Gard N W, Hooper M J
Institute of Wildlife and Environmental Toxicology, Clemson University, Pendleton, South Carolina 29670.
J Wildl Dis. 1993 Jan;29(1):1-7. doi: 10.7589/0090-3558-29.1.1.
Age-dependent changes in plasma and brain cholinesterase (ChE) activity were characterized in two altricial passerine species: eastern bluebirds (Sialia sialis) and European starlings (Sturnus vulgaris). Plasma acetylcholinesterase (AChE) activity declined rapidly immediately after hatching, while plasma butyrylcholinesterase (BChE) activity increased throughout the nestling period. These patterns continued after birds fledged, since the BChE: AChE ratio was higher in adult birds than fledglings. This is the first confirmation of age-dependent changes in plasma ChE activity in altricial species. Total plasma ChE activity increased with age in both species, which is the reverse of results previously reported for several precocial species. Brain ChE activity increased with age in both species, and did not reach asymptotic levels before young fledged. This corresponded with patterns previously documented in European starlings and three other altricial species. We propose that age and degree of precocity in young birds must be considered when examining sensitivity or evaluating field exposure of birds to ChE-inhibiting compounds.
在两种晚成鸟雀形目鸟类中，即东部蓝鸲（Sialia sialis）和欧洲椋鸟（Sturnus vulgaris）中，研究了血浆和脑胆碱酯酶（ChE）活性随年龄的变化。孵化后，血浆乙酰胆碱酯酶（AChE）活性迅速下降，而血浆丁酰胆碱酯酶（BChE）活性在整个雏鸟期持续增加。这些模式在雏鸟离巢后仍持续存在，因为成年鸟的BChE:AChE比值高于雏鸟。这是首次证实晚成鸟血浆ChE活性随年龄变化。两种鸟类的血浆总ChE活性均随年龄增加，这与之前报道的几种早成鸟的结果相反。两种鸟类的脑ChE活性均随年龄增加，且在雏鸟离巢前未达到渐近水平。这与之前在欧洲椋鸟和其他三种晚成鸟中记录的模式一致。我们建议，在研究鸟类对ChE抑制化合物的敏感性或评估其野外暴露情况时，必须考虑幼鸟的年龄和早熟程度。
