Monola oil versus canola oil as a fish oil replacer in rainbow trout feeds : effects on growth, fatty acid metabolism and final eating quality

Monola oil, a high oleic acid canola cultivar, and canola oil were evaluated as replacers of 26 fish oil at three levels of inclusion (60, 75 and 90%) in rainbow trout diets. After a 27-week 27 grow-out cycle, the diet-induced effects on growth, fatty acid metabolism and final eating 28 quality were assessed. Overall, no effects were noted for growth, feed utilisation or fish 29 biometry, and the fatty acid composition of fish fillets mirrored that of the diets. Dietary 30 treatments affected fillet lipid oxidation (free malondialdehyde), pigmentation and flavour 31 volatile compounds, but only minor effects on sensorial attributes were detected. 32 Ultimately, both oils were demonstrated to possess, to differing extents, suitable qualities 33 to adequately replace fish oil from the perspective of fish performance and final product 34 quality. However, further research is required to alleviate on-going issues associated with 35 the loss of health promoting attributes (n-3 long chain polyunsaturated fatty acids) of final 36 farmed products.