The Occurrence of Histamine and Tyramine in Rumen Ingesta of Experimentally Over-Fed Sheep

Abstract

Histamine and tyramine have been identified as toxic constituents in the rumen ingesta of experimentally over-fed sheep. Histamine levels of greater than 70 meg. per ml. of ingesta have been obtained. The illness of the sheep was found to be directly correlated with the level of histamine in the ingesta. As the acidity of the ingesta became lower than about pH 5, histamine formation increased. Below pH 4.5, the levels of histamine reached values greater than 70 meg. per ml. of rumen ingesta and the animals became fatally ill.