Formation of methylamine by rumen microorganisms

An unknown ninhydrin positive peak on the chromatograms of amino acid analyzer of alkalified rumen fluid distillate of goats was isolated as DNP-derivative and identified as methylamine. Under normal feeding condition, its concentration in the rumen ranged 0.1-3.9 mgN/100 ml of rumen fluid and the proportion of methylamine in total volatile base, or apparent ammonia, ranged 0.5-13% during post-feeding. When ammonium salt was administered into the rumen with hay-concentrate ration, these values were increased up to 8.1 mgN/100 ml and 25.8% respectively. Concentrations of ammonia and methylamine when aspartic acid or alanine was administered into the rumen in place of concentrate mixture (control) were not markedly different from the control. In the case of arginine, glutamic acid or glycine administration, these concentrations were depressed as compared to the control. There were no distinct differences in the concentration of methylamine between the faunated and unfaunated goats. 14C from 14C-chlorella protein hydrolyzates, U-14C-alanine, 2-14C-glycine or 14C-sodium bicarbonate was incorporated into methylamine in invitro incubation with rumen micro-organisms. When the washed suspensions of rumen bacteria or protozoa were incubated with 14C-chlorella protein hydrolyzates, the radioactivity in methylamine appeared only in the case of bacteria suspensions. After the addition of 15N-ammonium citrate into the rumen, the incorporation of 15N into methylamine was observed during 1-9 hr. (auth.)