Growth and fatty acid composition of two strains of Arctic charr (Salvelinus alpinus) on diets formulated with low fish oil inclusion in a recirculating aquaculture system

Authors: Burr, Gary; Wolters, William; Barrows, Frederic

Submitted to: North American Journal of Aquaculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/13/2016
Publication Date: 6/24/2016
Citation: Burr, G.S., Wolters, W.R., Barrows, F. 2016. Growth and fatty acid composition of two strains of Arctic charr (Salvelinus alpinus) on diets formulated with low fish oil inclusion in a recirculating aquaculture system. North American Journal of Aquaculture. 78:270-278.

Interpretive Summary: Arctic charr is a highly desirable species to produce due to their fast growth, culture conditions and reputation as a sustainable cultured fish due to closed containment culture. A study was conducted to evaluate two Arctic charr stocks performance and highly unsaturated fatty acid retention fed one of three diets; one diet containing 11% fish oil and 11% soy/canola, one diet containing 5% fish oil and 18% canola oil and one diet containing 5% fish oil and 18% poultry fat. These oils were chosen due to their use in commercial feeds. After a 250 day growth period, the fish from the USDA stock had significantly higher (41%) average weight compared to the commercial stock. The fillet yield did not vary among diets or stocks with an average yield of 67.4% of the gutted weight. The fatty acid profiles did not vary among strains, but were affected by the diet. Fish fed higher levels of omega-3 fatty acids in their diet had higher levels in their fillets. Additional research is needed to lower the amount of fish oil in the diet while maintaining the omega-3 levels in the fillet.

Technical Abstract: Arctic charr (Salvelinus alpinus) is a highly desirable species to culture due to their fast growth, culture conditions and reputation as a sustainably produced fish due to closed containment culture. A study was conducted to evaluate two Arctic charr stocks (one commercial stock and one from the USDA) performance and highly unsaturated fatty acid (HUFA) retention fed one of three diets; one diet containing 11% fish oil and 11% soy/canola(Diet 1, crude lipid 27%), one diet containing 5% fish oil and 18% canola oil (Diet 2, crude lipid 27%) and one diet containing 5% fish oil and 17 poultry oil (Diet 3, crude lipid 27%). The protein sources did not vary among the diets and the reference diet lipids were similar to commercial grower diets. Seven hundred sixty-eight Arctic charr (initial weight 314.6 ± 2.5 g S.E.) were stocked into twelve 2-m3 tanks. Brackish water (2g/L) was supplied to the tanks at 20 lpm with oxygen. Fish in quadruplet tanks were fed one of the three diets. After 250 days, the fish from the USDA stock (1736g) had significantly higher average weight, approximately 510 g greater, compared to the commercial stock (1226g). Average weight gain was not significantly different among the diets but tended to be higher in diet 2 (p = 0.09), and the USDA stock (~1409 g gained) had higher average weight gain compared to the commercial strain (~924 g gained). Specific growth rate (SGR) was significantly different among the diets with diet 2 having the highest growth rate (0.62 % day-1 compared to 0.59% day-1, 0.58% day-1 ) and the USDA stock having a significantly higher SGR compared to the commercial strain (0.65% day-1 compared to 0.54% day-1). Fillet yield did not vary among diets or stocks with an average yield of 67.4% of the gutted weight and 62.2% of the total weight. Fillet color and fillet fatty acid profiles are being evaluated.