Andrew Strak
-----Original Message-----
From: howgate <phowgate@rsc.co.uk>
To: Shuckmans@aol.com <Shuckmans@aol.com>; seafood@ucdavis.edu
<seafood@ucdavis.edu>
Date: Thursday, November 05, 1998 3:02 PM
Subject: RE:salmon oil's
>On 1 November, Lewis Shuckman asked:
>
>Dear Group:
>Is there a percentage difference of oil's between wild and farmed raised
>salmon. Is one more less or the same.
>
>I can provide some data for Atlantic salmon, Salmo salar.
>
>Three papers give lipid contents of large samples of farmed salmon. The
>summary results are:
>
>Scottish salmon, mean =10.1%, n = 495, s.d = 2.9, (Bell et al);
>Irish salmon, mean = 11.9%, n = 692, s.d = 2.43, (Schallich & Gormley);
>Norwegian salmon, mean = 15.0%, n=145, s.d = 3.0, ( Refsgaard et al).
>
>You will see that the lipid content is high, but perhaps just, if not more,
>important is the high variation. Assume an S.D. of 2.5 for ease of
>calculation and this implies a 95% range of + or - 5 percentage units from
>the mean. Diet has an impact on lipid content, but is small compared with
>biological variation. Bell et al's data came from 5 fish farms using feeds
>of different lipid contents. There was a weak association between lipid
>content in the diet and lipid content in the flesh, but this was almost
>completely obscured by the spread of values around the regression line.
>
>It is usually considered, in Scotland at least, that the lipid content of
>wild salmon is around 7%, but I cannot cite a reference. Shallich & Gormley
>found the lipid content of 295 Irish wild salmon to be 12.25% with an s.d
>of 3.01, essentially not different from the farmed salmon. Andersen et al
>gives a mean lipid content of 6 samples of wild Atlantic salmon 'caught
>off-shore from Canada' of 9.27%. Auersand et al measured lipid contents in
>different parts of Atlantic salmon and cites in the discussion a range of
>5-8% lipid content in wild salmon. The lipid content in the flesh drops
>when gonads form, (Aksnes et al), but typically farmed salmon are harvested
>before they become mature.
>
>The high, and in particular, the very variable, lipid contents in famed
>salmon presents problems for salmon smokers because salt penetration and
>drying rate in the kiln are influenced by lipid content. It is therefore
>difficult to get a consistent cure within a batch of fish.
>
>I am sure there will be data available for other species of salmon, but I
>do not have references.
>
>REFERENCES
>
>Aksnes, A., Gjerde, B. & Roald, S.O., 1986. Biological, chemical and
>organoleptic changes during maturation of farmed Atlantic salmon, Salmo
>salar. Aquaculture, 53, 7-20
>
>Andersen, H.J., Bertelsen, G., Christophersen, A.G., Ohlen, A. & Skibsted,
>L.H. 1990.
>Development of rancidity in salmonoid steaks during retail display. A
>comparison of practical storage life of wild salmon and farmed rainbow
>trout. Zeitschrift für Lebensmittel-Untersuchung und -Forschung, 191,
>119-122.
>
>Aursand, M., Bleivik, B., Rainuzzo, J.R., Jørgensen, L. & Mohr, V. 1994.
>Lipid distribution and composition of commercially farmed Atlantic salmon
>(Salmo salar). Journal of the Science of Food and Agriculture, 64, 239-248.
>
>Bell, J., McEvoy, J., Webster, J.L., McGhee, F., Millar, R.M. & Sargent,
>J.R. 1998.
>Flesh lipid and carotenoid composition of Scottish farmed Atlantic salmon
>(Salmo salar).
>Journal of Agricultural and Food Chemistry, 46, 119-127.
>
>Refsgaard, H.H.F., Brockhoff, P.B. & Jensen, B. 1998. Biological variation
>of lipid constituents and distribution of tocopherols and astaxanthin in
>farmed Atlantic salmon (Salmo salar). Jurnal of Agricultural and Food
>Chemistry, 46, 808-812.
>
>Scallich, E. & Gormley, T.R. 1996. Condition factor, fat content and
>flavour of famed and wild salmon. Farm & Food, 6(3), 28-31.
>
>Peter Howgate
>Aberdeen, Scotland, UK
>
>