Submitted to: Aquaculture Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/19/2010
Publication Date: 4/20/2011
Citation: Stone, D.A., Oliveira, A.C., Ross, C.F., Plante, S., Smiley, S., Bechtel, P.J., Hardy, R.H. 2011. The effects of phase-feeding rainbow trout (Oncorhynchus mykiss) with canola oil and Alaskan pollock fish oil on fillet fatty acid composition and sensory attributes. Aquaculture Nutrition. 17(2):e521-e529. Interpretive Summary: Rainbow trout may be produced using canola oil or pollock oil as primary lipid sources without effecting growth performance and fillet yield. Phase feeding using canola oil and pollock oil was a successful management tool that could be utilized to attain a more healthful product with respect to EPA and DHA level and a desirable ratio of total omega-3 fatty acids (FA) to total omega-6 FA. The phase feeding strategy would also be beneficial in reducing diet costs in today’s market where fish oil prices have been elevated to all time highs. The use of pollock oil in place of menhaden oil led to enhanced levels of EPA and DHA as well as superior ratios of total omega-3 FA to total omega-6 FA. Additionally, the sensory attributes of fish fed pollock oil were not perceivable different to those of fish fed menhaden oil; however, panelists preferred the canola oil treatment. With respect to comparisons with wild fish, the cultured fish provided higher levels of EPA and DHA, while at the same time maintained ratios of total omega-3 FA to total omega-6 FA that exceeded those recommended for human health.
Technical Abstract: Rainbow trout (186g) were fed three test diets where the lipid source (15%) was either menhaden oil (MO), pollock oil (PO) or canola oil (CO) for eight weeks to an 27 average weight of 370g. The CO group was then divided into two groups, one continuing on the CO diet and the other switched to the PO diet (CO¬PO). After nine additional weeks of feeding, the average fish weight approximately doubled (719¬749g). No significant differences were found in average final weigh or fillet yield among dietary treatment groups. Fatty acid profiles of fillets from trout fed MO, PO or CO supplemented diets reflected the fatty acid profiles of the added oils whereas the fatty acid profile of fillet from trout in the CO¬PO group exhibited values similar to those of fish fed PO. The ratio of '3/'6 FA was nearly 2.5 times higher in fillets from the CO¬PO group compared to the CO group. Sensory analysis showed that panelists preferred CO fed fillets over those fed MO, PO, or CO¬PO. Phase¬feeding CO and PO reduced fish oil use and resulted in fillets with double the content of EPA and DHA over CO¬fed fish, similar to levels in MO¬fed fish.