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Title: Enzymatic Digestion of Eye and Brain Tissues of Sockeye and Coho Salmon, and Dusky Rockfish Commercially Harvested in Alaska

Author
item REPPOND, K. - NOAA/NMFS
item OLIVEIRA, A.C.M. - UNIVERSITY OF ALASKA
item Bechtel, Peter

Submitted to: Journal of Aquatic Food Product Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/14/2008
Publication Date: 7/1/2009
Citation: Reppond, K., Oliveira, A., Bechtel, P.J. 2009. Enzymatic Digestion of Eye and Brain Tissues of Sockeye and Coho Salmon, and Dusky Rockfish Commercially Harvested in Alaska. Journal of Aquatic Food Product Technology. 18(3):209-222. Available: http://www.informaworld.com/smpp/title~content=t792303960~db=all.

Interpretive Summary: Potential feed ingredients with high lipid content were made by enzymatic digestion followed by centrifugation of eye tissue from dusky rockfish, coho and sockeye salmon and brain tissue from sockeye salmon. Lipids from digested eye tissue were predominately triacylglycerides; whereas, lipid from digested brain tissue was predominantly phospholipids and sterols. The supernatant fractions made from the from the eye tissues contained high levels of triglycerides that had significant contents of docosahexaenoic acid and eicosapentaenoic acid. Assays for amino acid profiles and mineral content of the precipitant layers were performed and supported the use of these materials as feed ingredients. The potential exists to use the supernatant fraction of the salmon eye digests as a specialized feed supplement due to the high content of long chain '3 fatty acids. Also, the potential exists for using the salmon brain precipitant fraction in diets for animals that can benefit from the high phospholipid content and amino acid profile.

Technical Abstract: Potential feed ingredients with high lipid content were made by enzymatic digestion followed by centrifugation of eye tissue from dusky rockfish (Sebastes ciliatos), coho salmon (Oncorhynchus kisutch), and sockeye salmon (Oncorhynchus nerka) and brain tissue from sockeye salmon. Materials with high levels of '3 fatty acids were made from pepsin digestion of sockeye and coho salmon eyes and brain tissues. After digestion, the sockeye and coho salmon eye dried supernatant fractions were 50% lipid or greater and the docosahexaenoic acid (DHA) content was 8.5% and 14% of total fatty acids and and eicosapentaenoic acid (EPA) content was 9.2% and 9.0%, respectively. Lipids from digested eye tissue were predominately triacylglycerides; whereas, lipid from digested brain tissue remained in the precipitant layer and consisted predominantly of phospholipids and sterols. The potential exists to use the supernatant fraction of the salmon eye digests as a specialized feed supplement due to the high content of long chain '3 fatty acids. Also, the potential exists for using the salmon brain precipitant fraction in diets for animals that can benefit from the high phospholipid content and amino acid profile. Use of different enzymes could produce different results with perhaps higher yields of certain fatty acids or increased amounts of phospholipids.