Nofima has Found New Sources of Omega-3 for Fish Feed

The demand for fish oil rich in omega-3 has long been\r\ngreater than the supply. Sources that can meet the requirement for omega-3 in\r\nthe diet of farmed fish have until now been scarce. However, new sources of\r\nomega-3 are partly on the market and research shows that these are safe to use\r\nin farmed salmon feed.

Nofima scientists have\r\ntested two new sources. One of them is canola oil extracted from a rapeseed\r\nplant which is genetically modified to produce the omega-3 fatty acids DHA and\r\nALA. The other is the microalgae Schizochytrium sp, which is not genetically modified\r\nbut naturally rich in DHA. These sources are partially available on a\r\ncommercial scale.

The results show that both of them provide good performance,\r\nquality, composition of fatty acids and health for the salmon.

Bente Ruyter has extensive experience regarding research on\r\nsources of omega-3 in salmon feed, and now sees that access to new sources is\r\nfully available

Why research sources\r\nof omega-3?

Both humans and fish require the long, marine omega-3 fatty\r\nacids EPA and DHA to maintain good health. What we receive from fish oil\r\nderived from wild fish is not enough to meet the needs of a growing population\r\nand aquaculture industry. Therefore, several sources of marine omega-3 are\r\nneeded. Some omega-3 is used in health food products, some in animal feed and a\r\nlarge proportion in feed for farmed fish. Omega-3 levels in Norwegian farmed\r\nsalmon have previously fallen and one now assumes that the lower limit has been\r\nreached. This trend can now be stopped by utilising new sources.

In the research project “New\r\nomega-3 sources in salmon feed”, the aim was to obtain scientific evidence\r\nregarding new feed sources and their effect on fish performance, quality and\r\nhealth. The project manager was Nofima’s senior scientist Bente Ruyter.

Nofima carried out feeding trials using canola oil in salmon\r\ndiets both in freshwater and seawater land-based fish tanks in Norway. Canola\r\noil was added to the feed in increasing amounts. A parallel feeding trial has\r\nalso been carried out on juvenile salmon in warmer water in Australia. This was\r\nto test canola oil at two different growth rates. This was important in order\r\nto detect any effects that might occur when fish grow rapidly during early\r\nstages of life. Nofima also carried out feeding trials where salmon were fed\r\nwith microalgae from when they were 100 grams to when they reached their\r\nslaughter size.

The salmon that were fed the new ingredients were analysed\r\nfor growth, composition, muscle quality and health. One of the purposes of the\r\nmicroalgae trial was to look at sensory parameters such as odour and taste.

The feed sources were\r\ngood for the salmon

“We know that salmon need the fatty acids EPA and DHA in\r\norder to maintain good health. This research shows that salmon can utilise\r\nthese fatty acids both from the new sources of omega-3 and from fish oil in the\r\nsame way, says Ruyter.

The main findings are:

Canola oil has a favourable fatty acid profile compared to\r\nconventional plant oils, with high levels of the omega-3 fatty acids\r\nalpha-Linolenic acid and DHA. Analysis of a number of health markers suggests\r\nthat this is a safe source of oil in salmon feed.

Canola oil in salmon feed in both freshwater and seawater\r\nprovides equivalent growth rates as fish oil, and better skin and muscle\r\ncolour.

Environmental pollutants could not be detected in salmon fed\r\nwith canola oil.

Biomass from the algae Schizochytrium sp is a good source of\r\nDHA in the diet of salmon and also contributes to better muscle colour. This\r\ningredient created no differences regarding the odour and flavour of the fillet\r\ncompared to salmon fed with fish oil.

Global challenge for\r\nthe industry

Access to greater volume of feed ingredients rich in omega-3\r\nis considered as one of the major challenges regarding growth in the\r\naquaculture industry, both in Norway and internationally.

“It now looks like there are solutions, but it will also be\r\nimportant in the future to utilise sources of omega-3 in fish as optimally as\r\npossible”, says Ruyter.

Source : The Fish Site