While routine monitoring poultry meat was obtained from breeding hens, dioxins contaminations were detected in Portugal. Levels of 430.9 pg PCDD/F-WHO-TEQ/g 1 were found, which are higher than the official limits legally allowed for this matrix (1.75 pg PCDD/F-WHO-TEQ/g). To identify the magnitude of the contaminations, 60 samples were collected from poultry farms and different matrices, namely: feed, water, wood shavings from the litters, muscle of the breeding hens, hatching eggs collected in the positive farm and muscle collected from broilers farms supplied by the positive breeding farm. The comparison of the dioxins congeners profiles showed that there was a coincidence of peaks of higher relative concentrations in the wood shavings, with the peaks of the highest relative concentration in the hatching eggs, especially the relative concentrations of the congeners 1,2,3,4,6,7,8-HpCDD and OCDD, which may be explained by the role of VLDLy in the delivery of triglycerides to the oocyte, where they will be used as the energy source for the developing embryo. The comparison of the dioxins congeners profiles of the breeding hens muscle with the poultry muscle, showed a coincidence of peaks of higher relative concentrations in the con- geners 1,2,3,7,8-PeCDD, 1,2,3,6,7,8-HxCDD, 1,2,3,4,6,7,8-HpCDD and OCDD which may indicate a dechlorination pathway "in vivo". Results allowed concluding that those wood shavings, improperly used as poultry litters, were certainly the source of contamination of the food chain.
