Archive Institutionnelle de l’Ifremer Total replacement of fish oil by soybean or linseed oil with a return to fish oil in

• Main Author: Turbot (psetta Maxima
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2003
• Subjects: Turbot
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.335.1679; http://archimer.ifremer.fr/doc/2003/publication-375.pdf

The aim of the study was to investigate the replacement of fish oil by vegetable oils and the effects of a washout with a return to fish oil on growth performances and lipid metabolism. Three experimental fish meal based, isonitrogenous (crude protein content: 57.5%) and isolipidic (crude lipid content: 16.5%) diets, were formulated containing either 9 % of added fish oil (FO), soybean oil (SO) or linseed oil (LO). Each diet was distributed to triplicate groups of 25 marketable size turbot (initial body weight of 579 g) grown in seawater at a water temperature of 17°C. Fish were fed once a day to visual satiety. At the end of the growth trial which lasted 13 weeks, all groups of turbot were fed FO diet for 8 weeks. The growth of turbot was high, but the incorporation of vegetable oils in the diets resulted in a slight decrease in growth as compared to those fed the fish oil based diet. Feed and protein efficiency and whole body composition were not affected by dietary lipid sources. Total lipid content was low in the muscle of turbot (below 2%), ventral muscle being fatter than dorsal muscle. Liver and muscle fatty acid (FA) composition reflected dietary FA composition. Liver and muscle of fish fed SO diet were rich in 18:2n-6 whereas those of fish fed LO diet were rich in 18:3n-3. Liver and muscle of fish fed SO and LO diets had lower levels of 20:5n-3 and 22:6n-3 in comparison to those of fish fed FO diet. In turbot, hepatic lipogenic enzyme activities were low and not influenced by dietary lipid source. At the end of