Bioavailability comparison between herbal methionine and DL-methionine on growth performance and immunocompetence basis in broiler chickens

BACKGROUND:Herbal methionine can be compared relative toDl-methionine with evaluation of bioavailability of this source ofmethionine. OBJECTIVES: An experiment was carried out todetermine the relative bioefficacy of herbal methionine (H-Met)®relative to DL-methionine (DL-Met) on performance criteria andimmunocompetence of Met sources in male broilers. Atotal of 160male broilers were fed a Met-deficient basal diet or the basal dietsupplemented with three or four concentrations of each Metsources. METHODS: Multiexponential and multilinear regressionswere used to determined bioavailability of herbal methionine (HMet)®relative to DL-Met on performance and immunocompetenceof broilers. RESULTS: Body weight gain and feed intake of thebroilers fed H-Met or DL Met improved in the experiment,regardless of Met sources, relative to those broilers that were fed thebasal diet. Immunocompetence of broilers were not significant at 28day of age (p>0.05), whereas the broilers were significantlyaffected by the additional levels of Met sources at 42 day of age.CONCLUSIONS: The bioefficacy estimates for H-Met® relative toDL-Met on a product basis were 55% for weight gain, 71% for feedintake, 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 relativeeffectiveness of H-Met® compared to that of DL-Met is 68% onaverage across performance criteria and all immune criteria tested.H-Met®can be supplemented as a new and natural source of Met forthe poultry industry.