HPLC determination of chlorate metabolism in bovine ruminal fluid

Salmonella and Escherichia coli are two bacteria that are important causes of human and animal disease worldwide. Chlorate is converted in the cell to chlorite, which is lethal to these bacteria. An HPLC procedure was developed for the rapid analysis of chlorate (ClO₃ ^?), nitrate (NO₃ ^?), and nitrite (NO₂ ^?) ions in bovine ruminal fluid samples. Standard curves for chlorite, nitrite, nitrate, and chlorate were well defined linear curves with R² values of 0.99846, 0.99106, 0.99854, and 0.99138, respectively. Concentrations of chlorite could not be accurately determined in bovine ruminal fluid because chlorite reacts with or binds a component(s) or is reduced to chloride in bovine ruminal fluid resulting in low chlorite measurements. A standard curve ranging from 25 to 150 ppm ClO₃ ^? ion was used to measure chlorate fortified into ruminal fluid. The concentration of chlorate was more rapidly lowered (P < 0.01) under anaerobic compared to aerobic incubation conditions. Chlorate alone or chlorate supplemented with the reductants sodium lactate or glycerol were bactericidal in anaerobic incubations. In anaerobic culture, the addition of sodium formate to chlorate-fortified ruminal fluid appeared to decrease chlorate concentrations; however, formate also appeared to moderate the bactericidal effect of chlorate against E. coli. Addition of the reductants, glycerol or lactate, to chlorate-fortified ruminal fluid did not increase the killing of E. coli at 24 h, but may be useful when the reducing equivalents are limiting as in waste holding reservoirs or composting systems required for intense animal production.     

Effect of nitroethane and nitroethanol on the production of indole and 3-methylindole (skatole) from bacteria in swine feces by gas chromatography

Indole and 3-methylindole (skatole) are odor pollutants in livestock waste, and skatole is a major component of boar taint. Skatole causes pulmonary edema and emphysema in ruminants and causes damage to lung Clara cells in animals and humans. A gas chromatographic method that originally used a nitrogen–phosphorus detector to increase sensitivity was modified resulting in an improved flame ionization detection response for indole and skatole of 236% and 207%, respectively. The improved method eliminates the large amount of indole decomposition in the injector. A 10 μ g mL^–1 spike of indole and skatole in water and swine fecal slurries resulted in recovery of 78.5% and 96% in water and 76.1% and 85.8% in fecal slurries, respectively. The effect of the addition of nitroethane and nitroethanol at 21.8 mM in swine fecal slurries was studied on the microbial production of indole and skatole. Nitroethane and nitroethanol decreased the production of skatole in swine fecal slurries at 24 h. The nitroethane effect on l-tryptophan-supplemented fecal slurries after 6 and 24 h incubation resulted in a decrease of 69.0% (P = 0.02) and 23.5% skatole production, respectively, and a decrease of 14.9% indole at 6 h, but an increase in indole production of 81.1% at 24 h.     

HPLC determination of chlorate metabolism in bovine ruminal fluid

Salmonella and Escherichia coli are two bacteria that are important causes of human and animal disease worldwide. Chlorate is converted in the cell to chlorite, which is lethal to these bacteria. An HPLC procedure was developed for the rapid analysis of chlorate (ClO(3)(-)), nitrate (NO(3)(-)), and nitrite (NO(2)(-)) ions in bovine ruminal fluid samples. Standard curves for chlorite, nitrite, nitrate, and chlorate were well defined linear curves with R(2) values of 0.99846, 0.99106, 0.99854, and 0.99138, respectively. Concentrations of chlorite could not be accurately determined in bovine ruminal fluid because chlorite reacts with or binds a component(s) or is reduced to chloride in bovine ruminal fluid resulting in low chlorite measurements. A standard curve ranging from 25 to 150 ppm ClO(3)(-) ion was used to measure chlorate fortified into ruminal fluid. The concentration of chlorate was more rapidly lowered (P < 0.01) under anaerobic compared to aerobic incubation conditions. Chlorate alone or chlorate supplemented with the reductants sodium lactate or glycerol were bactericidal in anaerobic incubations. In anaerobic culture, the addition of sodium formate to chlorate-fortified ruminal fluid appeared to decrease chlorate concentrations; however, formate also appeared to moderate the bactericidal effect of chlorate against E. coli. Addition of the reductants, glycerol or lactate, to chlorate-fortified ruminal fluid did not increase the killing of E. coli at 24 h, but may be useful when the reducing equivalents are limiting as in waste holding reservoirs or composting systems required for intense animal production.