With the objective of searching for native bacteria that degrade mimosine, the 3,4 DHP and the 2,3 DHP in the rumen of animals consuming or not Leucaena leucocephala in the ration, 8 sheep, 4 cows, 1 bull and 4 goats were sampled. A stock of bacteria that degrade mimosine, the 3,4 DHP and the 2,3 DHP between 1,67 x 10(5) at 7,0 x 10(6) c.f.u./ml; 0,67 x 10(5) at 40,0 x 10(6) c.f.u./ml and 1,5 x 10(5) at 17,0 x 10(6) c.f.u./ml, respectively, was found. There was no mimosine in the rumen liquor and the 3,4 DHP concentrations were between 1,5 and 95 mu g/ml. From the 40 isolated strains, 13 degrade the 2,3 DHP and 27 the 3,4 DHP and the mimosine. It is concluded that the representative of the different ruminant species sampled have in their ruminal flora, bacteria capable of degrading the mimosine and its toxic metabolites. Further studies in different regions of the country are required.
