Use of ω3 rich oilseed Camelina (Camelina sativa) as a fish oil replacement in aquaculture feeds: implications for growth and lipid biochemistry of farmed Atlantic cod (Gadus morhua), Rainbow trout (Oncorhynchus mykiss) and Atlantic salmon (Salmo salar).

Hixson, Stefanie M. (2014) Use of ω3 rich oilseed Camelina (Camelina sativa) as a fish oil replacement in aquaculture feeds: implications for growth and lipid biochemistry of farmed Atlantic cod (Gadus morhua), Rainbow trout (Oncorhynchus mykiss) and Atlantic salmon (Salmo salar). Doctoral (PhD) thesis, Memorial University of Newfoundland.

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Abstract

Camelina oil (CO) is a potential lipid replacement for fish oil (FO) in aquaculture feeds due to its high lipid content (40%), high levels of α-linolenic acid (ALA, 18:3ω3) (30%), antioxidants, and low levels of saturated fatty acids. Five feeding experiments were conducted to determine the effectiveness of CO as a FO substitute for three farmed fish species relevant to Canadian aquaculture: Atlantic cod (Gadus morhua), rainbow trout (Oncorhynchus mykiss) and Atlantic salmon (Salmo salar). Three experiments were conducted with Atlantic cod. In the first experiment, a fish oil control (FO), 40% (CO40) and 80% (CO80) replacement of FO with CO were fed to cod for 9 weeks. There was no effect of replacing FO with CO on growth performance. The second study tested diets with 100% replacement of FO with CO (100CO), solvent extracted fish meal (100COSEFM) and partially substituted fish meal (FM) with 15% inclusion of camelina meal (CM) (100CO15CM) for 13 weeks. Cod fed CO had a lower final weight than cod fed FO, while cod fed 100CO15CM had a lower final weight than all other groups. Cod tissue lipid and fatty acid profiles were significantly affected by CO inclusion. In the third experiment, cod were unintentionally exposed to the parasite Loma morhua, which was a significant factor that affected growth in this experiment. In the rainbow trout experiment, CO replaced 50% and 100% of FO. Growth was not affected after the 12 week feeding trial. Tissue lipid and fatty acid profiles were significantly affected by the addition of CO. Compound-specific stable isotope analysis indicated that 27% of docosahexaenoic acid (DHA, 22:6ω3) was synthesized de novo from the CO diet. The Atlantic salmon study tested diets with 100% CO, SEFM and 10% inclusion of CM, in a 16 week feeding trial. Growth was not affected by using 100% CO; however, it was lower in groups fed SEFM and 10% CM diets. Total lipid in salmon flesh fed a diet with CO, SEFM and CM was significantly higher than FO. Amounts of DHA in salmon fed any CO diet were similar to FO-fed salmon due to increased flesh lipid. The sensory quality of salmon fillets was not affected by CO.

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