DEVELOPMENT OF REFERENCE RANGES FOR PLASMA TOTAL CHOLINESTERASE AND BRAIN ACETYLCHOLINESTERASE ACTIVITY IN FREE-RANGING CARNABY'S BLACK-COCKATOOS (CALYPTORHYNCHUS LATIROSTRIS)

Abstract

Published avian reference ranges for plasma cholinesterase (ChE) and brain acetylcholinesterase (AChE) are numerous. However, a consistently reported recommendation is the need for species-and laboratory-specific reference ranges because of variables, including assay methods, sample storage conditions, season, and bird sex, age, and physiologic status. We developed normal reference ranges for brain AChE and plasma total ChE (tChE) activity for Carnaby's Black-Cockatoos (Calyptorhynchus latirostris) using a standardized protocol (substrate acetylthiocholine at 25 C). We report reference ranges for brain AChE (19-41 lmol/min per g, mean 2166.38) and plasma tChE (0.41-0.53 lmol/min per mL, mean 0.4760.11) (n¼15). This information will be of use in the ongoing field investigation of a paresis-paralysis syndrome in the endangered Carnaby's Black-Cockatoos, suspected to be associated with exposure to anticholinesterase compounds and add to the paucity of reference ranges for plasma tChE and brain AChE in Australian psittacine birds.

Plasma Cholinesterase Activity in Wild Birds from Undisturbed Woodlands in the Central Monte Desert

“…We found no differences between males and females, or between juveniles and adults (Figure A and B), in the species we were able to evaluate. Sex, age, and physiological and reproductive status have been suggested as causes of biological variability in human, rodent, and domestic animal plasma ChE activity (Tecles and Cerón ; Vaughan‐Higgins et al ). In birds, it has been reported that different sexes and ages differ in their enzymatic biochemistry and physiological activity (Maul and Farris ; Roy ; Norte et al ), but this issue is not well defined; other studies like ours found no differences (Zwarg et al ).…”