The production of toxic compounds or antibiotics is a common component
of intermicrobial competitive interactions, and many of these toxins
have been adopted and adapted for the control of microbial populations
. One class of these toxins, the bacteriocins, is a heterogeneous grou
p of proteinaceous antibiotics that often display a high degree of tar
get specificity, although many have a very wide spectrum of activity.
To date, only limited information is available concerning the occurren
ce of bacteriocins among ruminal isolates or the sensitivity of rumina
l microorganisms to exogenous bacteriocins. A survey of 50 strains of
Butyrivibrio spp. isolated from a variety of sources (sheep, deer, and
cattle) for bacteriocin production indicated a high incidence of bact
eriocin-like activity (50%). Many of these inhibitory compounds appear
to have a broad spectrum of activity, which suggests that bacteriocin
s may have a significant impact on both the competitive fitness of ind
ividual microbial strains within the rumen and on the overall structur
e of the microbial population within the rumen. Selected bacteriocins
from lactic acid bacteria also were shown to have activity against But
yrivibrio spp. and may have application in ruminant systems. Bacterioc
ins may provide an alternative group of antibiotics for the manipulati
on of ruminal microbial populations. Bacteriocins have significant adv
antages over other antibiotics in target specificity, susceptibility t
o proteolytic digestion, possibility of genetic transfer and manipulat
ion, and, in the case of some bacteriocins derived from lactic acid ba
cteria, a long history of safe use.