Degradation of Amino Acids by Pure Cultures of Rumen Bacteria

Abstract

Amino Acid (AA) degradation profiles of five major genera of rumen bacteria were determined using physiological levels of AA under in vitro conditions. The results indicated that (1) not all AA are degraded by all strains of rumen bacteria and (2) degradation occurs at different rates. The genera Megasphaera, Eubacterium and Streptococcus isolate 19D degraded all 14 AA tested. Members of the genus Butyrivibrio totally degraded Ser, Asp and Glu, with Gly being the only AA not attacked. The two subspecies of Selenomonas tested, differed in their AA degradation patterns. Subspecies lactilytica degraded all AA tested except His and Tyr. Subspecies ruminantium could not degrade Gly, Leu, He, Thr, His, Arg, Lys, Trp nor Tyr. Met appeared unique in that it was produced by members of Megasphaera, Eubacterium and isolate 19D of Streptococcus. Selenomonas, Butyrivibrio and Streptococcus isolated 12D, however, degraded Met. It thus appears that the total ruminal degradation of dietary AA occurs as a result of extensive bacterial interaction. Copyright © 1976. American Society of Animal Science . Copyright 1976 by American Society of Animal Science