks were used in a completely randomized design with 5 treatments, 4 replicates and 10 chicks in each replicate. Chickens were fed from 24 days of age with diets containing 0.35 (U_0.35) and 0.70 (U_0.70) % of urea and 1.29 (A_1.29) and 2.58 (A_2.58) % of di-ammonium citrate and without urea or di-ammonium citrate. During the experiment, weight gain, average feed intake and feed conversion were measured weekly. Heat stress was applied with exposing the birds to a 35 ± 1 ˚C temperature from 28 days of age onwards. At 27 and 41 days of age, two birds from each replicate were selected randomly and blood samples were collected from brachial vein to determine the concentration of serum uric acid and malondialdehyde. The results showed that at 36-42 days of experiment, the FCR of A_2.58(1.96) was significantly (<em>P</em><0.05) lower than that in U_0.7(2.38), but there was no significant difference with control (2.05) group (<em>P</em>>0.05). The content of serum uric acid of U_0.7 at 27 and 41 days (2.38 and 6.03 mg/dL respectively) was significantly higher than the control (<em>P</em><0.05). The content of serum malondialdehyde was significantly lower in U_0.7 (0.923 μmol/L) and A_2.58 (1.06 μmol/L) than control (1.28 μmol/L) group at 41 days of age (<em>P</em><0.05). This study showed that the addition of urea or diammonium citrate to broiler diet can improve oxidative stress by increasing the concentration of uric acid. This experiment was conducted to investigate effects of blood uric acid on performance and resistance of broilers under heat stress. 200 day old Ross 308 chicks were used in a completely randomized design with 5 treatments, 4 replicates and 10 chicks in each replicate. Chickens were fed from 24 days of age with diets containing 0.35 (U_0.35) and 0.70 (U_0.70) % of urea and 1.29 (A_1.29) and 2.58 (A_2.58) % of di-ammonium citrate and without urea or di-ammonium citrate. During the experiment, weight gain, average feed intake and feed conversion were measured weekly. Heat stress was applied with exposing the birds to a 35 ± 1 ˚C temperature from 28 days of age onwards. At 27 and 41 days of age, two birds from each replicate were selected randomly and blood samples were collected from brachial vein to determine the concentration of serum uric acid and malondialdehyde. The results showed that at 36-42 days of experiment, the FCR of A_2.58(1.96) was significantly (<em>P</em><0.05) lower than that in U_0.7(2.38), but there was no significant difference with control (2.05) group (<em>P</em>>0.05). The content of serum uric acid of U_0.7 at 27 and 41 days (2.38 and 6.03 mg/dL respectively) was significantly higher than the control (<em>P</em><0.05). The content of serum malondialdehyde was significantly lower in U_0.7 (0.923 μmol/L) and A_2.58 (1.06 μmol/L) than control (1.28 μmol/L) group at 41 days of age (<em>P</em><0.05). This study showed that the addition of urea or diammonium citrate to broiler diet can improve oxidative stress by increasing the concentration of uric acid. https://ar.guilan.ac.ir/article_1636_dc82341bef93fa40e5e4eadd1979bb39.pdf