Abstract

The increasing global demand for fish oil and the unpredictability of its production will require the use of vegetable oils in commercial aquafeeds. However, only limited information is available on the impact of dietary inclusion of vegetable oils on product quality of farmed Atlantic cod. The fish examined were farmed Atlantic cod (Gadus morhua L) kept in 125m3 net pens at AKVAFORSK research station, Averøy. During the period August to October 2004, the cod (initial body weight 2 kg) were fed extruded dry pellets manufactured by Dana Feed AS. The diets contained 74% fishmeal, 14% wheat, 5% wheat gluten, and 6% oil. The oil added was either Peruvian anchovy oil (FO) or soybean oil (SO). Analyses were performed of raw cod fillets immediately after filleting (5 days post mortem) and after keeping the fillets frozen for three months at -25C. Furthermore, sensory analyses of heat-treated cod flesh were carried out after frozen storage (six and twelve months at –20°C). The growth rate was similar of the FO and SO group. Lipids of the cod muscle (~1% ww) consisted of 72 – 78% phospholipids, 5 – 9% triacylglycerols, and 17 – 19% free fatty acids. No significant difference was found in lipid class composition due to dietary treatment. The fatty acid profile in muscle of cod fed the SO diet changed significantly, where especially 18:2n-6 showed a linear increase during the feeding period. The dry matter content tended to be higher in fresh fillets of the FO group, and after frozen storage the difference between the dietary fish groups was significant. Liquid leakage from the muscle during three days of cold storage (2C) did not differ significantly between the fish groups. The SO group had lower fillet gaping after frozen storage and firmness tended to be higher in fresh fillets. No off-odour was detected immediately after filleting, but after frozen storage the raw fillets from the SO group tended to have higher values for off-odour. Sensory analyses after heat treatment, as evaluated by a consumer panel, showed no significant difference between the fish groups. The fatty acid profile in fillets was significantly altered in cod fed diets supplemented with soybean oil, but important product quality characteristics such of texture, colour, water holding capacity and taste were not negatively affected

Keywords

Atlantic cod; soybean oil; fatty acid composition; quality; storage

Published in

Title: Proceedings

Conference

XII International Symposium on Fish Nutrition & Feeding

SLU Authors

• Pickova, Jana

  • Department of Molecular Sciences, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Food Science
Fish and Aquacultural Science


Permanent link to this page (URI)

https://res.slu.se/id/publ/10376