¹Department of Animal Science, Science and Research Branch, Islamic Azad University, Tehran, IRAN
²Department of Animal Science, Varamin Branch, Islamic Azad University, Tehran, IRAN DOI : 10.9775/kvfd.2017.18407 The present study was conducted to investigate the effects of GAA addition to corn-soybean meal based diets on productive performance, blood biochemical parameters and reproductive hormones of laying hens. Two hundred laying hens were used in a completely randomized design with 5 treatments and 4 replicates (n=10 birds). Birds received basal diets containing 0 (negative control), 0.057, 0.114 and 0.171% GAA/kg of diet. A diet containing 2% meat meal was also considered as positive control. The data for productive performance was recorded during 84 d and blood samples were collected to evaluate the blood biochemical parameters including triglycerides, high and low density lipoproteins, aspartate aminotransferase and alanine aminotransferase and nitric oxide and reproductive hormones (LH and FSH) at 42 and 84 d. Results showed that GAA addition to diet had not significant effects on productive performance but 0.171% GAA addition reduced egg weight (P<0.05) compared with control groups. Also, 0.114% GAA addition to diet increased levels of LH and FSH compared with control groups at 42 and 84 days. It can be concluded that GAA addition to diet is not appropriate strategy for improving performance of laying hens. Keywords : Creatine, Guanidine acetic acid, Laying hens, Nitric Oxide, Productive performance, Reproductive hormones