Use of canola oil in winter feed for salmon in the sea / Use of canola oil in winterdiets for Atlantic salmon
An experiment was performed with different amounts of rapeseed oil (0, 50 and 80%) in winter feed for 570 grams of salmon raised in the sea with 28.2 ‰ salt (26 - 34 ‰) at an average temperature of 4.5˚C (3.8 - 5 , 6˚C). The fish doubled in weight during the 152-day trial period. TGC3 was an average of 2.9. The fat content of the feed had very little effect on the growth, feed intake, feed utilization and volume content of fish fillets. The composition of the feed fat did not have much effect on the color of the fillets, although fish that were fed only fish oil gave significantly (p = 0.017) lighter fillets than fish that were fed with rapeseed oil. The type of fat in the feed, however, had a significant effect on the fatty acid composition of the fat in both the feed and the fat in the fillets, especially the EPA, DHA content and the ratio of n-6 and n-3 fatty acids. However, the results show that the effect in the fillet fat is much smaller than in the feed fat, especially with the fatty acid DHA. It seems that DHA converts feed fat into fillet fat rather than using it as an energy source.
An experiment with different inclusion of Canola oil (0, 50 and 80%) in diets for 570 grams Atlantic salmon that was reared in sea water with average salinity of 28.2 ‰ (26 - 34 ‰) at average temperature of 4.5˚ C (3.8 - 5.6˚C). The fish doubled its weight during the 152 days trial period. TGC3 was on average 2.9. The fat type had had only minor effects on growth, feed intake, feed conversion and nutrient content in filet. The fat type in the diet did not have much effect on the filet color even though the fish that got feed with fish oil was significantly (p = 0.017) lighter in filet color than fish that got diets with Canola oil. Composition of the diets had market effect on the fatty acid composition of both dietary fat and filet fat in particular the content of EPA and DHA and the n ‐ 6 to n ‐ 3 ratio. However the results show lower effect in the filet fat than in the dietary fat, particularly regarding the content of DHA indicating that the fish is directing that fatty acid towards the storage lipid in the filet rather than using it as energy source.