Effects of dietary guanidinoacetic acid and betaine supplementation on performance, blood biochemical parameters and antioxidant status of broilers subjected to cold stress

This study was conducted to determine the effects of dietary guanidinoacetic acid (GAA) and betaine supplementation on performance, antioxidant status and biochemical parameters of broilers subjected to cold stress. Based on a 2 × 2 factorial arrangement, 384-day-old male broiler chicks (Cobb) were randomly distributed between four experimental diets (with 8 replicates and 12 birds per replicate) included basal diet (as control) and the basal diet supplemented with 1200 mg/kg GAA; 600 mg/kg betaine and 1200 mg/kg GAA + 600 mg/kg betaine. No significant dietary effects were seen on performance, haematological and blood biochemical parameters including plasma glucose, uric acid, total antioxidant status, lactate, lactate dehydrogenase, red blood cell, haemoglobin, haematocrit and heterophil-to-lymphocyte ratios. However, malondialdehyde (MDA), and the activity of creatine kinase (CK), superoxide dismutase (SOD) and glutathione peroxidase (GPx) were affected by the experimental diets. Compared with the other groups, betaine supplementation decreased liver MDA level and SOD activity while increased activity of liver GPx and serum CK and decreased serum level of MDA were observed in birds fed the GAA-included diet. Overall, based on the results, it seems that dietary GAA and betaine could have beneficial effects on antioxidant status of broilers subjected to cold stress