Ashraf S. Alias, Muna H. I. Al-zubaidy, Yaareb J. Mousa, Fouad K. Mohammad
الملخص العربي
Plasma and brain cholinesterase activities were determined in three wild bird species to assess their exposure to organophosphate
and carbamate insecticides which are used in agriculture and public health. In the present study, we used an electrometric method for
measurement of cholinesterase activities in the plasma and whole brain of three indigenous wild birds commonly found in northern
Iraq. The birds used were apparently healthy adults of both sexes (8 birds/species, comprising 3–5 from each sex) of quail (Coturnix
coturnix), collard dove (Streptopelia decaocto) and rock dove (Columba livia gaddi), which were captured in Mosul, Iraq. The mean
respective cholinesterase activities (Δ pH/30 minutes) in the plasma and whole brain of the birds were as follows: quail (0.96 and
0.29), collard dove (0.97and 0.82) and rock dove (1.44 and 1.42). We examined the potential susceptibility of the plasma or whole
brain cholinesterases to inhibition by selected insecticides. The technique of in vitro cholinesterase inhibition for 10 minutes by the
organophosphate insecticides dichlorvos, malathion and monocrotophos (0.5 and 1.0 μM) and the carbamate insecticide carbaryl
(5 and10 μM) in the enzyme reaction mixtures showed significant inhibition of plasma and whole brain cholinesterase activities to
various extents. The data further support and add to the reported cholinesterase activities determined electrometrically in wild birds
in northern Iraq. The plasma and whole brain cholinesterases of the birds are highly susceptible to inhibition by organophosphate
and carbamate insecticides as determined by the described electrometric method, and the results further suggest the usefulness of
the method in biomonitoring wild bird cholinesterases.