RESULTS

1. RESULTS REFERENCES ABSTRACT OBJECTIVES CONCLUSION INTRODUCTION MATERIALS AND METHODS Omega-3 Fatty Acid and Total Fat Contents in Omega-3-enhanced Farmed Rainbow Trout (Oncorhynchus mykiss) Y. C. Chen, J. Nguyen, K. Semmens, S. Beamer, and J. Jaczynski West Virginia University, Animal & Veterinary Sciences This study was designed to investigate the effects of flaxseed oil (FO) supplementation on ω-3 FA and fat contents of trout fillets. The experiment was a completely randomized design. A commercial trout diet was supplemented with 0 (control), 8.5% (w/w), or 15% (w/w) of FO. Trout were harvested on days 0, 30, 60, 90, and 120. Trout were filleted to obtain boneless, skinless butterfly fillets. The moisture and total fat contents, as well as fatty acid profile (FAP) were determined. The data were analyzed statistically using ANOVA. While the total fat levels of fillets were not affected by FO supplementation, the FAP was. The lowest (P<0.05) proportion of saturated fatty acids was obtained in 15.0% FO group, followed by 8.5% FO group and control group. The opposite results were observed in the unsaturated fatty acid. The highest ω-3 FA content in fillets was determined in the 15% of FO supplementation group, followed by the 8.5% of FO supplementation group and the control group. While the 15 and 8.5% of FO supplementation increased concentration of α-LNA in fillets, the EPA and DHA contents decreased (P<0.05). Our results indicate that the omega-3-enhanced trout can be raised by supplementing fish diets with FO. We also conducted a storage stability study and human clinical trials using the developed omega-3-enhanced trout fillets. The overall objective was to develop omega-3 fortified trout that would allow WV aquaculture industry to market trout food products as functional foods with health benefits superior to other trout or equal to salmon. Table1. Fat (%) of trout fillets as affected by feed supplementation with flaxseed oil Table 2. Fatty acid profile in trout fillets as affected by feed supplementation with flaxseed oil FO: flaxseed oil No differences were observed between the groups within a row (P>0.05) Omega-3 polyunsaturated fatty acids (-3 PUFA) in farmed rainbow trout fillets are lower than wild trout’s fillets.In 2002, the Food and Drug Administration (FDA) approved health claim that omega-3 polyunsaturated fatty acids (-3 PUFA), mainly eicosapentaenoic (EPA, 20:5-3) and docosahexaenoic (DHA, 22:6-3) reduce risk of cardiovascular disease (CVD), giving a marketing leverage for functional foods fortified with the -3 PUFA. Functional foods resemble traditional foods, but render benefits beyond their nutrition by preventing diseases and promoting health. Castell and others (1972) showed that dietary linoleic (18:2-6) and linolenic (18:3-3) fatty acids increased the concentration of these fatty acid and that of the EPA and DHA in the muscle tissue. Green and Selivonchick (1990) suggested that trout maintained concentration of the EPA (20:5-3) and DHA (22:6-3) at physiologically optimum level. Fish synthesize the -3 PUFA from shorter-chain essential fatty acids (EFA), linoleic (18:2-6) and linolenic (18:3-3) by their elongation and de-saturation (Nawar 1996). Therefore, an opportunity exists to fortify trout fillets with -3 PUFA by dietary modification. Flaxseed oil contains the highest concentration of α-linolenic acid (ALA) compared to other lipid sources used in fish feeds. Our hypothesis is that supplementing fish diet containing high concentration of FO will increase -3 PUFA contents in farmed rainbow trout fillets. • Regardless of feeding period, total fat level (%) in trout fillets was not (P>0.05) affected by supplementing trout basal diet with flaxseed oil. • The level of saturated fatty acids in trout fillets decreased with supplementing trout with flaxseed oil after 30 days of feeding. • Simultaneously, the level of unsaturated fatty acids in trout fillets increased in flaxseed oil feeding groups after 30 days of feeding. • The highest (P<0.05) concentration of omega-3 fatty acids in fillets was measured in 15.0% FO group, followed by 8.5% FO group, and control group. • The increased concentration of total omega-3 fatty acids in the 15 and 8.5% FO groups was due to the increased (P<0.05)concentration of ALA in these two groups. • Lower (P<0.05) concentrations of EPA and DHA were measured in fish filletssupplemented with FO. It might be due to the deposition of the ALA in the muscle and minimal elongation and de-saturation of ALA to form EPA and DHA by Rainbow trout. • FO: flaxseed oil • Test parameters: total fat content, fatty acid profile. FO: flaxseed oil; ALA: alpha-linolenic acid; EPA: Eicosapentaenoic acid; DHA: Docosahexaenoic acid Castell JD, Lee DJ, Sinnhuber RO. 1972. Essential fatty acids in the diet of rainbow trout (Salmo gairdneri), lipid metabolism and fatty acid composition. J Nutr 102:93-100. Green DHS, Selivonchick DP. 1990. Effects of dietary vegetable, animal and marine lipids on muscle lipid and hematology of rainbow trout (Oncorhynchus mykiss). Aquaculture 89:165-182.