Changes in Tissue Lipid and Fatty Acid Composition of Farmed Rainbow Trout in Response to Dietary Camelina Oil as a Replacement of Fish Oil

Abstract

Camelina oil (CO) replaced 50 and 100 % of fish oil (FO) in diets for farmed rainbow trout (initial weight 44 ± 3 g fish(-1)). The oilseed is particularly unique due to its high lipid content (40 %) and high amount of 18:3n-3 (α-linolenic acid, ALA) (30 %). Replacing 100 % of fish oil with camelina oil did not negatively affect growth of rainbow trout after a 12-week feeding trial (FO = 168 ± 32 g fish(-1); CO = 184 ± 35 g fish(-1)). Lipid and fatty acid profiles of muscle, viscera and skin were significantly affected by the addition of CO after 12 weeks of feeding. However, final 22:6n-3 [docosahexaenoic acid (DHA)] and 20:5n-3 [eicosapentaenoic acid (EPA)] amounts (563 mg) in a 75 g fillet (1 serving) were enough to satisfy daily DHA and EPA requirements (250 mg) set by the World Health Organization. Other health benefits include lower SFA and higher MUFA in filets fed CO versus FO. Compound-specific stable isotope analysis (CSIA) confirmed that the δ(13)C isotopic signature of DHA in CO fed trout shifted significantly compared to DHA in FO fed trout. The shift in DHA δ(13)C indicates mixing of a terrestrial isotopic signature compared to the isotopic signature of DHA in fish oil-fed tissue. These results suggest that ~27 % of DHA was synthesized from the terrestrial and isotopically lighter ALA in the CO diet rather than incorporation of DHA from fish meal in the CO diet. This was the first study to use CSIA in a feeding experiment to demonstrate synthesis of DHA in fish.

Atlantic salmon (Salmo salar) liver transcriptome response to diets containing Camelina sativa products

“…CO-containing diets have been used in studies involving Atlantic cod (Gadus morhua) (Morais et al, 2012a;Hixson et al, 2013;Booman et al, 2014;Hixson and Parrish, 2014;Xue et al, 2014), Atlantic salmon Leaver et al, 2011;Morais et al, 2011b;Hixson et al, 2014b), and rainbow trout (Oncorhynchus mykiss) (Hixson et al, 2014a). Previously in Atlantic salmon, CO was included in blends (20% CO) with other plant-based oils to study the effect of substituting FO with vegetable oil blends on growth , ω3 LC-PUFA deposition in the flesh (Leaver et al, 2011), and cholesterol and lipoprotein metabolism (Morais et al, 2011b).…”

Interactive effects of dietary protein level and oil source on proximate composition and fatty acid composition in common carp (Cyprinus carpio L.)

“…Replacement of FO with VO should be such that the catabolism of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) is minimised and excess deposition of linoleic acid (LA) avoided (Thanuthong et al, 2011). Furthermore, reductions of EPA and DHA in fish muscle may affect the retention of oil in tissue adipocytes and, consequently, its physicochemical properties during storage and processing, influencing the quality of the final product (Hixson et al, 2014).…”

Fatty acid stable isotope signatures of molluscs exposed to finfish farming outputs

“…For example, the δ 13 C of 22:6n-3 of mussels at the closest sampling point within the farm's vicinity (at 75 m: −26.1 ‰) and the furthest point sampled away from the farm (at 2400 m: −22.2 ‰) coincides with the more depleted δ 13 C of 22:6n-3 in the feed (−23.8 ‰; see Table S4 in the Supplement) and the more enriched δ C-depleted isotopic signature compared to marinebased ingredients (e.g. Hixson et al 2014). …”