Growth and Fatty Acid Composition of Two Strains of Arctic Char Fed Diets Formulated with Low Fish Oil Inclusion in a Recirculating Aquaculture System.

Arctic CharSalvelinus alpinusis a highly desirable species for aquaculture due to their fast growth, culture conditions, and reputation as a sustainably produced fish as a result of closed containment culture. A study was conducted to evaluate performance and highly unsaturated fatty acid retention in two Arctic Char stocks—one commercial stock and one from the U.S. Department of Agriculture (USDA)—fed one of three diets containing different lipids (27% total): 11% fish oil and 11% soy–canola (diet 1, reference diet), 5% fish oil and 18% canola oil (diet 2), and 5% fish oil and 17% poultry oil (diet 3). Protein sources did not vary among the diets, and the lipid sources for the reference diet were similar to those included in commercial grower diets. After 250 d, fish from the USDA stock (1,736 ± 28 g [mean ± SE]) had significantly higher average weight, approximately 510 g greater, compared with the commercial stock (1,226 ± 19 g). 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 (~1,409 ± 27 g gained) had higher average weight gain compared with the commercial stock (~924 ± 18 g gained). Specific growth rate (SGR) was significantly different among the diets; fish fed diet 2 had the highest growth rate (0.62%/d compared with 0.59%/d and 0.58%/d for the other two diets) and the USDA stock had a significantly higher SGR compared with the commercial stock (0.65 ± 0.01%/d compared with 0.54 ± 0.01%/d). Fillet yield did not vary among diets or stocks. The average fillet yield was 67.4% of the gutted weight and 62.2% of the total weight. Selected fatty acid profiles did vary by stock and all fatty acid profiles showed dietary effects. The USDA stock had superior growth, and diet had the greatest influence on the fatty acid profile of the fillets. Received September 25, 2015; accepted February 13, 2016 Published online June 24, 2016 [ABSTRACT FROM PUBLISHER]