title: The influence of dietary supplementation of arachidonic acid on prostaglandin production and oxidative stress in the Pacific oyster Crassostrea gigas.
abstract: In a previous study, dietary supplementation with arachidonic acid (ARA) to oysters Crassostrea gigas increased haemocyte numbers, phagocytosis, and production of reactive oxygen species level (ROS) by haemocytes (Delaporte et al., 2006). To assess if the observed stimulation of these cellular responses resulted from changes of ARA-related prostaglandin (PG) production, we analysed prostaglandin E2 metabolite (PGEM) content on the same oysters fed three levels of ARA. Dietary supply of polyunsaturated fatty acids (PUFA) could also induce an oxidative stress that could similarly increase cellular responses; therefore, two indicators of oxidative stress were analysed: peroxidation level and antioxidant defence status. Together the observed positive correlation between ARA and PGEM levels and the absence of lipid peroxidation and antioxidant activity changes supports the hypothesis of an immune stimulation via PG synthesis. Although ARA proportion in oyster tissues increased by up to 7-fold in response to ARA dietary supplementation, peroxidation index did not change because of a compensatory decrease in n-3 fatty acid proportion, mainly 22:6n-3. To further confirm the involvement of PG in the changes of haemocyte count, phagocytosis and ROS production upon ARA supplementation, it would be interesting to test cyclooxygenase and lipooxygenase inhibitors in similar experiments.
authors.affiliation: Université de Bretagne Occidentale, Brest, France et UMR 100 Physiologie et Ecophysiologie des Mollusques Marins, Centre IFREMER de Brest, BP70, 29280 Plouzané, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Seguineau
authors.forename: Ilie S
authors.initials: IS
authors.lastname: Racotta
authors.forename: Elena
authors.initials: E
authors.lastname: Palacios
authors.forename: Maryse
authors.initials: M
authors.lastname: Delaporte
authors.forename: Jeanne
authors.initials: J
authors.lastname: Moal
authors.forename: Philippe
authors.initials: P
authors.lastname: Soudant
mesh_terms: D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D016718:Arachidonic Acid / Q000494:pharmacology*; D002374:Catalase / Q000378:metabolism; D049896:Crassostrea / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D019587:Dietary Supplements; D016166:Free Radical Scavengers / Q000378:metabolism; D006434:Hemocytes / Q000187:drug effects; D015227:Lipid Peroxidation; D018384:Oxidative Stress; D010587:Phagocytosis; D010743:Phospholipids / Q000032:analysis / Q000378:metabolism; D011458:Prostaglandins E / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D016166:Free Radical Scavengers; D010743:Phospholipids; D011458:Prostaglandins E; D016718:Arachidonic Acid; D002374:Catalase; D013482:Superoxide Dismutase