References of "Debier, C"
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See detailChanges in trace elements during lactation in a marine top predator, the grey seal
Habran, Sarah ULg; Pomeroy, P; Debier, C et al

in Aquatic Toxicology (2013), 126

Lactation in pinnipeds represents the most significant cost to mothers during the reproductive cycle. Dynamics of trace elements and their mobilization associated with energy reserves during such an ... [more ▼]

Lactation in pinnipeds represents the most significant cost to mothers during the reproductive cycle. Dynamics of trace elements and their mobilization associated with energy reserves during such an intense physiological process remains poorly understood in marine mammals. The changes in tissue concentrations of 11 elements (Ca, Cd, Cr, Cu, Fe, Hg, Ni, Pb, Se, V, and Zn) were investigated in a longitudinal study during the lactation period and during the post-weaning fast period. Blood, milk, blubber, and hair samples were collected sequentially from 21 mother-pup pairs of grey seals (Halichoerus grypus) from the Isle of May in Scotland. Maternal transfer through the milk was observed for all trace elements, except for Cd. As an indicator of the placental transfer, levels in pup lanugo (natal coat) revealed also the existence of maternal transfer and accumulation of all assayed trace elements during the foetal development. The placental and mammary barriers against non-essential metal transfer to offspring appear to be absent or weak in grey seals. Examining the contamination levels showed that this grey seal population seems more highly exposed to Pb than other phocid populations (2.2 mg/kg dw of grey seal hair). In contrast, blood and hair levels reflected a lower Hg exposure in grey seals from the Isle of May than in harbour seals from the southeastern North Sea. This study also showed that trace element concentrations in blood and blubber could change rapidly over the lactation period. Such physiological processes must be considered carefully during biomonitoring of trace elements, and potential impacts that rapid fluctuations in concentrations can exert on seal health should be further investigated. [less ▲]

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See detailEffects of polychlorobiphenyls, polybromodiphenylethers, organochlorine pesticides and their metabolites on vitamin A status in lactating grey seals
Vanden Berghe, M; Weijs, L; Habran, Sarah ULg et al

in Environmental Research (2013), 120(18-26),

Polychlorobiphenyls (PCBs), polybromodiphenylethers (PBDEs) and organochlorine pesticides (OCPs) such as dichlorodiphenyltrichloroethane (DDT) and hexachlorobenzene (HCB) are considered to be endocrine ... [more ▼]

Polychlorobiphenyls (PCBs), polybromodiphenylethers (PBDEs) and organochlorine pesticides (OCPs) such as dichlorodiphenyltrichloroethane (DDT) and hexachlorobenzene (HCB) are considered to be endocrine disruptors in laboratory and wild animals. This study investigated whether these compounds and their hydroxylated metabolites (HO-PCBs and HO-PBDEs) may affect the homeostasis of vitamin A, a dietary hormone, in the blubber and serum of twenty lactating grey seals sampled at early and late lactation on the Isle of May, Scotland. The effect of naturally produced compounds such as the methoxylated (MeO)-PBDEs was also examined. Vitamin A levels in inner blubber (37 ± 9 µg/g wet weight (ww) and 92 ± 32 µg/g ww at early and late lactation, respectively) and serum (408 ± 143 ng/ml and 390 ± 98 ng/ml at early and late lactation, respectively) appeared to be positively related to ΣPCBs, ΣPBDEs and several individual PCB and PBDE congeners in inner blubber and serum. These findings may suggest an enhanced mobilisation of hepatic retinoid stores and a redistribution in the blubber, a storage site for vitamin A in marine mammals, before the onset of lactation. We also reported that serum concentrations of ΣHO-PCBs and 4-OH-CB107 tended to increase circulating vitamin A levels. Although the direction of the relationships may sometimes differ from those reported in the literature, our results are in agreement with previous findings highlighting a disruption of vitamin A homeostasis in the blubber and bloodstream following exposure to environmental pollutants. Previous studies have shown an interesting parallelism between the mobilisation and transfer of vitamin A and those of PCBs in lactating grey seals, contrary to other lipophilic molecules such as vitamin E (Debier et al. 2004; Vanden Berghe et al. 2010). The fact that vitamin A and PCBs appeared to share common mechanisms during this particular physiological state in grey seals (lactation coupled to a total fasting) may also play a role in the different relationships observed between vitamin A and lipophilic pollutants. [less ▲]

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See detailHow are trace elements mobilized during the post-weaning fast in northern elephant seals?
Habran, Sarah ULg; Crocker, D; Debier, C et al

in Environmental Toxicology & Chemistry (2012), 31(10), 2354-2365

Northern elephant seal (Mirounga angustirostris) pups undergo a substantial intertissue reorganization of protein, minerals, and other cellular components during their postweaning development, which might ... [more ▼]

Northern elephant seal (Mirounga angustirostris) pups undergo a substantial intertissue reorganization of protein, minerals, and other cellular components during their postweaning development, which might entail the mobilization of associated contaminants. The authors investigated the changes in concentrations of 11 elements (Ca, Cd, Cr, Cu, Fe, Hg, Ni, Pb, Se, V, and Zn) in a longitudinal study on 22 northern elephant seal pups during the postweaning fast. Slight changes in most element concentrations were observed in blood throughout the fast. Circulating levels of Hg, Se, and Cu appeared less altered during the postweaning fast than during suckling (previously measured). Despite the considerable fat utilization, element concentrations in blubber remained stable throughout the fast (except Fe), which suggests that elements are mobilized from blubber as efficiently as lipids. As indicators of the placental transfer, concentrations in lanugo hair revealed the existence of maternal transfer and accumulation of all assayed trace elements during fetal development. In addition, the new pelage, rapidly produced after weaning, appeared to be an important elimination route for toxic metals like Hg, Cd, and Pb. The high mineral content detected in pup hair suggests that this species would be more exposed to trace elements than other phocids (except Cd and Pb). This statement needs nevertheless further monitoring and toxicological studies to determine better the exposition to trace elements and its potential impact on the northern elephant seal’s health. [less ▲]

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See detailSelective transfer of persistent organic pollutants and their metabolites in grey seals during lactation
Vanden Berghe, M; Weijs, L; Habran, Sarah ULg et al

in Environment International (2012), 46

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See detailFatty acids and stable isotopes in fish and harbour porpoises (Phocoena phocoena) from the North Sea: further insights in their trophic relationships
Drouguet, Olivier; Caut, Stéphane; Haelters, Jan et al

Poster (2007)

Recent observations revealed an increased abundance of the harbour porpoise in the southern part of the North Sea. Concomitant to sightings of living individuals, the number of stranded porpoises ... [more ▼]

Recent observations revealed an increased abundance of the harbour porpoise in the southern part of the North Sea. Concomitant to sightings of living individuals, the number of stranded porpoises displaying lesions linked to fishing nets has also increased this last decade. The increased abundance of porpoises together with the increase in numbers of bycaught animals raised the question of possible competition between porpoises and fishermen in the North Sea. Therefore, a detailed view on harbour porpoise trophic ecology in this region is crucial for their conservation. Stomachs of the washed ashore porpoises were often empty and provided limited information on their recent diet. Another way of looking into the diet of marine mammals is the analysis of blubber. Stable isotopes ratio (d13C and d15N, SI) and fatty acid composition (20 fatty acids, FA) were analyzed in muscle and blubber of 10 freshly stranded harbour porpoises and in 60 potential prey fish from 10 species collected in the North Sea. The SI ratio and FA composition of these fish enabled a clear classification in different trophic levels and different trophic niches. The FA composition was very similar between harbour porpoise blubber and demersal fish, underlining a preferential predation on that resource for the porpoises investigated. A bias might exist for the porpoises: most of the animals were juveniles, and washed ashore during spring. Porpoises might display other feeding habits in other life stages, other periods of the year. These preliminary results however indicate the enhanced accuracy of crossing these biomarker approaches. [less ▲]

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See detailMobilization of PCBs from blubber to blood in northern elephant seals (Mirounga angustirostris) during the post-weaning fast
Debier, C.; Chalon, Carole ULg; Le Boeuf, B. J. et al

in Aquatic Toxicology (2006), 80(2), 149-157

Northern elephant seals (Mirounga angustirostris) are characterized by extended fasting during which they rely entirely on their own body reserves. During fasts, lipids are mobilized from blubber to match ... [more ▼]

Northern elephant seals (Mirounga angustirostris) are characterized by extended fasting during which they rely entirely on their own body reserves. During fasts, lipids are mobilized from blubber to match the energy requirements of the animal. This transfer frees toxic fat-soluble pollutants into the blood circulation, which may exert adverse health effects, especially in young and developing animals. We investigated the dynamics of mobilization of polychlorinated biphenyls (PCBs) from the blubber of northern elephant seal pups during the post-weaning fast. Longitudinal samples of blubber and serum were collected from free-ranging animals throughout the fast at Ano Nuevo, California. Blubber biopsies were separated into inner and outer layers. The PCB profiles of blubber and serum consisted mainly of penta- (PCB-101, -110, -118), hexa- (PCB-138, -153) and hepta- (PCB-180, -183, -187) chlorobiphenyls, which accounted for almost 90% of the total PCB burden. Total PCB concentrations in inner blubber increased significantly between early and late fasting (563.6 +/- 162.0 mu g/kg lipids at early versus 911.6 +/- 513.1 mu g/kg lipids at late fasting) whereas they remained fairly constant in outer blubber (572.6 +/- 134.8 mu g/kg lipids at early versus 659.2 +/- 158.8 mu g/kg lipids at late fasting). A corresponding rise of PCB concentrations was observed in serum during the second half of the fast (3.8 +/- 1.1 mu g/l serum at early versus 7.2 +/- 0.9 mu g/l at late fasting). The longitudinal changes in circulating total PCBs could not be explained by the changes in serum lipid fractions (cholesterol, phospholipids, triacyl glycerols and free fatty acids). The increases in total PCB concentrations in inner blubber and serum were more pronounced in leaner animals, which suggests that they might be more at risk to potential toxic effects. (c) 2006 Elsevier B.V. All rights reserved. [less ▲]

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See detailAn unexpected parallelism between Vitamin A and PCBs in seal milk
Debier, C.; Pomeroy, P. P.; Thomé, Jean-Pierre ULg et al

in Aquatic Toxicology (2004), 68(2), 179-183

Bioaccumulating pollutants such as polychlorinated biphenyls (PCBs) induce a range of adverse effects in mammals. Vitamin A metabolism is prone to such pollutant disruption which may be particularly ... [more ▼]

Bioaccumulating pollutants such as polychlorinated biphenyls (PCBs) induce a range of adverse effects in mammals. Vitamin A metabolism is prone to such pollutant disruption which may be particularly harmful for young animals. During lactation, maternal PCBs are transferred to the offspring through the milk. Seal milk is very fatty and consequently contains large amounts of these persistent lipophilic contaminants. In the present study, we investigated the relationships between PCBs and Vitamins A and E during lactation, in free-ranging grey seals, using longitudinal samples of milk and blubber. We discovered that, unlike Vitamin E or triglycerides, the dynamics of Vitamin A matches closely those of PCBs in milk throughout lactation. Levels of Vitamin A and PCBs remain constant during the first half of lactation and then increase at late lactation, indicating that pups ingesting higher levels of PCBs also ingest higher amounts of Vitamin A. (C) 2004 Elsevier B.V. All rights reserved. [less ▲]

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