Results from a series of salmon feeding trials run by Skretting Aquaculture Research Centre (ARC) revealed a new low limit for fishmeal in salmon grower feeds.

The trials, conducted on fish from one to five kg, showed excellent growth and a low feed conversion rate (FCR) on salmon given feed with 15 percent fishmeal and no land animal protein.

Dr Alex Obach, Managing Director of Skretting ARC, gives some details. ''We used three feeds and the best results came from an experimental feed using only 15 percent fishmeal together with active ingredients we are currently investigating. The two other feeds were a more conventional feed with 25 percent fishmeal and a similar experimental feed using 15 percent fishmeal but without the active ingredients. The results totally change our previous belief that the lower limit for fishmeal was 25 percent unless land animal proteins were used. At present, that is not possible for salmon production in Europe.''

The trials were conducted at Skretting ARC Fish Trials Station and Helgeland Havbruksstasjon, both located in Norway. The trial at Helgeland used three groups of 180 fish starting at around 2.6 kg. Over the 73 days they grew to around 4.7 kg. All three groups of fish showed excellent performance.

The high fishmeal (25 percent) control group achieved a relative growth index (RGI) of 169 percent (specific growth rate/SGR=0.85 percent/day), however, the group fed the feed with 15 percent fishmeal plus active ingredients achieved an RGI of 172 percent (SGR=0.87 percent/day). The group fed the basic 15 percent fishmeal feed recorded an RGI of 152 percent (SGR=0.76 percent/day). The reduction in fishmeal showed no negative effects on fish quality and monitoring throughout the trials also showed the fish maintained a good health status. FCR was below one for all groups.

Dr Obach said, ''It is the first time we have achieved such good results in growth and FCR with low fishmeal feeds without using land animal proteins. Although Skretting will not implement the results yet in commercial feeds, they demonstrate a significant potential for extending our use of sustainable fishmeal over a much greater production of farmed Atlantic salmon. Around two-thirds more salmon could be grown from the same volume of fishmeal.''

Skretting produces and supplies feed for farmed fish, with its total annual feed production exceeding 1.3 million tonnes. Skretting has operating companies on five continents to produce and deliver feeds from hatching to harvest for more than 50 species of farmed fish. Skretting is a part of Nutreco; an international company in the animal nutrition and fish feed markets.