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Research Project: GENETIC IMPROVEMENT OF COLD WATER MARINE FINFISH

Location: National Cold Water Marine Aquaculture Center

Title: Effects of dietary fish oil replacement on fillet lipids in North American Atlantic salmon (Salmo salar) families

Author
item Burr, Gary
item Wolters, William - Bill
item Barrows, Frederic
item Grimm, Casey
item Dowd, Michael - Mike

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 4/8/2014
Publication Date: 8/22/2014
Citation: Burr, G.S., Wolters, W.R., Barrows, F., Grimm, C.C., Dowd, M.K. 2014. Effects of dietary fish oil replacement on fillet lipids in North American Atlantic salmon (Salmo salar) families. International Conference on Recirculating Aquaculture, Roanoke, VA, August 22-24, 2014. Abstract p. x.

Interpretive Summary:

Technical Abstract: Consumers want fish that contain high amount of long-chain omega-3 fatty acids for the health benefits. Fish producers desire to supply fish with these fatty acids while reducing the amount of fish oil included in the diet and replacing the fish oil with alternative oils. Two studies were conducted at the National Coldwater Marine Aquaculture Center (NCWMAC) examining the effects of fish oil reduction and replacement on the fatty acid profiles of Atlantic salmon fillets. The first study was a forty week feeding study was conducted with Atlantic salmon (Salmo salar) smolts in two recirculating aquaculture systems. Twelve salmon (average initial weight 117 g; initial density 9.4 kg/m3) were stocked per tank one fish per family. Two identical systems were used and contained either freshwater (0 ppt) or seawater (around 30 ppt), with the temperature maintained at 13 degrees C by heat pumps/chillers. Fish were fed one of two diets, a control diet containing fishmeal and fish oil, or a marine-free diet that did not contain fishmeal or fish oil. The diets were fed to 6 replicate tanks in each system. The diet did affect the fatty acid composition of the fillets. Fish fed the marine-free diet had significantly less eicosapentaenoic acid (20:5 n-3, EPA) (1.6% of lipids – 9.9% of lipids) docosahexaenoic acid (22:5 n-3, DHA) (0.5% of lipids – 3.2% of lipids) compared to fish fed the reference diet. Overall the salmon had similar performance regardless of diet and there were not any detectable differences in fatty acid profiles due to family. The second study looked the effects of fish oil replacement on 37 different families. A 20 week feeding trial was conducted with Atlantic salmon families at the NCWMAC in Franklin, ME. One hundred fish per tank (three to four fish per family) were stocked into each tank (initial weight 114 g). Fish were fed one of three diets, a fish oil diet, a diet containing flax oil, and a diet containing flax/corn oil blend. The purpose was to determine if different families have the ability to convert the shorter chain omega-3 fatty acids from flax oil into longer chain omega-3 fatty acids. The fatty acid profiles of the fillets varied with the diet, with the fillets of the fish fed diets containing flax oil having higher a-linolenic acid and lower EPA and DHA compared to the fillets of fish fed the fish oil diets. Family effects were detected in only four out of the fourteen measure omega-6 and omega-3 fatty acids. However there was a family effect for both EPA and DHA indicating that these oils might be utilized or stored differently depending on family. The diet had the greatest influence on the fatty acid profile of the fillets, while some fatty acids were affected by the genetics of the family.