When we keep fish in aquaculture, we must be sure that the fish receive the nutrients they require for growth and good health. Scientists at Nofima have studied nutrition in aquatic animals for several decades.
- Feed studies with salmon in all stages of the life cycle
- Feed studies with most marine species in aquaculture
- Production of feed for studies with all types of ingredient and raw material
- Development and evaluation of raw materials from new sources
- Analysis of feed for nutrients and foreign ingredients
Fish meal and fish oil have been the traditional starting points for good fish feed, because they contain the nutrients that fish need. Access to fish meal and fish oil has become more difficult during the past 15 years due to the growth of the aquaculture industry, so the fraction of other ingredients that satisfy the nutritional needs of fish in aquaculture has increased. Approximately 70% of the raw materials in salmon feed is now obtained from plants. Further, krill and some yeast strains are other examples of raw materials that contain beneficial nutrients.
It has become clear that plant proteins can replace fish meal, since raw materials from the plant kingdom contain sufficient amounts of the important amino acids, which are the building blocks of proteins. Fish (as other animals) break down the proteins in the feed to amino acids, and then use these to build the proteins that the particular species needs. Salmon from aquaculture is today a net producer of fish proteins. This means that it contributes more fish protein to our diet than it consumes in its own feed.
Salmon need the long marine omega-3 fatty acids, of which large amounts are found in fish oil, in the diet. Plant oils contain higher amounts of other fatty acids that cannot immediately be converted to these long marine omega-3 fatty acids. Nofima has studied the fat metabolism of salmon extensively, and is a world-leader in work to understand how the fat in feed influences growth and health.
Feed contains also substances known as “micronutrients”. This term refers to vitamins, minerals and other substances that are present in feed and raw materials in small amounts. Not all raw materials contain the same micronutrients, and the amounts vary depending on the nature of the raw materials. Fish meal, for example, contains considerable amounts of iodine, selenium and vitamin A. Soya protein concentrate, in contrast, is a poor source of these micronutrients. Against the background of work carried out at Nofima, feed can now be fortified with certain nutrients such that the salmon receive everything they require. Modern salmon feed has become what we call “balanced”.
Those active in the aquaculture industry can provide the fish with correct nutrition and in this way contribute to producing fish that resist disease and stress. The salmon produced in modern aquaculture have a rapid rate of growth and must therefore receive sufficient amounts of the correct feed at the right time. Nofima is working to identify how the increased addition of certain nutrients can improve fish health. We see, for example, that adding phosphorus and zinc to the feed that is used early in the life cycle can prevent the development of bone deformities.
Sustainable development of the aquaculture industry is a necessary condition for its growth. The ingredients of feed play a role in this regard. Raw materials are currently imported mainly from South America and Europe. It is conceivable that the proteins and oil to be used in fish feed can be produced from sources that are closer to Norway, and that require less land area and a lower use of pesticides. The feed industry depends on access to various raw materials with the correct nutrients.
Nofima is working, in collaboration with other research environments, on the use of algae, tare, rest raw materials (from the production of other animals) and tunicates in fish feed.