Oxalates: Only a few plants contain sufficient amounts of sodium and potassium oxalate to be considered toxic. Moreover, ruminants that consume these plants develop increasing amounts of tolerance to oxalate. An oxalate degrading anaerobe microorganism has been isolated from pure culture of rumen bacteria. This organism, Oxalobacter formigens, uses oxalate as a sole energy source and produces carbon dioxide and formate as end products. Studies in animals and human volunteers have indicated that, when administered therapeutically, O. formigenes can establish in the gut and reduce the urinary oxalate concentration following an oxalate load, hence reducing the likely incidence of calcium oxalate kidney stone formation. The findings to date suggest that anaerobic, colonic bacteria such as O. formigenes, that are able to degrade toxic compounds in the gut, may, in future, find application for therapeutic use, with substantial benefit for human health and well-being.
Nitrates: Forage plants and water are common sources of high levels of nitrates.Some of the causes of abnormal accumulation of nitrates in plants are: nitrogen fertilizaton, drought conditions and some herbicidal treatments. Although in the rumen nitrate is readily reduced to nitrite and then to ammonia, the consumption of plant materials with high levels of nitrate might lead to an acute intoxication. Nitrate reduction in the rumen competes with other essential metabolic reactions such as mathanogenesis, end-product formation, and microbial protein synthesis, and its toxicity reduces growth, causes Vitamin A deficiency, abortion, infertility, and goiter.