Excretion, through milk, of ptaquiloside in bracken-fed cows. A quantitative assessment

Abstract

-The content of ptaquiloside (ptaq), a major Pteridium aquilinum carcinogen found in milk from cows fed bracken in Venezuela, has been estimated quantitatively in ils passage through bovines into milk. Six cows were given 6 kg/animal/d of fresh bracken fronds whose ptaq content was determined. Ptaq first appeared in milk 38 h after initially feeding this plant to the cows and continued to be excreted at a relatively constant level, after an induction period, for 62-70 h after the bracken diet had ceased. The average value of total ptaq excreted ([ptaq]e) from milk amounted to 8.60 ± 1.16 % of the total ptaq ingested ([ptaq]) during the entire feeding period.[ptaq]e was linearly dose dependent in the 2 400 to 10 000 mg/animal/d range of ptaq given to the test animais and the ratio [ptaqle/jptaq], remained relatively constant at various ptaq dosages. In a two-pulse feeding sequence with a 72-h interlude when no bracken was given, a bimodal ptaq excretion curve was obtained. The implications to human health are discussed. © InralElsevier, Paris ptaquiloside / bracken fern / cow's milk Résumé -Excrétion du ptaquiloside dans le lait de vaches alimentées avec de la fougère Bracken, Évaluation quantitative. La quantité de ptaquiloside (ptaq), le principal carcinogène de Pteridium aquilinum, retrouvé dans le lait de vaches alimentées avec la fougère bracken au Venezuela, a été estimée quantitativement. On a donné à six vaches 6 kglj de frondes fraîches de fougère, dont le contenu en ptaq a été deterrniné. Le ptaq est apparu d'abord dans le lait 38 heures après la première prise et a continué à être excrété à une concentration plus ou moins constante après une période d'induction, jusqu'à 62-70 heures après que l'alimentation en fougère a cessé. Ensuite, le ptaq a graduellement diminué jusqu'à ce qu'il ait disparu du lait. La valeur moyenne de ptaq excrétée dans le * Correspondence and reprints.

Direct and Indirect Effects of Invasive Plants on Soil Chemistry and Ecosystem Function

“…They also report that ptaquiloside is carcinogenic and that very low concentrations can be dangerous to humans in drinking water. When cows eat ptaquiloside, the toxin can accumulate in milk (Alonso-Amelot et al 1998).…”

Perfil de propriedades rurais com pastos invadidos por Pteridium arachnoideum na região norte de Mato Grosso e prevalência de hematúria enzoótica bovina

“…Bovinos que consomem Pteridium spp. apresentam resíduos de ptaquilo-sídeo, uma substância cancerígena presente nessa planta (Hirono et al 1984), no leite e na carne, em quantidades variáveis (Alonso-Amelot et al 1996, 1998, Fletcher et al 2011, Calderón et al 2013. Embora o efeito carcinogênico da ingestão deste cancerígeno por humanos, juntamente com o leite ou carne contaminados, não seja confirmado, alguns autores acreditam que exista uma relação entre a incidência de neoplasias gástricas em humanos e a ingestão de ptaquilosídeo em regiões invadidas por Pteridium spp.…”

Human Carcinogenesis and Bracken Fern: A Review of the Evidence

“…While these results clearly established a bridge for the passage of these carcinogens from bracken to people's diet, the question remained as to how much of this compound could be present in milk from these animals and if this quantity represented a real human health risk. A recent quantitative estimate [108] showed that 8% of the total ptaquiloside consumed in a 5 day period ended up in the excreted milk in the same period of time. Moreover, the correlation between ingested and excreted illudane was linear in the 2.4 g to 10.0 g per animal/day range.…”