Eggs
of Baltic salmon displaying M74, yolk sac mortality syndrome have elevated
levels of cholesterol oxides and the fatty acid 22:6 n-3
J. Pickova, P.C. Dutta, A. Pettersson, L. Frøyland,
A. Kiessling
Aquaculture, 227(1-4): 63-75
Abstract:
In this study, level of cholesterol oxidation
products (COPs), fatty acids and carotenoids were compared between healthy
and M74 yolk sac mortality syndrome-affected eggs in two Swedish stocks of
Baltic salmon (Salmo salar). In addition were eggs from one stock of
Atlantic salmon, originating from a Swedish west coast river analysed. This
syndrome is believed to be the result of a combined environmental load of
anthropogenic substances like chloroorganic pollutants and their
metabolites. The syndrome is so far only found in Baltic salmon spending
their post-smolt period in the Baltic Sea. COPs were significantly higher (p=0.0289)
in Baltic salmon eggs suffering from M74 than in healthy eggs, while no
difference was found between healthy Baltic salmon eggs and those from the
Atlantic stock (p>0.05). The absolute level of COPs varied between
rivers and year classes, while the level of cholesterol was relatively
stable. However, the level of COPs was always higher in the M74-affected
eggs compared to their healthy counterparts. The content of the fatty acid
22:6 n-3 (DHA; docosahexaenoic acid) was higher and astaxanthin lower in
M74-affected eggs (p=0.0056; p=0.0078, respectively) compared
to healthy ones of the same stock and year class.
(Department of Food Science, Swedish University of
Agricultural Sciences, PO Box 7051, S-750 07, Uppsala, Sweden, e-mail: jana.pickova@lmv.slu.se)