Abstract

Differences between sheep and deer in the effects of molybdenum (Mo) and sulphur (S) on copper (Cu) metabolism were investigated in two dietary experiments each using 8 animals of each species. The animals were offered a hay diet supplemented (Expt 1) to contain 3, 6, 12 or 24 mg MO/kg DM and 2.3 g S/kg DM or (Expt 2) to contain 6, 12, 24 or 48 mg Mo/kg DM and 5.3 g S/kg DM. The duration of the feeding periods was 35 and 16 days, respectively. With the low S diet (Expt 1) total plasma Cu was changed from the pre- experimental level of 0.75 to 0.63, 0.77, 0.81 and 1.03 mg/litre, respectively, in sheep and from 0.95 to 0.77, 0.79, 0.67 and 1.01 mg/litre in deer. The proportion of trichloroacetic acid (TCA) soluble/total Cu was reduced by 0.05, 0.09, 0.07 and 0.21 in sheep and by 0.01, 0.05, 0.08 and 0.11 in deer. With the high S diet (Expt 2) total plasma Cu concentration changed from 0.81 to 0.82, 0.97, 1.43 and 1.41 mg/litre in sheep and from 1.08 to 0.72, 0.96, 0.88 and 1.21 mg/litre in deer. The proportion of TCA- soluble/total Cu was reduced by 0.20, 0.50, 0.60 and 0.63 in sheep and by 0.05, 0.10, 0.23 and 0.48 in deer. This study has shown that Cu metabolism in sheep is more sensitive than in deer to increasing dietary Mo concentration. While plasma total Cu increased with increasing Mo in the diet in sheep, concentrations declined in deer. This was associated with a greater induction of insoluble Cu in plasma in sheep. In both species increased dietary S enhanced the effect of dietary Mo on Cu metabolism, but deer appeared to be more sensitive than sheep to increasing dietary S concentration.

KE, Kelly

Proceedings of the New Zealand Society of Animal Production, Volume 48, , 249-252, 1988