Publisher: Nofima AS
Number of pages: 37
International Standard Numbers:
Open Access: green
An important goal of this project was to study the potential to influence EPA and DHA levels in muscle in harvest size fish by feeding different levels of EPA and DHA in early life stages; before smoltification and after smoltification respectively. The hypothesis is that nutritional programming in early life stages may affect lipid metabolism in later stages of life.
Our study showed that the start feeding period (up to 40 grams) did not give significant effect on fatty acid composition of salmon fillets when the fish reached 4 kg. Feeding during the period from smoltification to 400 grams, however, had a significant effect on the levels of EPA and DHA in fillets after 13 months at sea and 3.5 kg increase in fish body weight.
Two other goals was to identify any long-term effects between High and Low desaturase families on fat deposition, EPA and DHA levels in fillets, quality and selected health markers. Our data shows that genetic background of the fish had significant effect on fat distribution in fish body, with particular importance for the development of fatty liver and distribution of fat between internal organs and muscle. High desaturase group showed higher capacity to EPA and DHA synthesis in early life stages, lower incidence of fatty liver and more fat distributed to muscle compared with Low desaturase group. The genetic pre-disposition to higher capacity to EPA and DHA synthesis in High desaturase family compared with Low desaturase family, seems to disappear when diets with high levels of plant oil was used in the growth phase in the sea. Due to the higher fat level in muscle in High desaturase group, the level of EPA + DHA in grams per 100 grams of muscle was significantly higher in this group than in Low desaturase group. The High desaturase group had significantly lower mortality after seawater transfer. There were no differences in muscle quality between the genetic groups in harvest size fish.