Effect of ostertagiasis on copper status in sheep: a study involving use of copper oxide wire particles

Abstract

Lambs infected with Ostertagia circumcincta larvae and uninfected controls were either dosed with 5 g copper oxide wire particles (cowr) or remained undosed. The change in abomasal pH was monitored from duodenal digesta and that in liver copper concentration from initial liver biopsy samples and liver obtained at necropsy after 22 days. Infection increased the pH of digesta from 2 · 5 to 4 · 5. The change in liver copper content in sheep not treated with COWP was +6-1 mg (12·6 per cent) and −6·8 mg (13·8 per cent) in control and infected sheep, respectively. Significantly greater amounts of COWP were recovered from the abomasa of infected than from control animals (3 · 6 ± 0 · 23 and 1 · 6 ± 0·55 g, respectively) and hepatic uptake of copper from COWP was 0 · 7 and 1 · 8 per cent of the dose, respectively. There were significant relationships between the pH of duodenal contents and cowr retained, soluble copper concentration in duodenal digesta and hepatic uptake of copper. It was concluded that, through causing an increase in pH in abomasal and duodenal digesta, gastrointestinal nematodes interfere with copper metabolism.