title: Subchronic exposure to chlorpyrifos affects energy expenditure and detoxification capacity in juvenile Japanese quails.
abstract: Effects of pesticides on non-target organisms have been studied in several taxa at different levels of biological organization, from enzymatic to behavioral responses. Although the physiological responses may be associated with higher energy costs, little is known about metabolic costs of pesticide detoxification in birds. To fill this gap, we exposed orally (diet) 15-d old Coturnix coturnix japonica individuals to sublethal doses of chlorpyrifos (10 and 20 mg active ingredient/kg dry food) for four weeks. Carboxylesterase (CbE), butyrylcholinesterase (BChE) and acetylcholinesterase (AChE) activities were periodically measured in multiple tissues along with measurements of resting (RMR) and maximum metabolic rates (M(sum)). Furthermore, glucuronic acid in bird excreta was also assessed at the end of the trial. While CbE and BChE activities were inhibited by chlorpyrifos in all tissues during the third and fourth weeks following pesticide treatment, AChE activity was unaffected. At this sampling times, both M(sum) and RMR expansibility decreased. These results suggest that the exposure to chlorpyrifos caused a negative effect on aerobic performance. Additionally, excretion rate of glucuronic acid was up to 2-fold higher in the 20-mg/kg group than in the control and 10-mg/kg chlorpyrifos groups. The inhibition of CbE and BChE activities corroborated that these enzymes are fulfilling their role as bioscavengers for organophosphate pesticides, decreasing its concentration and thus protecting AChE activity against inhibition by chlorpyrifos.
authors.affiliation: Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago, Chile.
authors.forename: Cristóbal
authors.initials: C
authors.lastname: Narváez
authors.affiliation: Laboratorio de Química Ambiental, Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales (IANIGLA)-CONICET, P.O. Box 131, ZC5500, Mendoza, Argentina.
authors.forename: Juan Manuel
authors.initials: JM
authors.lastname: Ríos
authors.affiliation: Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago, Chile.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Píriz
authors.affiliation: Laboratorio de Ecotoxicología, Facultad de Ciencias Ambientales y Bioquímica, Universidad de Castilla-La Mancha, Toledo, Spain.
authors.forename: Juan C
authors.initials: JC
authors.lastname: Sanchez-Hernandez
authors.affiliation: Departamento de Ciencias Ecológicas, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago, Chile; Departamento de Ecología, Center of Applied Ecology & Sustainability (CAPES), Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, 6513677, Santiago, Chile. Electronic address: psabat@uchile.cl.
authors.forename: Pablo
authors.initials: P
authors.lastname: Sabat
mesh_terms: D000818:Animals; D002091:Butyrylcholinesterase / Q000378:metabolism; D043182:Carboxylesterase / Q000378:metabolism; D004390:Chlorpyrifos / Q000633:toxicity*; D002802:Cholinesterases / Q000378:metabolism; D003370:Coturnix / Q000378:metabolism*; D054750:Ecotoxicology; D004734:Energy Metabolism / Q000187:drug effects*; D004785:Environmental Pollutants / Q000633:toxicity*; D013997:Time Factors
chemical_list: D004785:Environmental Pollutants; D043182:Carboxylesterase; D002091:Butyrylcholinesterase; D002802:Cholinesterases; D004390:Chlorpyrifos
keywords: Aerobic performance; Detoxification; Esterases; Organophosphorus pesticides