The bacteriocins of ruminal bacteria and their potential as an alternative to antibiotics.
Beef cattle have been fed ionophores and other antibiotics for more than 20 years to decrease ruminal fermentation losses (e.g methane and ammonia) and increase feed efficiency, and these improvements have been explained by an inhibition of gram-positive ruminal bacteria. Ionophores are not used to treat human disease, but there has been an increased perception that antibiotics should not be used as feed additives. Some bacteria produce small peptides (bacteriocins) that inhibit gram-positive bacteria. In vitro experiments indicated that the bacteriocin, nisin, and the ionophore, monensin, had similar effects on ruminal fermentation. However, preliminary results indicated that mixed ruminal bacteria degraded nisin, and the ruminal bacterium, Streptococcus bovis, became highly nisin-resistant. A variety of ruminal bacteria produce bacteriocins, and bacteriocin production has, in some cases, been correlated with changes in ruminal ecology. Some ruminal bacteriocins are as potent as nisin in vitro, and resistance can be circumvented. Based on these results, ruminal bacteriocins may provide an alternative to antibiotics in cattle rations.
Russell
James B
JB
Agricultural Research Service, USDA and Cornell University, Ithaca, New York 14853, USA. jbr8@cornell.edu
Mantovani
Hilário C
HC
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects*; D001430:Bacteriocins / Q000032:analysis* / Q000494:pharmacology; D002417:Cattle; D024881:Drug Resistance, Bacterial; D005285:Fermentation; D006094:Gram-Positive Bacteria / Q000187:drug effects*; D012417:Rumen / Q000382:microbiology*; D013291:Streptococcus / Q000187:drug effects
D000900:Anti-Bacterial Agents; D001430:Bacteriocins