Antiparasite treatments reduce humoral immunity and impact oxidative status in raptor nestlings

Parasites are natural stressors that may have multiple negative effects on their
host as they usurp energy and nutrients and may lead to costly immune
responses that may cause oxidative stress. At early stages, animals may be more
sensitive to infectious organisms because of their rapid growth and partly
immature immune system. The objective of this study was to explore effects of
parasites by treating chicks of two raptor species (northern goshawk Accipiter
gentilis and white-tailed sea eagle Haliaeetus albicilla) against both endoparasites
(internal parasites) and ectoparasites (external parasites). Nests were either treated
against ectoparasites by spraying with pyrethrin or left unsprayed as control
nests. Within each nest, chicks were randomly orally treated with either an antihelminthic
medication (fenbendazole) or sterile water as control treatment. We
investigated treatment effects on plasma (1) total antioxidant capacity TAC (an
index of nonenzymatic circulating antioxidant defenses), (2) total oxidant status
TOS (a measure of plasmatic oxidants), and (3) immunoglobulin levels (a measure
of humoral immune function). Treatment against ectoparasites led to a
reduction in circulating immunoglobulin plasma levels in male chicks. TOS was
higher when not receiving any parasite reduction treatment and when receiving
both endo- and ectoparasitic reduction treatment compared with receiving only
one treatment. TAC was higher in all treatment groups, when compared to
controls. Despite the relatively low sample size, this experimental study suggests
complex but similar relationships between treatment groups and oxidative status
and immunoglobulin levels in two raptor species.
Costs of parasitism, immunoecology,
immunoglobulin, oxidative status.