Unidentified growth promoters in marine raw materials?

New information about the differences between marine and vegetable protein sources used in aquafeed
November 8, 2006

Unidentified growth promoters in marine raw materials?

New information about the differences between marine and vegetable protein sources used in aquafeed will be revealed at Aquafeed Horizons Conference. The impact of small water soluble components in growth experiments with trout and cod will be discussed.

In the work to find replacements for fish meal in feed for fish, it is essential to know what nutrients are really being replaced. To date the majority of research has been focused on protein quality, essential amino acids and lipids. However, protein sources also vary widely in other nitrogen containing components or nutrients that may also affect fish growth and performance. Some of these components include taurine, anserine, nucleotides and free amino acids, which may vary widely in marine resources compared to plant protein sources.

To date, marine ingredients cannot be totally replaced by vegetable protein sources without significant reduction in growth performance or feed efficiency for most fish species investigated. This is also the case when experimental diets are equalled in limiting amino acids and minerals and the levels of growth inhibitors in plant sources are reduced. It is therefore possible that other components that is present in fishmeal and absent in plant protein, also are important for the growth results.
Feed ingredients from marine resources and plants are different in compounds other than the macro nutrients, and there is increasing evidence that these compounds may be important in the evaluation of feed ingredients.

As part of the SEAFOODplus project, some 40 different feed ingredients were screened for the presence of 30 or so different nitrogen extractable compounds. The various ingredients tested were mainly sampled from a commercial feed producer.

Senior Scientist Dr. Anders Aksnes, Fiskeriforskning, Bergen, Norway, will reveal data for the content of extractable compounds in feed ingredients at Aquafeed Horizons Conference.

The possible impact of these components in fish feed was tested in feeding experiments with fish. Growth experiments with rainbow trout and cod indicate that small marine compounds present in marine raw materials affect both growth and feed efficiency. This is important in the discussion of replacing fish meal with vegetable protein sources in feed for fish.

Dr. Anders Aksnes is a biochemist and nutritionist from the University of Bergen, Norway. He has many years experience in research for feed development and biological performance. His main focus of research has been within marine biotechnology, raw materials, feed ingredients, digestibility of nutrients and growth experiments. Aksnes has also developed and commercialized new feed concepts for fish and shrimp larvae for use in very early stages.

Aquafeed Horizons is organized and presented by, the aquafeed industry information gateway and Fiskeriforskning, the Norwegian Institute of Fisheries and Aquaculture Research.

Aquafeed Horizons will take place at the Jaarbeurs, Utrecht, the Netherlands,
May 9-10, 2007. More information, including program details, can be found on the conference website: or email:

For more about Fiskeriforskning Department of Aquafeed Development and Marine Processing, contact Department head, Ola Fleskland: or visit

Information on Victam International 2007 is available at: