Restoration of EPA and DHA in rainbow trout (Oncorhynchus mykiss) using a finishing fish oil diet at two different water temperatures

Feeding fish a fish oil finishing diet (FOFD) after grow-out on vegetable oil diet is one strategy to restore eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) levels. We investigated restoration of EPA and DHA in rainbow trout fed a FOFD preceded by a grow-out period on 50% or 75% palm fatty acid distillate (PFAD) diets at optimal (15 Celsius degree) or elevated (20 Celsius degree) water temperatures. Using the FOFD restored EPA and DHA in fillet and whole carcass of fish previously fed either 50% PFAD diet from 85% to 98% or 75% PFAD from 66% to 93% of values obtained for fish fed FO diet throughout. Water temperature did not influence EPA and DHA restoration. Growing rainbow trout with diets where FO was replaced by either 50% or 75% PFAD followed by a FOFD reduced FO usage by around 30% and 44% at 15 Celsius degree, respectively, and 32% and 48% at 20 Celsius degree, respectively. Miller, M. R., Nichols, P. D., & Carter, C. G. (2008). n3 Oil sources for use in aquaculture - Alternatives to the unsustainable harvest of wild fish. Nutrition Research Reviews, 21, 85-96. Montero, D., Robaina, L., Caballero, R., Gine s, R., & Izquierdo, M. S. (2005). Growth, feed utilization and flesh quality of European sea bass (Dicentrarchus labrax) fed diets containing vegetable oils: a time-course study on the effect of a re-feeding period with a 100% fish oil diet. Aquaculture, 248, 121-134. Naylor, R. L., Hardy, R. W., Bureau, D. P., Chiu, A., Elliott, M., Farrell, A. P., et al. (2009). Feeding aquaculture in an era of finite resources. Proceedings of the National Academy of Sciences, 106, 15103-15110. Ng, W. K., Campbell, P. J., Dick, J. R., & Bell, J. G. (2003). Interactive effects of dietary palm oil concentration and water temperature on lipid digestibility in rainbow trout, Oncorhynchus mykiss. Lipids, 38, 1031-1038. Ng, W. K., Codabaccus, M. B., Carter, C. G., & Nichols, P. D. (2010). Replacing dietary fish oil with palm fatty acid distillate improves fatty acid utilization in rainbow trout, Oncorhynchus mykiss, maintained at optimal or elevated water temperature. Aquaculture, 309, 165-172. Ng, W. K., Sigholt, T., & Bell, J. G. (2004). The influence of environmental temperature on the apparent nutrient and fatty acid digestibility in Atlantic salmon (Salmo salar L.) fed finishing diets containing different blends of fish oil, rapeseed oil and palm oil. Aquaculture Research, 35, 1228-1237. Ng, W. K., Tocher, D. R., & Bell, J. G. (2007). The use of palm oil in aquaculture feeds for salmonid species. European Journal of Lipid Science and Technology, 109, 394-399. Robin, J. H., Regost, C., Arzel, J., & Kaushik, S. J. (2003). Fatty acid profile of fish following a change in dietary fatty acid source: Model of fatty acid composition with a dilution hypothesis. Aquaculture, 225, 283-293. Rosenlund, G., Obach, A., Sandberg, M. G., Standal, H., & Tveit, K. (2001). Effect of alternative lipid sources on long-term growth performance and quality of Atlantic salmon (Salmo salar L.,). Aquaculture Research, 32, 323-328. Seierstad, S. L., Seljeflot, I., Johansen, O., Hansen, R., Haugen, M., Rosenlund, G., et al. (2005). Dietary intake of differently fed salmon; the influence on markers of human atherosclerosis. European Journal of Clinical Investigation, 35, 52-59. Tacon, A. G. J., Hasan, M. R., & Subasinghe, R. P. (2006). Use of fishery resources as feed inputs to aquaculture development: trends and policy implications. FAO Fisheries Circular No. 1018 (p. 99). FAO Fisheries Department, Food and Agriculture Organization of the United Nations. Torstensen, B. E., Froyland, L., Ornsrud, R., & Lie, O. (2004). Tailoring of a cardioprotective muscle fatty acid composition of Atlantic salmon (Salmo salar) fed vegetable oils. Food Chemistry, 87, 567-580. Turchini, G. M., Francis, D. S., & De Silva, S. S. (2006). Modification of tissue fatty acid composition in Murray cod (Maccullochella peelii peelii, Mitchell) resulting from a shift from vegetable oil diets to a fish oil diet. Aquaculture Research, 37, 570-585. Turchini, G. M., Torstensen, B. E., & Ng, W. K. (2009). Fish oil replacement in finfish nutrition. Reviews in Aquaculture, 1, 10-57.