Replacing Fish Oil With Flaxseed on Nutritive Value of Rainbow Trout
This study evaluated the suitability of flaxseed oil as a source of supplemental dietary lipid for fingerlings of rainbow trout. Triplicate groups of the 30 fingerlings held under identical culture conditions were fed twice daily by iso-nitrogenous, iso-calorific and iso-lipidic diets for 8 weeks. Experimental diets consisted of 30.3% protein, 18.7 kJg-1 energy and 16.7% lipid from fish oil (FO), flaxseed oil (FxO) and 1:1 blends of the two oils (FFxO). Whole body fatty acid compositions mirrored those of diet treatments. Highest amounts of HUFAs was detected in fish fed 100% FO, which was significantly different from other treatments. In all treatments PUFAs/SFAs and n-6/n-3 ratios were higher than 0.45 and lower than 4, respectively. Present results indicate the fingerlings can be reared on diets in which FO has been replaced with FxO, with no significant effects on nutritive value of fish for human consumption.