New feed guid­ance for sal­mon

Fish Farmer - - News -

THE Nor­we­gian In­sti­tute of Fish­eries and Seafood Re­search (NIFES) has pro­duced new rec­om­men­da­tions for the vi­ta­min and min­eral sup­ple­ments in the feed for At­lantic sal­mon.

It says this is nec­es­sary be­cause of a shift from mainly ma­rine in­gre­di­ents to feeds where more than 70 per cent comes from plants.

For the past six years NIFES has been tak­ing part in an EU project called Ar­raina, the goal of which is to find out how much mi­cronu­tri­ents dif­fer­ent species of fish need now that the com­po­si­tion of the feed has changed.

Nor­way and Scot­land have col­lab­o­rated on the part of the project that con­cerns sal­mon. It turns out that, for some of the vi­ta­mins and min­er­als stud­ied so far, the old rec­om­men­da­tions are far from what the fish ac­tu­ally need.

‘When we first saw the re­sults, we could hardly be­lieve our

eyes,’ said Kristin Hamre, senior sci­en­tist at NIFES.

‘For ex­am­ple, when the re­sults for the B vi­ta­min niacin came in, it turned out that sal­mon needs four times as much niacin as pre­vi­ously rec­om­mended, and twice as much vi­ta­min B6.’

The old rec­om­men­da­tions for mi­cronu­tri­ents in feed were the re­sult of tri­als con­ducted in the 1980s. The tri­als were largely per­formed on rain­bow trout ju­ve­niles, and very few stud­ies looked at sal­mon and adult fish.

‘Im­ple­men­ta­tion of this new knowl­edge is im­por­tant for the growth and wel­fare of the sal­mon,’ said Hamre.

‘Lack of mi­cronu­tri­ents can be fa­tal for the fish. Too lit­tle of just one nu­tri­ent is enough to cause prob­lems.’

She ex­plained that farmed sal­mon feed has changed dra­mat­i­cally in the last 10 to 15 years. Plants con­tain anti-nu­tri­ents that can cause the fish to ab­sorb less of the nu­tri­ents in the feed, and in some cases the sal­mon there­fore need dif­fer­ent quan­ti­ties of vi­ta­mins and min­er­als.

Hamre added: ‘Even if the plants con­tain th­ese nu­tri­ents, the fish are un­able to ab­sorb them to the same ex­tent as they would from ma­rine feeds.

‘Plant in­gre­di­ents also con­tain lower lev­els of some nu­tri­ents than fish­meal and fish oil do. That is why we need to ad­just the amount of mi­cronu­tri­ents.’

Through the Ar­raina project, NIFES sci­en­tists have now cre­ated nu­tri­ent pack­ages of all the mi­cronu­tri­ents, which they have added in graded lev­els to the feed.

In a sep­a­rate study, the Nor­we­gian Food In­spec­torate has sub­mit­ted sam­ples of Nor­we­gian pro­duced sal­mon for lab­o­ra­tory anal­y­sis and the re­sults show that the omega-3 level in farmed sal­mon has de­creased over the past 10 years, be­cause large parts of to­day’s sal­mon feed are plant and not fish based.

Kristin Hamre Above:

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