The effect of molybdenum, iron and sulphur on copper metabolism and physiology of sheep

Four experiments were carried out to investigate the effects of the dietary antagonists molybdenum (Mo) or iron (Fe) on copper (Cu) metabolism and physiology of sheep. In experiment 1, dietary Mo or Fe was provided in diets of Charollais cross growing lambs to investigate the effects on Cu status and performance. Dietary Mo or Fe had no effect on lamb performance but there were significant effects on Cu status. Plasma copper (Pl-Cu) concentrations were significantly higher in lambs that received dietary Mo (P<0.001) and ceruloplasmin (CP) activities were significantly lower (P<0.01) in lambs that received dietary Mo. Dietary Mo significantly altered the CP:Pl-Cu ratio in addition to significantly reducing liver Cu concentrations. No clinical symptoms were observed. In experiment 2, the effect of dietary Mo or Fe on immune responses of Charollais cross growing lambs were investigated. Cell mediated and humoral immunity were not affected by dietary treatment despite liver Cu concentrations being significantly lower (P<0.001) in lambs fed dietary Mo. In experiment 3, dietary Mo or Fe was provided in diets to Charollais cross growing lambs to investigate the effects on Cu status and trace element accumulation in the pituitary, ovary, cerebellum and liver. In addition, effects on pituitary function and ovary morphology were investigated. Dietary Mo significantly (P<0.001) reduced Cu concentrations in the liver in addition to significantly increasing (P