Acute, sub-acute, and sub-chronic effects of polcyclic aromatic hydrocarbons in northern bobwhite quail (colinus virginianus)

Date

2007-12

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Abstract

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.

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Keywords

Sub-chronic, Sub-acute, Acute, Pentoxyresorufin-O-deethylase (PROD), Ethoxyresorufin-O-deethylase (EROD), P450 enzyme system, Polycyclic aromatic hydrocarbons (PAH)

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