A cross-roads in medicine

Protective effect of zinc supplementation against copper toxicosis in sheep

“…In these studies also, marked changes were found in liver ultrastructure after 12 weeks which were consistent with the impaired liver function and the increased levels of AAT and arginase (Ross,I 966) in the plasma, and confirmed that considerable liver damage had occurred by this time. Similar biochemical changes have been reported previously (Todd & Thompson, 1963;Ross, 1966;Ishmael, Gopinath & Howell, 1972) and it has been reported that morphological and histochemical changes in hepatocytes and Kupffer cells occur several weeks before the onset of the haemolytic crisis (Ishmael, Gopinath & Howell, 1971).…”

“…In contrast, Todd & Thompson (1963) and Ishmael et al (1972) reported that plasma Cu concentrations were unaffected in the period before the crisis. I n most other regards the pattern of development of Cu toxicosis was similar to that described previously (Todd & Thompson, 1963;Ross, 1966;Ishmael et al 1972), with increases in blood Hb concentrations and PCV values occurring immediately before the final increase in blood Cu concentrations. The formation of methaemoglobin and Heinz bodies was also typical of chronic Cu toxicosis in sheep and indicative of considerable oxidant stress in the erythrocytes at this time (Todd & Thompson, 1963).…”

“…Problems may arise with diets containing about 30 mg Cu/kg, but dietary components other than Cu also influence the development of Cu toxicosis (Bremner, 1974). Attempts have been made to prevent the occurrence of the disease by dietary supplementation with molybdenum and sulphate (Ross, 1966;Hogan, Money & Blayney, 1968) but, despite the frequent success of this measure, there has been some reluctance to adopt it in commercial practice for fear of inducing a Cu deficiency state.…”