EFFECT OF METHIONINE AND ITS RELATED-COMPOUNDS ON RUMEN BACTERIAL-ACTIVITY

The effect of several methionine sources (L-methionine = L-MET; DL- me thionine = DL-MET, DL-S-methyl-methionine-sulphonium-chloride = SMM; N -hydroxymethyl-DL-methionine-Ca = NHM; methionine-hydroxy-analog free acid=MHA; methionine-sulphoxyde=MSO) on rumen bacterial growth was stu died using a new methodical approach which utilises a methionine free assay medium (Bacto Methionine Assay Media, Difco) supplemented by inc reasing quantities of the methionine sources and inoculated with one d rop of diluted rumen bacteria. The optical density was measured after 18 h incubation on 39 degrees C. L- and DL-MET promoted the highest gr owth response, while SMM and NHM exerted significantly (p < 0.05) lowe r optical densities. MHA and MSO showed no growth response. The method ical approach and the possible bacterial strains, which might have con tributed to the growth response have been discussed.