Fish showed little adverse effect from a diet with hardly any fishmeal or oil. Photo: Library picture

Fish ‘can thrive’ on very low fishmeal diet

A large-scale European project that examined the shift to very low levels of fishmeal and fish oil in feed has found the reduction has little detrimental effect on farmed fish.

The five-year, €8 million Advanced Research Initiatives for Nutrition and Aquaculture (ARRAINA) study looked at rainbow trout, Atlantic salmon, carp, sea bream and sea bass. Throughout the life cycle of the fish, growth, health, reproductive capacity, and nutritional qualities have all been scrutinised.

Work included testing various plant-based feeds at an experimental farm in southern France.

“Ten years ago, food was made of about 30 or 40 per cent fish meal,” said farm manager Frédéric Terrier. “Today that’s been reduced by between 15 and 20 per cent and we’re working to further reduce it.”

Mixed results

“We’ve clearly seen that all these species are capable of thriving without much of a harmful effect on any level,” ARRAINA project coordinator Sadasivam Kaushik told Euronews. “Except in some cases when you go for really, really low levels, zero zero, then you can have some effects.”

The French National Institute for Agricultural Research, INRA, has had mixed results with a 100 per cent plant-based diet. It found that fish grow slower and don’t reproduce as easily. The nutritional properties are also lower. But scientists say there are solutions.

“With plant-based foods, there is less omega 3 fatty acid in the flesh. Strategies to counteract this effect are already known,” said Geneviève Corraze, fish nutrition expert at INRA. “Before the slaughter one can, for a few weeks or a month, give a food based on marine ingredients. That will ‘reswitch’ the fatty acid composition. The second possibility is genetic selection, in other words, there are animals that have more ability to synthesize and retain these omega 3 fatty acids.”

Farmers reluctant

One of the project partners is Biomar, one of the world’s leading producers of fish food and a big advocate of using plant-based proteins.

Wheat, rapeseed, corn, vitamins and minerals are combined with fishmeal and fish oils to make food granules.

“We know how to make food with between 2 and 5 per cent of fishmeal and 2 to 5 per cent of oil and have a trout that is completely edible, healthy and tasty,” said Michel Autin, marine product manager, Biomar.

“There is a certain reluctance… fish farmers demand certain levels of oil and fishmeal because they feel more assured. That is quite natural and legitimate but the trend is to have less and less.”

The ARRAINA project involved 21 partners including 10 scientific institutions and nine European companies.

Published: 12/07/2017 at 6:49 am

Latest news

Farm Manager and Assistant Farm Manager

Marine Harvest Scotland