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Immunopathology of 8‐week‐old ring‐necked pheasants ( Phasianus colchicus ) exposed to malathion
Author(s) -
Day Brad L.,
Walser Mary M.,
Sharma Jagdev M.,
Andersen David E.
Publication year - 1995
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620141012
Subject(s) - phasianus , malathion , pheasant , biology , immune system , pesticide , toxicology , physiology , cholinesterase , organophosphate , medicine , endocrinology , immunology , zoology , ecology
In addition to their acute neurotoxic effects, some organophosphorus compounds have been shown to have immunotoxic properties. Alterations in the immune system may lead to chronic morbidity and/or mortality that is not readily apparent at the time of initial exposure. Because it often inhabits land that is intensely farmed, the ring‐necked pheasant ( Phasianus colchicus ) may be a suitable biomonitor of agroecosystems, especially those used in the production of corn. We examined immunopathologic effects of a widely used organophosphate insecticide, malathion, on 8‐week‐old, cage‐reared ring‐necked pheasants 3 d after a single oral dose. No differences were seen in hematologic parameters, body weight, or weight of the bursa of Fabricius. Birds given a high dose of malathion (230 mg/kg) displayed significant decreases in absolute and relative thymic and splenic weights ( p ± 0.05). Significant changes were also seen in thymic and splenic histomorphometry ( p ± 0.05). The high‐dose group and, in some cases, the low‐dose group (92 mg/kg) displayed significant histologic lesions. These findings indicate that a single dose of malathion, at the LD50 level (230 mg/kg) and occasionally at 40% of the LD50 level (92 mg/kg), is capable of inducing quantitative and qualitative changes in the lymphoid organs of the ring‐necked pheasant that may affect immune function.