The effect of tetrathiomolybdate on copper metabolism in goats : a dissertation submitted in partial fulfilment for the requirements for a Postgraduate Diploma in Agricultural Science at Lincoln University

Abstract

The effect of varied doses of tetrathiomolybdate (TTM) on some aspects of copper (Cu) metabolism in goats (n = 6) was studied. Goats were fed either a low Cu (12.32 mg/Kg DM) (n = 3) or a high Cu (41.60 mg/Kg) (n = 3) diet. After 6 weeks all goats were given TTM. Tetrathiomolybdate was administered at doses of 1, 2, 4 and 6 mg/Kg W during 7, 9, 11 and 13 weeks. The concentration of Cu in plasma and bile Cu excretion was measured prior to and after each TTM injection. The basal plasma Cu concentration in goats fed on low Cu diet and high Cu diet were 0.80-1.02 ug/ml and 1.07-1.17 ug/ml respectively. The basal bile Cu concentration of goats fed low Cu diet and high Cu diet were 0.05 and 0.22 ug/ml respectively. The basal levels of bile Cu excretion in goats fed the low and high Cu diet were 18.56 and 50.76 ug/8h respectively.

The dietary Cu concentration (11.32 VS. 41.60 mg/Kg DM) appeared to have some effect on the plasma Cu concentration (0.08-1.02 in Gp. A compared with 1.07-1.17 ug/ml in Gp. B goats) and bile Cu excretion (18.56 in Gp. A compared with 50.76 ug/8h in Gp. B goats)

Tetrathiomolybdate administration elevated the plasma Cu concentrations above the basal level in goats fed the low Cu diet. However, in goats fed the high Cu diet, administration of only 4 and 6 mg/Kg of TTM administration increased the plasma Cu concentration (Fig. 11 and 12) above the basal level.

All doses of tetrathiomolybdate except the 1 mg/Kg W enhanced the biliary Cu excretion above the basal level in all goats (Fig. 13 and 14). The greatest response was observed in goats administered the highest dose of TTM.

These findings indicate that TTM has marked effects on Cu metabolism.