Introductory studies based on an ongoing research-directed project in AKVAFORSK have revealed critical energy demanding periods for 1+ and 0+ salmon in sea coinciding with negative effects on growth, feed conversion and natural outbreak of virus diseases (IPN/HSMB). Dietary supplementation of bioactive fatty acids was shown significantly to increase fat oxidation capacity, reduce osmotic stress and reduce mortality to 1/3 during a natural outbreak of IPN in sea (2.8% vs. 7.8% in the control). Hence, since vaccination still seems far from solving the IPN-problem in practical salmon farming, dietary supplementation of bioactive fatty acids by improving the energy access in energy demanding periods showed promising results.
Before employing these findin gs in practical diets for the farming industry, more details concerning doses, treatment period and metabolic effect are required. Therefore, the main objective of the present project is to obtain knowledge that makes it possible to optimise the use of bi oactive fatty acids in feed for farmed Atlantic salmon so as to increase growth, feed conversion and its resistance to viral infections. In addition to gaining practical results of importance in the production of fish feed, the results obtained will add t o the steadily increasing knowledge of bioactive fatty acids in fish, being an important topic in human medicine.