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:Herbal methionine can be compared relative to Dl-methionine with evaluation of bioavailability of this source of methionine. OBJECTIVES: An experiment was carried out to determine the relative bioefficacy of herbal methionine (H-Met)® relative to DL-methionine (DL-Met) on performance criteria and mmunocompetence of Met sources in male broilers. Atotal of 160 male broilers were fed a Met-deficient basal diet or the basal diet supplemented with three or four concentrations of each Met sources. METHODS: Multiexponential and multilinear regressions were used to determined bioavailability of herbal methionine (HMet)®relative to DL-Met on performance and immunocompetence of broilers. RESULTS: Body weight gain and feed intake of the broilers fed H-Met or DL Met improved in the experiment, regardless of Met sources, relative to those broilers that were fed the basal diet. Immunocompetence of broilers were not significant at 28day of age (p>0.05), whereas the broilers were significantly affected by the additional levels of Met sources at 42 day of age. CONCLUSIONS: The bioefficacy estimates for H-Met® relative to DL-Met on a product basis were 55% for weight gain, 71% for feed intake, 78% for feed conversion ratio, 70% for dilution 1-choloro 2-3-dinitrobenzene (DNCB), 67% for sheep red blood cell (SRBC), and 68% for phytohemagglutinine (PHA-P). The relative effectiveness of H-Met® compared to that of DL-Met is 68% on average across performance criteria and all immune criteria tested. H-Met®can be supplemented as a new and natural source of Met for the poultry industry.

bioefficacy, broilers,immunocompetence, methioninesources, multiregression