Is ALAD activity a good biomarker for chronic lead exposure in birds?

CID F.; FERNÁNDEZ N; CASTILLO LL; CHEDIACK, JG; CAVIEDES-VIDAL E

Mendoza

Congreso; Reunión Anual de la Sociedad Biología de Cuyo; 2013

Sociedad Biología de Cuyo

In recent times, atmospheric lead (Pb) emissions have been reduced significantly. However, Pb is still present in the environment, because it is a persistent metal. Inhibition of ALAD enzyme (δ-aminolevulinic acid dehydratase) is considered a sensitive and useful biomarker to detect Pb exposure in animals. It was extensively used as indicator of Pb contamination. However, there are no studies about the response of this biomarker to chronic Pb exposure in birds. Our objective was to characterize the ALAD biomarker response in Passer domesticus chronically exposed to Pb. To test our goal, birds were acclimated to laboratory conditions with water and food ad libitum. We established three independents groups of birds (n=6), 2 groups were exposed during 15 and 30 days to the same Pb concentration in drinking water, and 1 control group without exposition. At the end of the experiment animals were weighed and blood samples were drawn from brachial vein to determine ALAD activity, hematocrit and hemoglobin. We used an ANOVA with Tukey post-hoc to compare treatments. Our results showed a significant inhibition of ALAD in birds exposed to Pb during 15 days. Surprisingly the animals exposed to Pb during 30 days exhibited a similar ALAD activity than control group. These findings question the utility of ALAD as a biomarker for lead contamination, since in that case birds are chronically exposed to lead. Supported by UNSL 0612 to FDC, PIP2010-12 to JGC and UNSL 9502 to ECV.