|Majak, Walter - RANGE RESEARCH UNIT, CANA|
|Allison, Milton - IOWA STATE UNIVERSITY|
Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 16, 2004
Publication Date: February 18, 2005
Citation: Anderson, R.C., Majak, W., Rasmussen, M.A., Callaway, T.R., Beier, R.C., Nisbet, D.J., Allison, M.J. 2005. Toxicity and metabolism of the conjugates of 3-nitropropanol and 3-nitropropionic acid in forages poisonous to livestock. Journal of Agricultural and Food Chemistry. 53:2344-2350. Interpretive Summary: Nitropropanol and nitropropionic acid are toxic compounds contained in more than 450 different species and varieties of plants distributed throughout the world. When cattle and sheep eat these plants they may become poisoned and die. Evidence has shown that microorganisms in the gut of some animals can degrade the toxins thus allowing the animals to safely eat the plants. One particular microbe, named Denitrobacterium detoxificans, may play a particularly important role in detoxifying the toxins because it metabolizes the toxins faster than any other known bacteria. Research is underway to take advantage of Denitrobacterium detoxificans special detoxification abilities by developing ways to make sure this bacterium is present in all animals that may be eating plants containing the toxins. This research will help farmers and ranchers protect their animals from being poisoned and will ultimately help American consumers by keeping down the costs of animal products they consume.
Technical Abstract: Ether glycosides of 3-nitro-1-propanol (nitropropanol) and glucose esters 3-nitro-1-propionic acid (nitropropionic acid) occur in many leguminous forages distributed throughout the world. Systemically, nitropropionic acid irreversibly inactivates succinate dehydrogenase. Nitropropanol is not toxic per se, but is converted by hepatic alcohol dehydrogenase to nitropropionic acid. Ruminal metabolism of the nitrotoxins occurs and when rates are rapid enough this may provide a mechanism for detoxification. At least 20 different ruminal bacteria strains are known to metabolize the nitrotoxins but most of these appear to play only a minor role in detoxification. Recent evidence suggests that an obligate anaerobic nitro-respiring bacterium, Denitrobacterium detoxificans, may be particularly important in conferring protection to animals consuming plants containing the nitrotoxins as this bacterium metabolizes the toxins at rates near those by mixed ruminal populations. Rates of ruminal nitropropanol metabolism can be enhanced by modifying the rumen environment through dietary manipulations and in some cases this suggests the in vivo enrichment of highly competent nitropropanol-metabolizing bacteria such as D. detoxificans.