Experimental copper and Heliotropium europaeum intoxication in sheep: clinical syndromes and trace element concentrations

Abstract

Merino wethers were used to determine the effects of copper (Cu) and heliotrope (Heliotropium europeaum), given together or separately, on the development of toxicity and trace element concentration in liver and kidney. The 14 sheep fed both Cu and heliotrope were given Cu and heliotrope concurrently (9 sheep) or heliotrope alone for 12 weeks, and then Cu starting 8 weeks after heliotrope consumption ceased (5 sheep). Clinically and biochemically, there was no significant difference between these two regimes. Thirteen developed clinical signs. Of those, three developed haemolysis, eight became jaundiced and two became weak without jaundice. Of the eleven given Cu alone, three developed haemolysis but no jaundice, while there was neither haemolysis nor jaundice in the ten fed heliotrope only, although one died. Throughout the experiments a similar concentration of Cu was found in liver of control and heliotrope groups. The concentration of Cu in the liver of animals fed Cu alone increased to twice, and in groups fed Cu and heliotrope it increased to three times that found in the control groups. In animals which developed haemolysis, the concentration of Cu in the blood rose prior to the onset of haemolysis. It also rose in some animals which became jaundiced, but did not develop clinical haemolysis. Feeding heliotrope alone induced the histologic changes reported in pyrrolizidine alkaloid intoxication, but was not associated with an excessive accumulation of Cu nor the development of clinical illness. However, such sheep were made more susceptible to effects of a second toxin, for in animals given Cu and heliotrope, toxicity of the two substances was markedly enhanced and excessive accumulation of Cu occurred in liver.