The dietary toxicity of flocoumafen to hens: Elimination and accumulation following repeated oral administration

Abstract

In a dietary toxicity study, laying hens received a diet containing the rodenticide flocoumafen at concentrations of 1.5, 5, 10 and 50 mg kg-' for five consecutive days. The LC,, at termination following a 28-day observation period was 16.4 mg kg-'.Livers of birds which received doses of flocoumafen between 5 and 50 mg kg-l had concentrations of flocoumafen (1.5 nmol g-l) that were independent of dose. The data indicate the presence in hen liver of a saturable high-affinity flocoumafen binding site with similar characteristics and capacity to that of the quail and rat. Residues of flocoumafen in samples of breast and leg muscle were low in all exposure groups. Higher, dose-related residues were found in samples of abdominal fat and skin-associated fat and there was a clear demonstration of the transfer of dose-related residues into eggs.In a separate study in which hens were dosed with [14C]flocoumafen for five consecutive days at a daily rate of 1 and 4 mg kg-l body weight, the majority (68 %) of the daily radioactive dose was eliminated over the following 24 hours via excreta. Residues in liver at death or when killed accounted for < 1 % of the cumulative administered radioactivity. Residues in eggs were located primarily in the yolk with maximum concentrations 1.0 mg kg-' or 0.18% of the low dose; 2.1 mg kg-' or 0.06% of the high dose as ["C]flocoumafen equivalents were observed at 10 days after start of dosing. Some 40 % of the total activity in the yolk was unchanged flocoumafen.

Continued Anticoagulant Rodenticide Exposure of Red‐tailed Hawks (Buteo jamaicensis) in the Northeastern United States with an Evaluation of Serum for Biomonitoring

“…The authors suggest that the apparent ability of brodifacoum to limit the concentration of chlorophacinone may be due to saturation of common hepatic AR binding sites. A limit on hepatic accumulation potentially due to saturation of binding sites was also found in Japanese quail, laboratory rats, and broiler chickens administered flocoumafen (Huckle et al 1988, 1989; Eadsforth et al 1993). The findings by Rattner et al (2020) elucidate the complexities of interpreting AR liver concentrations in wildlife.…”

“…Historical studies on DDT in birds determined that depots of this pesticide stored in fat presented a hazard during times of stress and fat mobilization (Ecobichon and Saschenbrecker 1969; Van Velzen et al 1972). Although fat is not the most significant site of accumulation for ARs, in laying hens (strain ISA Brown broiler chickens) administered flocoumafen, residues of this SGAR were detected in abdominal and skin‐associated fat (Eadsforth et al 1993). Residues of bromadiolone were also found in skin and adherent fat in experimentally dosed hogs (Enouri et al 2015).…”

Biomarkers Potency to Monitor Non-target Fauna Poisoning by Anticoagulant Rodenticides

“…Conversely, while they are also found in liver, a significant amount of FGAR molecule circulates through the blood ( 78 , 83 ). In addition, AR molecules can be excreted in milk and egg ( 84 , 85 ). After an oral intake, the maximum liver concentration of the majority of AR molecule is reached in 4–8 h ( 66 , 83 , 86 ).…”

“…There are few studies on the risk of the consumption of products from exposed animal. However, as AR can be excreted in milk and eggs ( 84 , 85 ), it is advisable to withdraw these products from human and animal consumption and to contact a veterinary poison control center.…”