Sh Hadinia - Department of Animal Sciences, Faculty of Agriculture and Natural Resources, University of Tehran, Karaj, Iran
M Shivazad - Department of Animal Sciences, Faculty of Agriculture and Natural Resources, University of Tehran, Karaj, Iran
H Moravej - Department of Animal Sciences, Faculty of Agriculture and Natural Resources, University of Tehran, Karaj, Iran
M Alahyari Shahrasb - Department of Animal Sciences, Faculty of Agriculture and Natural Resources, University of Tehran, Karaj, Iran

BACKGROUND: The degree to which the amount of an ingested nutrient is absorbed and available to the body is called bioavailability. OBJECTIVES: Relative effectiveness of herbal methionine (H-Met®) compared to DL-methionine (DL-Met) was investigated in this experiment. METHODS: Exponential regression analysis was used to determine bioefficacy of H-Met® based on body weight gain, feed intake and feed conversion. DLMet and H-Met® were added to a basal diet in 3 and 4 levels, respectively, in starter, grower and finisher periods. Therefore, that met the nutrient and energy requirements of broiler chickens,with the exception of Met+Cys. RESULTS: In the 42-d trial, broilers growth increased significantly (p<0.05), relative to those broilers fed basal diet, regardless of Met sources. Carcass characteristics did not respond significantly to the supplemental Met. CONCLUSIONS: Regression analysis revealed that H-Met®was 52% (body weight gain), 72% (feed intake) and 77% (feed conversion ratio) as efficacious as DL-Met. H-Met® can be administered as a new and a natural source of Met in poultry industry.

herbal methionine, broiler, carcass,bioefficacy