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Description:
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Polycyclic aromatic hydrocarbons (PAHs ) are ubiquitous contaminants of aquatic and terrestrial ecosystems . PAHs are known to induce biochemical alterations in exposed animals . The cytochrome P450 enzyme system is known to be a significant Phase I metabolic pathway for the breakdown of PAHs that enter animal systems . Little is known about the effects of PAHs in Northern bobwhite quail (Colinus virginianus ) and other terrestrial avifauna . The objectives of this study were to 1 ) determine if benz[a]anthracene , pyrene , and naphthalene exposure are acutely toxic in quail , and 2 ) determine if sub -acute exposure to benz[a]anthracene in quail would render mortality and produce alterations in enzyme activity , and 3 ) determine if sub -chronic exposure to benz[a]anthracene in quail would produce alterations in enzyme activity . Quail , acutely dosed with benz[a]anthracene , pyrene , and naphthalene experienced no mortality at the limit dose of 2000 mg /kg bodyweight . Additionally , there were no alterations in animal behavior . Sub -acute exposure of quail to benz[a]anthracene did not produce mortality . Quail were exposed to benz[a]anthracene at concentrations of 0 , 0 .1 , 1 , 10 , 100 , and 1000 mg /kg feed for 5 days . Alterations in cytochrome P450 1A and P450 2B were observed . An increasing trend in mean ethoxyresorufin -O -deethylase (EROD ) activity in the liver was observed as exposure level increased . Pentoxyresorufin -O -deethylase (PROD ) activity in the liver in exposed animals was significantly different when compared to the control . EROD activity in the kidney in the sub -acute study was observed to be significant when the interaction between exposure group and time was considered . Sub -chronic exposure of quail to benz[a]anthracene produced alterations in cytochrome P450 1A and P450 2B . Quail were exposed to benz[a]anthracene at concentrations of 0 , 0 .1 , 1 , and 10 mg /kg feed for 1 , 3 , 9 , 30 , and 60 days . EROD activity in the liver was observed to be significant when the interaction between exposure group and time was considered . An increasing trend in mean EROD and PROD activity in the liver and kidney was observed as exposure concentration increased . This study indicates that benz[a]anthracene , pyrene , and naphthalene are not acutely toxic in exposed quail , and benz[a]anthracene exposure affects enzyme activity in quail exposed sub -acutely and sub -chronically . Overall , this study provides evidence that metabolic alterations are experienced by Northern bobwhite quail exposed to PAHs . |