title: Whole-carcass residues of the rodenticide difenacoum in anticoagulant-resistant and -susceptible rat strains (Rattus norvegicus).
abstract: The present study investigated the whole-carcass residue carried by resistant and susceptible laboratory rat strains following 5, 10, or 20 d of feeding on a diet of 25 mg difenacoum/kg bait. The mean whole-carcass residue of difenacoum was determined by high-performance liquid chromatography to be between 0.52 and 0.74 mg/kg body weight in all three rat strains tested. These values were considerably lower than some comparable data previously reported for other species and second-generation rodenticides as well as from mathematical models. The whole-carcass residue of extractable (i.e., nonrefractory) parent compound carried by highly resistant rats fed for 20 d (0.74 mg/kg body wt) is unlikely to present a significantly increased risk to predators compared to the amount carried by susceptible rats after 5 d of feeding (0.52 mg/kg body wt). However, resistant rats are more likely to be available for predation and to be carrying a whole-carcass residue of anticoagulant throughout the duration of a control program.
authors.affiliation: Central Science Laboratory, Sand Hutton, York, North Yorkshire YO18 8TA, United Kingdom. h.atterby@csl.gov.uk
authors.forename: Helen
authors.initials: H
authors.lastname: Atterby
authors.forename: Gerard M
authors.initials: GM
authors.lastname: Kerins
authors.forename: Alan D
authors.initials: AD
authors.lastname: MacNicoll
mesh_terms: D015110:4-Hydroxycoumarins / Q000008:administration & dosage / Q000633:toxicity*; D000821:Animal Feed; D000818:Animals; D000925:Anticoagulants / Q000008:administration & dosage / Q000633:toxicity*; D001780:Blood Coagulation Tests; D001835:Body Weight / Q000187:drug effects; D002851:Chromatography, High Pressure Liquid; D004351:Drug Resistance; D010573:Pesticide Residues / Q000378:metabolism / Q000633:toxicity*; D051381:Rats; D018570:Risk Assessment; D012378:Rodenticides / Q000008:administration & dosage / Q000633:toxicity*; D013997:Time Factors
chemical_list: D015110:4-Hydroxycoumarins; D000925:Anticoagulants; D010573:Pesticide Residues; D012378:Rodenticides; C012903:difenacoum