Carry-over of pyrrolizidine alkaloids from feed to milk in dairy cows

Ron Laurentius Hoogenboom (1) , Patrick P J Mulder (2) , Marco J. Zeilmaker (3) , Hester J. van den Top (2) , Gerrit J. Remmelink (4) , Esther F.A. Brandon (3) , Mirjam D. Klijnstra (2) , Gerwin A.L. Meijer (4) , Ronald Schothorst (3) , Hans P. van Egmond (2)

1 Bioanalysis and Toxicology
2 Residue and Contaminant Analysis
3 RIVM - National Institute for Public Health and the Environment [Bilthoven]
4 Livestock Research

Pyrrolizidine alkaloids (PAs) are toxins present in many plants belonging to the families of Asteraceae, Boraginaceae and Fabaceae. Particular notorious are PAs present in ragwort species (Senecio), which are held responsible for hepatic disease in horses and cows and may lead to the death of the affected animals. In addition, these compounds may be transferred to edible products of animal origin and as such be a threat for the health of consumers. To investigate the possible transfer of PAs from contaminated feed to milk, cows were put for 3 weeks on a ration with increasing amounts (50-200 g day-1) of dried ragwort. Milk was collected and sampled twice a day, faeces and urine twice a week. For milk, a dose-related appearance of PAs was found. Jacoline was the major component in milk despite being a minor component in the ragwort material. Practically no N-oxides were observed in milk, notwithstanding the fact that they constituted over 80% of the PAs in ragwort. The overall carry-over of the PAs was estimated to be only around 0.1%, but for jacoline 4%. Notwithstanding the low overall carry-over, this may be relevant for consumer health considering the genotoxic and carcinogenic properties demonstrated for some of these compounds. Analysis of the faeces and urine samples indicated that substantial metabolism of PAs is taking place. The toxicity and potential transfer of metabolites to milk is unknown and remains to be investigated.

Mots clés: Life Sciences

Ron Laurentius Hoogenboom, Patrick P J Mulder, Marco J. Zeilmaker, Hester J. van den Top, Gerrit J. Remmelink, et al.. Carry-over of pyrrolizidine alkaloids from feed to milk in dairy cows. Food Additives and Contaminants, 2011, 28 (03), pp.359-372. ⟨10.1080/19440049.2010.547521⟩. ⟨hal-00673673⟩