title: Toxicity and metabolism of the conjugates of 3-nitropropanol and 3-nitropropionic acid in forages poisonous to livestock.
abstract: Glycosides of 3-nitro-1-propanol (nitropropanol) and glucose esters of 3-nitro-1-propanoic acid (nitropropionic acid) occur in many forages distributed throughout the world. Systemically, nitropropionic acid irreversibly inactivates succinate dehydrogenase, thereby blocking ATP formation. Nitropropanol is not toxic per se in mammals but is converted to nitropropionic acid by hepatic alcohol dehydrogenase. Nitrotoxins can be metabolized by rumen microbes, which may provide a mechanism for detoxification. At least 20 different ruminal bacteria are known to metabolize the nitrotoxins, but most appear to play a minor role in detoxification. Evidence suggests that an obligate anaerobic nitro-respiring bacterium, Denitrobacterium detoxificans, may be particularly important in conferring protection to animals consuming the nitrotoxins as this bacterium metabolizes the toxins at rates near those by mixed ruminal populations. Rates of ruminal nitrotoxin metabolism can be enhanced by modifying the rumen environment through dietary manipulations, which suggests in vivo enrichment of competent nitrotoxin-metabolizing bacteria such as D. detoxificans.
authors.affiliation: Food and Feed Safety Research Unit, Southern Plains Agricultural Research Center, Agricultural Research Service, U.S. Department of Agriculture, 2881 F&B Road, College Station, Texas 77845, USA. anderson@ffsru.tamu.edu
authors.forename: Robin C
authors.initials: RC
authors.lastname: Anderson
authors.forename: Walter
authors.initials: W
authors.lastname: Majak
authors.forename: Mark A
authors.initials: MA
authors.lastname: Rassmussen
authors.forename: Todd R
authors.initials: TR
authors.lastname: Callaway
authors.forename: Ross C
authors.initials: RC
authors.lastname: Beier
authors.forename: David J
authors.initials: DJ
authors.lastname: Nisbet
authors.forename: Milton J
authors.initials: MJ
authors.lastname: Allison
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D000818:Animals; D001419:Bacteria / Q000378:metabolism; D008322:Mammals; D009574:Nitro Compounds / Q000032:analysis / Q000378:metabolism* / Q000633:toxicity*; D010947:Plants, Toxic / Q000737:chemistry*; D020005:Propanols / Q000032:analysis / Q000378:metabolism* / Q000633:toxicity*; D011422:Propionates / Q000032:analysis / Q000378:metabolism* / Q000633:toxicity*; D012417:Rumen / Q000378:metabolism / Q000382:microbiology
chemical_list: D009574:Nitro Compounds; D020005:Propanols; D011422:Propionates; C499931:3-nitropropanol; C015392:3-nitropropionic acid