Abstract:
BACKGROUND : Numbers of giraffes are declining rapidly in their native habitat. As giraffe research and conservation
efforts increase, the demand for more complete measures of the impact of conservation interventions and the
effects of captive environments on animal health and welfare have risen. We compared the ability of six different
enzyme immunoassays to quantify changes in fecal glucocorticoid metabolites (FGM) resulting from three sources:
adrenocorticotropic hormone stimulation test, transport, and time of day that samples were collected.
RESULTS : Two male giraffes underwent ACTH injections; all six assays detected FGM increases following injection
for Giraffe 1, while only three assays detected FGM increases following injection for Giraffe 2. Consistent with other
ruminant species, the two 11-oxoetiocholanolone assays (one for 11,17-dioxoandrostanes and the other for
3α,11-oxo metabolites) measured the most pronounced and prolonged elevation of FGM, while an assay
for 3β,11β-diol detected peaks of smaller magnitude and duration. Both of the 11-oxoetiocholanolone assays
detected significant FGM increases after transport in Giraffes 3–7, and preliminary data suggest FGM detected
by the assay for 11,17-dioxoandrostanes may differ across time of day.
CONCLUSIONS : We conclude the assay for 11,17-dioxoandrostanes is the most sensitive assay tested for FGM
in giraffes and the assay for FGM with a 5β-3α-ol-11-one structure is also effective. 11-oxoetiocholanolone
enzyme immunoassays have now been demonstrated to be successful in a wide variety of ruminant species,
providing indirect evidence that 5β-reduction may be a common metabolic pathway for glucocorticoids in
ruminants. As FGM peaks were detected in at least some giraffes using all assays tested, giraffes appear to
excrete a wide variety of different FGM. The assays validated here will provide a valuable tool for research
on the health, welfare, and conservation of giraffes.
