Copper, zinc and manganese concentrations in equine liver, kidney and plasma.

This study explores the concentrations of copper, zinc and manganese in various equine organs, with correlations made to the dietary intakes of these minerals in five groups of horses over a six-month period.

Methodology

• The research involved five groups of horses that were fed distinct diets with varying trace mineral concentrations for at least six months.
• The concentrations of copper (Cu), zinc (Zn), and manganese (Mn) were measured in the livers of 125 yearling horses and kidneys of 81 yearling horses.
• Plasma Cu and Zn measurements were also taken for all the horses participating in the study.

Results

• Mean hepatic Cu concentrations varied between 0.27 to 0.33 µmol/g of dry matter (DM) tissue in horses fed diets containing 6.9 to 15.2 mg Cu/kg DM feed.
• Plasma Cu concentrations were observed to range between 22.8 to 28.3 µmol/L.
• The researchers found no straightforward mathematical relationship between plasma and hepatic Cu concentrations.
• Horses that were fed on diets containing 25.6 to 52.2 mg of Zn per kg of DM feed showed hepatic Zn concentrations averaging between 2.75 to 2.91 µmol/g DM tissue.
• Plasma Zn concentrations in horse groups were found to range from 11.7 to 13.5 µmol/L, with no correlation to the hepatic concentrations of the same.
• Hepatic Mn concentrations were between 0.13 and 0.14 µmol/g DM tissue, with renal Zn concentrations ranging between 1.55 to 1.63 µmol/g DM tissue, irrespective of the diet composition.
• For all horse groups, the mean renal Mn concentration was 0.09 µmol/g DM tissue.
• Renal Cu concentrations varied from 0.36 to 0.47 µmol/g DM tissue and appeared to be influenced by the dietary intake of Cu.

Conclusions

• This research provided valuable insights into the dietary intake of copper, zinc, and manganese on their respective concentrations in equine liver, kidneys, and plasma.
• The findings suggest that higher intake of these minerals do not necessarily result in their increased concentrations in the measured organs or plasma.
• The absence of a simple mathematical correlation between plasma and organ-specific concentrations suggests that there might be sophisticated bodily mechanisms regulating these mineral concentrations in equines.