Fenitrothion, an organophosphate, affects running endurance but not aerobic capacity in fat-tailed dunnarts (Sminthopsis crassicaudata)

William A. Buttemer*, Paul G. Story, Karen J. Fildes, Russell V. Baudinette, Lee B. Astheimer

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)

Abstract

We measured aerobic metabolism during cold exposure and exercise performance (run duration and oxygen consumption while running at 1 m s-1) in the fat-tailed dunnart Sminthopsis crassicaudata, a dasyurid marsupial, before and after ingestion of 30 mg kg-1 of fenitrothion, an organophosphate (OP) pesticide. Running endurance of OP-exposed animals was less than half that of control animals over the first 3 days after dosing and 55% of control animal endurance on day 5 post-dose. Despite these declines, peak metabolic rate at this running speed (9.3 times basal metabolic rate; BMR) was unaffected by OP exposure. Peak metabolic rate (PMR) and cumulative oxygen consumption during a 1-h exposure to conditions equivalent to -20 °C did not differ between OP-treated and control dunnarts, with PMR averaging 11 times BMR. We conclude that fenitrothion-induced exercise fatigue is not due to limitations in oxygen or substrate delivery to muscle or in their uptake per se, but more likely relates to decreased ability to sustain high-frequency neuromuscular function. The persistence of locomotor impairment following OP exposure in otherwise asymptomatic animals emphasizes the importance of using performance-based measures when characterising sublethal effects of pesticide exposure in an ecological context.

Original languageEnglish
Pages (from-to)1315-1320
Number of pages6
JournalChemosphere
Volume72
Issue number9
DOIs
Publication statusPublished - Jul 2008
Externally publishedYes

Keywords

  • Fenitrothion
  • Marsupial
  • Organophosphate
  • Oxygen consumption
  • Running endurance thermogenesis

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