Abstract:
The aim of the current study was to assess the effect of oral calcium and cholecalciferol
supplementation on several parameters of calcium status in plasma and urine of captive Asian (Elephas maximus;
n = 10) and African elephants (Loxodonta africana; n = 6) and to detect potential species differences. Calcium and
cholecalciferol supplementation were investigated in a feeding trial using a crossover design consisting of five
periods of 28 days each in summer. From days 28–56 (period 2), elephants were fed the Ca-supplemented diet and
from days 84–112, elephants were fed the cholecalciferol-supplemented diet (period 4). The control diet was fed
during the other periods and was based on their regular ration, and the study was repeated similarly during winter.
Periods 1, 3, and 5 were regarded as washout periods. This study revealed species-specific differences with
reference to calcium and cholecalciferol supplementation. Asian elephants showed a significant increase in mean
plasma total calcium concentration following calcium supplementation during summer, suggesting summerassociated
subclinical hypocalcemia in Western Europe. During winter, no effect was seen after oral calcium
supplementation, but a significant increase was seen both in mean plasma, total, and ionized calcium
concentrations after cholecalciferol supplementation in Asian elephants. In contrast, evidence of subclinical
hypocalcemia could be demonstrated neither in summer nor in winter in African elephants, although 28 days of
cholecalciferol supplementation during winter reversed the decrease in plasma 1,25(OH)2-cholecalciferol and was
followed by a significant increase in mean plasma total calcium concentration. Preliminary findings indicate that
the advisable permanent daily intake for calcium in Asian elephants and cholecalciferol in both elephant species at
least during winter might be higher than current guidelines. It is strongly recommended to monitor blood calcium
concentrations and, if available, blood parathyroid hormone levels to adjust the nutritional supplementation for
each individual elephant.
