Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/4/2004
Publication Date: 10/19/2004
Citation: Lodge-Ivey, S.L., May, T., Petersen, M.K., Strickland, J.R. 2004. Determination of methylglyoxal in ruminal fluid by high-performance liquid chromatography using fluorometric detection. Journal of Agricultural and Food Chemistry. 52(23):6875-6878. DOI: 10.1021/jf049736w. Interpretive Summary: Ruminal microbes of ruminants consuming dormant forage or diets high in cereal grains but low in forage may experience growth conditions where carbohydrate is in excess of microbial requirements and nitrogen is limiting. This imbalance may lead to the production of methylglyoxal, a highly reactive and toxic compound that disrupts DNA, inhibits protein synthesis, and kills bacteria. As no analytical test for methylglyoxal in rumen fluid existed, this research was undertaken to develop a high performance liquid chromatography method capable of detecting methylglyoxal in rumen fluid. This method was based on the chemical conversion of methylglyoxal to 6 methylpterin which was separated on the chromatograph and quantified by fluorimetic detection. Recoveries were greater than 80% and coefficients of variation were less than 15%. The method is reliable and repeatable and may be useful in measuring methylgyoxal in rumen fluid as a method of assessing carbohydrate and nitrogen balance.
Technical Abstract: There is no reported method for the quantification of methylglyoxal in ruminal fluid. The method reported here is based on the conversion of methylglyoxal to 6-methylpterin, followed by quantification of the resulting pteridnic compound by fluormetric detection using liquid chromatography. Ruminal fluid was collected and preserved with 1 M HCI at -20 C. Cation exchange prior to derivatization was used to eliminate possible interfering peaks. The detection limit of 0.125 ug/ml was calculated. The recoveries were >80%, and the coefficients of variation were <15%. This method has proven to be rugged and accurate for the detection of methylglyoxal. Concentration in ruminal fluid collected from cows fed diets deficient in degradable intake protein as a marker. Methylglyoxal is produced by ruminal bacteria in response to low nitrogen levels in the rumen. The ruminal methylglyoxal concentration has the potential to be a useful marker to assess ruminal nitrogen status to aid in more accurate diet formulation.