What’s really on your plate? « Euro Weekly News

If you buy salmon because you think you know what goes into it, think again, there is something about the fish on sale in some European supermarkets that may surprise you. Several Norwegian salmon producers are now using ingredients made from chicken by-products in their feed, replacing part of the fishmeal and other proteins traditionally used to raise farmed salmon.

This does not mean throwing raw chicken leftovers into the water. The poultry material is processed into meal and oil before being mixed into formulated fish feed. It can include bones, liver and other parts of chickens that are not normally sold as meat cuts. Producers are turning to it because it offers a cheaper alternative at a time when traditional marine ingredients are becoming more expensive and harder to source.

Why salmon producers are changing the menu

Fishmeal and fish oil have long been important ingredients in farmed salmon diets, providing protein and essential nutrients. However, they rely on catches of wild fish, and supplies have come under pressure. Disruption to Peru’s anchovy fishery, an important source of fishmeal, has added to the problem, while the availability of other marine ingredients has also been affected. Poultry meal is reported to cost less than half as much per tonne as fishmeal, making it an attractive option for companies trying to control production costs.

Lerøy Seafood Group has introduced poultry-derived ingredients at all its offshore salmon farms in Norway. Grieg Seafood began using chicken meal and oil in July, while SalMar started testing poultry-based feed in March. Mowi has also been reported to be preparing similar changes in Norway, although its position varies between markets and operations. The companies argue that using material left over from chicken processing makes better use of existing resources and reduces reliance on wild fish caught for feed. The industry is under pressure to find alternative protein sources as demand for farmed fish continues to grow.

What exactly is being fed to the fish?

Poultry by-product meal is made by processing material left over after chicken meat production. Depending on the source, this can include bones, organs and other parts not sold for human consumption. It is treated before being used in animal feed; it is not simply discarded kitchen waste.

Norwegian research institute Nofima is investigating how chicken residues can be used in salmon feed, including how processing affects protein digestibility and biological quality. Its research project runs until September 2027 and will also examine the effects of longer-term feeding on fish health, growth and the quality of salmon at slaughter.

The nutritional value of poultry meal can vary. Nofima says digestibility has sometimes been low, with heat treatment, freshness and the type of material used all affecting the result. The research is intended to establish how the ingredients should be selected and processed to produce a consistent feed component.

Could it increase the risk of antibiotic-resistant bacteria?

Using animal by-products in feed also raises questions about bacteria and antibiotic resistance. Chicken production, like other livestock industries, can be a source of bacteria carrying resistance to antibiotics. If contaminated material entered the feed chain without effective treatment and controls, there could be a route for bacteria or resistance genes to spread.  That is a potential food-safety concern, not proof that salmon fed poultry meal will contain antibiotic-resistant bacteria. Processing requirements are designed to reduce microbiological risks, and feed ingredients are subject to safety controls.

Norway’s Institute of Marine Research detected Salmonella in one sample of feather meal during its 2025 fish-feed monitoring programme. The report nevertheless described the general microbiological quality of the samples as satisfactory. The finding does not show that salmon fillets were contaminated or that poultry meal is spreading antibiotic resistance, but it demonstrates why sourcing, processing and testing matter. Separate research into salmon and chicken processing environments has identified antibiotic-resistance genes in some processing waste streams. However, it did not demonstrate that feeding poultry by-products to salmon transfers resistant bacteria into the fish or its flesh. 

Does chicken feed affect the quality of salmon?

There is also the question of whether changing the fish’s diet affects the quality of the meat people eventually eat. A commercial-scale study published in 2025 examined 435,000 Atlantic salmon over an 11-month feeding period. Poultry by-product meal replaced 5 or 10 per cent of the crude protein from conventional sources in the test diets. Researchers found no significant differences in growth, mortality, feed conversion, gut condition or fillet quality.

There were also no differences in the colour, firmness, gaping or fatty acid composition of the salmon. The findings do not support claims that moderate amounts of poultry meal automatically make salmon less nutritious or damage the texture of its flesh. However, they do not settle every question about different feed formulas or higher levels of inclusion. Nofima’s wider research is still examining long-term effects, including smell, appearance, taste and texture. 

Shoppers may not know what their salmon has eaten

For consumers, one of the biggest concerns is transparency. Feed ingredients do not generally have to be listed on supermarket salmon packaging, meaning shoppers may not be able to tell whether the fish they buy was raised on a diet containing poultry by-products. A Nofima survey of more than 1,000 consumers in England and France found that many knew relatively little about the ingredients in farmed salmon feed. Chicken-based ingredients were viewed particularly negatively, with respondents often associating them with something unnatural or lower quality. 

The debate is likely to continue as producers look for cheaper alternatives to fishmeal. The available research does not show that salmon fed poultry meal is automatically unsafe or inferior, but questions remain about how ingredients are sourced, processed and tested, how much is used and whether shoppers should be told. For anyone buying salmon, the change raises eyebrows: should consumers have the right to know what the fish on their plate has been fed? I think so.