Compte-rendu et apport de la conférence-débat : "Nature, conditionnalité et verdissement de la PAC : un tournant wallon ?", 9 novembre 2011, Espace Senghor, Gembloux, Belgique

Proceedings of the conference: "Nature, conditionnalité et verdissement de la PAC : un tournant wallon ?". 9th November 2011. Espace Senghor, Gembloux, Belgium. Recently, the European Union (EU) proposed a reform project for the Common Agricultural Policy (CAP). One of the proposed reforms consists of imposing a set aside proportion of 7% of arable land for biodiversity support purposes. A conference on this proposal was held in Gembloux, Belgium, on 9th November 2011. Such a set aside system already exists in neighboring countries. The French and Swiss systems were presented at the conference in order to highlight their advantages and limitations. Scientific arguments underlying such policies were also presented. It was shown that the creation of semi-natural elements within the agricultural matrix is an efficient way to promote biodiversity. Both the quantity and the quality of these elements need to be considered. In addition, biodiversity is likely to provide services to agriculture, notably crop pollination and pest control. Currently, uncertainties remain regarding areas that are eligible to be designated as reaching the 7% threshold. However, based on the most probable scenarios, the current likely eligible areas cover only 4.3% of arable land in Wallonia. Less than 20% of Walloon farms already reach the 7% threshold proposed by the EU. If the European project is approved, it will therefore be of great importance to have some form of societal recognition afforded to farmers for their efforts. In order to optimize the positive effects of the policy on biodiversity, it is also imperative to ensure that a high level of biological quality is reached in the areas dedicated to biodiversity and to monitor this quality using clearly defined objectives. Economical, societal and environmental issues all need to be considered when applying this policy in order to improve agricultural sustainability and to stop the decline in biodiversity in agricultural landscapes

Mobilization of PCBs from blubber to blood in northern elephant seals (<i>Mirounga angustirostris</i>) during the post-weaning fast

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 Año 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 µg/kg lipids at early versus 911.6 ± 513.1 µg/kg lipids at late fasting) whereas they remained fairly constant in outer blubber (572.6 ± 134.8 µg/kg lipids at early versus 659.2 ± 158.8 µg/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 µg/l serum at early versus 7.2 ± 0.9 µg/l at late fasting). The longitudinal changes in circulating total PCBs could not be explained by the changes in serum lipid fractions (cholesterol, phospholipids, triacylglycerols 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

An unexpected parallelism between Vitamin A and PCBs in seal milk

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

Mobilization of PCBs from blubber to blood in northern elephant seals (Mirounga angustirostris) during the post-weaning fast

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