Isolation and characterization of ruminal bacteria degrading DHP, the toxic metabolite of mimosine

Presence of 3.4 DHP (3-hydroxy-4 (IH)-pyridone), a toxic metabolite of the nonprotein amino acid mimosine, in Leucaena leucocephaia, a shrub legume wi th a high protein content and good potential for animal feed, limits its us e. However, animals harbouring 3.4 DHP-degrading ruminal bacteria are able to utilize leucaena as a forage. DHP degrading bacteria were isolated from rumen fluid of a goat fed on leucaena using 3.4A medium containing 0.006% F eCl. After 48 hr of incubation, black colonies were isolated that degraded 80 to 90% of 3.4 DHP and 2.3 DHP. Out of 6 selected isolates, 4 were obliga tory anaerobic gram-positive cocci (1.2-1.8 mm), while 2 isolates were obli gatory anaerobic gram-negative rods. Isolate P-15 degraded 3.4 DHP complete ly in a medium containing glucose and peptone. Its morphological and cultur al characteristics showed that it belongs to the rumen Streptococci group. Establishing this strain into the rumen of DHP susceptible animals might be a remedy to the toxicity problem in leucaena fed animals.