title: A thicker chorion gives ova of Atlantic salmon (Salmo salar L.) the upper hand against Saprolegnia infections.
abstract: Since the ban of malachite green in the fish farming industry, finding alternative ways of controlling Saprolegnia infections has become of utmost importance. Much effort has been made to elucidate the mechanisms by which Saprolegnia invades fish eggs. Little is known about the defence mechanisms of the hosts, making some eggs more prone to infection than others. One clue might lie in the composition of the eggs. As the immune system in the embryos is not developed yet, the difference in infection levels could be explained by factors influenced by the mother herself, by either transferring passive immunity, influencing the physical aspects of the eggs or both. One of the physical aspects that could be influenced by the female is the chorion, the extracellular coat surrounding the fish egg, which is in fact the first major barrier to be overcome by Saprolegnia spp. Our results suggest that a thicker chorion in eggs from Atlantic salmon gives a better protection against Saprolegnia spp. In addition to the identification of differences in sensitivity of eggs in a fish farm set-up, we were able to confirm these results in a laboratory-controlled challenge experiment.
authors.affiliation: Norwegian Veterinary Institute, Oslo, Norway.
authors.forename: M M
authors.initials: MM
authors.lastname: Songe
authors.affiliation: Aberdeen Oomycete Laboratory, College of Life Sciences and Medicine, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, UK.
authors.forename: A
authors.initials: A
authors.lastname: Willems
authors.affiliation: Aberdeen Oomycete Laboratory, College of Life Sciences and Medicine, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, UK.
authors.forename: M N
authors.initials: MN
authors.lastname: Sarowar
authors.affiliation: Landcatch Natural Selection Ltd, Ormsary Fish Farm, Lochgilphead, Argyll, UK.
authors.forename: K
authors.initials: K
authors.lastname: Rajan
authors.affiliation: Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, Oslo, Norway.
authors.forename: Ø
authors.initials: Ø
authors.lastname: Evensen
authors.affiliation: Landcatch Natural Selection Ltd, Ormsary Fish Farm, Lochgilphead, Argyll, UK.
authors.forename: K
authors.initials: K
authors.lastname: Drynan
authors.affiliation: Norwegian Veterinary Institute, Oslo, Norway.
authors.forename: I
authors.initials: I
authors.lastname: Skaar
authors.affiliation: Aberdeen Oomycete Laboratory, College of Life Sciences and Medicine, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, UK.
authors.forename: P
authors.initials: P
authors.lastname: van West
mesh_terms: D000818:Animals; D002823:Chorion / Q000166:cytology* / Q000276:immunology; D005393:Fish Diseases / Q000276:immunology*; D007239:Infections / Q000276:immunology / Q000662:veterinary*; D046529:Microscopy, Electron, Transmission / Q000662:veterinary; D010063:Ovum / Q000166:cytology* / Q000276:immunology; D020317:Salmo salar; D044762:Saprolegnia / Q000502:physiology*
keywords: Saprolegnia; chorion; infection; oomycete; ova; salmon; saprolegniosis