Histamine, Tyramine, Tryptamine and Electrolytes during Glucose Induced Lactic Acidosis

Abstract

Two trials were conducted to study ruminal lactic acid, histamine, tyramine and tryptamine concentrations following glucose engorgement in vitro and in vivo. Also, electrolyte changes in rumen fluid, blood plasma and urine during lactic acidosis were examined. Experiment 1 involved the addition of glucose to rumen fluid in vitro. After 30 hr of incubation, decreases in pH and increases in lactic acid were consistent with the expected development of acidosis. Tyramine levels increased dramatically. When graded levels of L-histidine were added with glucose, histamine concentrations increased accordingly. In the second experiment, four ewes were dosed with a mixture of 90% glucose and 10% casein. Ruminal pH values decreased while the ruminal lactic acid concentrations increased. Ruminal tyramine and tryptamine concentrations increased. The ruminal histamine concentration did not change significantly. Significant changes were observed in ruminal concentrations of calcium, magnesium and sodium in plasma, and concentrations of magnesium, sodium, potassium, and inorganic phosphate in urine.