Effects of dietary supplemental guanidinoacetic acid and betaine on performance, carcass characteristics, meat quality and thyroids hormone of broilers subjected to cold stress

This study was conducted to determine the effects of dietary supplemental guanidinoacetic acid and betaine on performance, carcass characteristics, meat quality and thyroid hormones 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 eight replicates) included basal diet (as control) and the basal diet supplemented with 1200 mg/kg guanidinoacetic acid; 600 mg/kg betaine and 1200 mg/kg guanidinoacetic acid 600 mg/kg betaine. This trial was performed at the Animal Farm of Razi University (March 2015). In order to create cold stress, on 21th day all birds were subjected to a low temperature (12-15°C), which was remained constant until the end of the experiment. There was no significant effect of experimental diets on the chick’s performance, carcass characteristics, thyroid hormones and liver glycogen levels. Increased breast meat was observed in birds fed the guanidinoacetic acid-included diet. Significant increased L* and a* of meat color were detected in birds fed diets supplemented with guanidinoacetic acid and betaine. Decreased crud fat percentage of breast meat was detected in birds fed the betaine-included diet. The meat pH decreased by time. Increased meat pH was observed in birds fed the betaine-included diet. In conclusion, improved yield and decreased crud fat percentage of breast meat were observed in birds fed the guanidinoacetic acid- and betaine-included diets, respectively. Color indices of broiler breast meat was improved by diet supplementation with guanidinoacetic acid and betaine.