Salmon Oil in dog and cat food

Is it OK for dogs and cats?

Dogs

Salmon oil is a fish oil, and at the levels in complete foods it is a recognised source of EPA and DHA. A veterinary review says possible side effects in dogs, such as diarrhoea and weight gain, are likely to depend on the dose. A teaspoon of oil added to food supplies about 42 kcal.

Cats

Salmon oil can supply the DHA that FEDIAF recommends for growing and breeding cats, since young cats make little of it themselves. As with other fish oils, cats need enough vitamin E alongside it. Pansteatitis has been reported in cats fed oily fish-based diets, and Merck links it to vitamin E deficiency.

How settled this is: Depends on the amount

What salmon oil is

A fish oil obtained from salmon or salmon parts. The EU Catalogue of feed materials covers it under 'fish oil': oil from fish or fish parts with the water removed by centrifuging. That entry allows the name to include species details, so a label can name salmon.

Why it is in pet food

Salmon is an oily fish, and a study of farmed Scottish Atlantic salmon found it still supplied more EPA + DHA than most other fish species. Merck names oily fish as one of the best dietary sources of EPA and DHA. FEDIAF recommends small amounts of EPA/DHA in foods for growing and breeding dogs and cats. Essential fatty acid supplements are also used for skin problems. For essential fatty acid products in general, not salmon oil alone, Merck reports that about 20% of dogs and 50% of cats with allergic itching show some improvement.

What it does in the food

Salmon oil provides EPA and DHA, and how much depends on the fish. In a study of more than 3,000 farmed Scottish Atlantic salmon, EPA + DHA in the flesh fell from an average of 2.74 g to 1.36 g per 100 g between 2006 and 2015. Over that time, salmon feeds replaced part of their fishmeal and fish oil with plant ingredients. That study measured salmon flesh, not salmon oil. FEDIAF recommends EPA + DHA of 0.05 g per 100 g dry matter in dog foods and 0.01 g in cat foods for growth and reproduction, and sets no level for adults. Like other oils, salmon oil has about 9 kcal per gram.

Safety and limits

Salmon oil shares the profile of fish oil. A 2013 veterinary review listed possible adverse effects of omega-3 supplements in dogs and cats. These include diarrhoea and vomiting, changes in platelet function, slower wound healing, lipid peroxidation, weight gain, changes in immune function and drug interactions. The authors say effects, if seen, are likely to depend on the dose. EPA and DHA are highly unsaturated, so the oil oxidises easily. Vitamin E helps prevent this, and vitamin E needs rise with polyunsaturated fat intake. FEDIAF recommends 5–10 IU of extra vitamin E per gram of fish oil per kg of cat food. The review rates the overall risk from contaminants such as mercury as low. It notes that signs of mercury toxicity are seen more often in cats, because cats are fed fish-based diets more often.

What depends on the amount and the recipe

The total dose, especially when salmon oil is added on top of a complete food; how fresh the oil is and its vitamin E protection; the EPA and DHA content of the source fish, which varies with the salmon's diet; species and life stage; and the pet's medical conditions and medicines.

Not the same as

• Fish oil — Can come from any fish species or a mix; salmon oil names one species.
• Salmon meal — A dried protein ingredient made from salmon, not an oil.
• Krill oil — Oil from marine plankton (krill), not fish; the EU catalogue lists it separately.
• Cod liver oil — A fish liver oil; reviewers flag possible vitamin A and D excess with high-dose cod liver oil supplements.

Sources

1. Commission Regulation (EU) No 68/2013 on the Catalogue of feed materials, consolidated text of 24.07.2022 (entries 10.4.2 Fish meal, 10.4.6 Fish oil, 10.5.1 Krill oil) — Publications Office of the European Union, 2013 (consolidated 2022). Fish oil is oil from fish or fish parts, centrifuged to remove water, and its name may include species-specific details; fish meal is a separate dried product; krill oil is a separate entry.
2. Sprague M, Dick JR, Tocher DR. Impact of sustainable feeds on omega-3 long-chain fatty acid levels in farmed Atlantic salmon, 2006-2015. Sci Rep 6:21892 — Scientific Reports (via PubMed Central), 2016. Salmon is an oily fish rich in EPA and DHA; in over 3,000 farmed Scottish salmon, EPA + DHA in flesh fell from 2.74 g to 1.36 g per 100 g between 2006 and 2015 as plant ingredients replaced fishmeal and fish oil in salmon feed; farmed salmon still supplies more EPA + DHA than most other fish.
3. Lenox CE, Bauer JE. Potential adverse effects of omega-3 fatty acids in dogs and cats. J Vet Intern Med 27(2):217-226 — Journal of Veterinary Internal Medicine, 2013. Possible adverse effects of fish oil omega-3s; effects likely dose-dependent; oxidation and the protective role of vitamin E; about 9 kcal per gram and 42 kcal per teaspoon; low overall contaminant risk, with mercury signs more common in cats; pansteatitis in cats on oily fish diets; vitamin A/D concern with cod liver oil.
4. FEDIAF Nutritional Guidelines for Complete and Complementary Pet Food for Cats and Dogs — FEDIAF (European Pet Food Industry Federation), 2025. EPA + DHA recommendations for growth and reproduction in dogs and cats and no level for adults; young cats have low DHA synthesis; vitamin E needs rise with PUFA intake, with 5–10 IU extra per gram of fish oil per kg of cat food.
5. Nutritional Requirements of Small Animals (Merck Veterinary Manual, professional version) — Merck & Co. (Merck Veterinary Manual), 2024. EPA and DHA are required during growth and reproduction; oily fish, krill oil and algae oil are the best dietary sources of EPA and DHA; vitamin E deficiency causing pansteatitis in cats fed large amounts of canned tuna.
6. Essential Fatty Acids for Integumentary Disease in Animals (Merck Veterinary Manual) — Merck & Co. (Merck Veterinary Manual), 2022 (updated 2025). About 20% of dogs and 50% of cats with allergic itching improve on essential fatty acids; large doses may cause weight gain or diarrhoea.

Checked against these sources on 2026-10-15. Definitions are in our own words. This is a reading aid, not veterinary advice: a vet who knows your animal comes first.