Assessment of the Zinc and Copper Status in Alpaca

This study was performed with the aim of investigating the concentration of zinc and copper in the blood of healthy alpacas (Vicugna pacos) kept in central Europe and to compare the concentration of Zn and Cu in plasma and in whole blood. A further objective was to evaluate blood Zn and Cu in relation to different micromineral supplementation, age and sex groups of alpacas. A total of 299 alpacas (224 adults and 75 crias) from 18 farms were included in this study. The concentrations of copper and zinc in plasma/whole blood were measured by flame atomic absorption spectrometry. The results of this study show high individual variability in plasma Zn (median 3.54, range 1.56-8.01 μmol/l), whole blood Zn (median 10.01, range 6.23-75.0 μmol/l), plasma Cu (median 7.53, range 2.93-16.41 μmol/l) and whole blood Cu (median 6.33, range 3.02-13.95 μmol/l). Plasma Zn was not significantly influenced by sex, age or feeding group. Whole blood Zn was only significantly higher in females than in males. The intake of Zn in all groups was equal to or higher than the nutritional recommendation. During excessive supplementation, Zn absorption decreased and thus blood Zn did not reflect the higher intake. Only a weak correlation was found (Spearman correlation coefficient r = 0.384; p > 0.01; n = 204) between plasma and whole blood Zn concentrations. Plasma copper concentration was significantly influenced by age, sex and feeding; whole blood Cu by age and feeding. However, neither plasma Cu nor whole blood Cu reflected the intake of the element. We found a close correlation between plasma and blood copper concentrations (Spearman correlation coefficient r = 0.9043; p ≤ 0.01; n = 99). According to our results, copper in plasma or blood is not a good indicator of copper intake.