Holistic Health Hub

Sardines, Mackerel, and Salmon

Incorporating oily fish into a canine diet provides critical long-chain omega-3 fatty acids (EPA and DHA) and essential micronutrients such as vitamin D and selenium. While all three—sardines, mackerel, and salmon—offer nutritional value, sardines and mackerel are generally more appropriate for routine inclusion in canine diets, with salmon recommended as an occasional addition due to several important considerations.

Nutritional Comparison and Benefits

1. Micronutrient Density
Sardines and mackerel are particularly rich in vitamin D and selenium, both of which are essential in canine nutrition and may be marginal or absent in home-prepared diets without seafood or organ meats. Vitamin D is critical for calcium homeostasis, while selenium supports cellular antioxidant defenses. These nutrients are often deficient or completely lacking in home made diets.

2. Omega-3 Fatty Acids (EPA and DHA)
All three species contain high levels of EPA and DHA, which contribute to reduced systemic inflammation, improved skin and coat health, immune modulation, and support for cardiac and cognitive function. These fatty acids are more bioavailable from fish sources compared to plant-based omega-3s (e.g., alpha-linolenic acid from flax) and are critical in both developing and adult dogs.

3. Contaminant Load and Bioaccumulation
Smaller forage fish such as sardines and mackerel accumulate fewer environmental toxins (e.g., methylmercury, dioxins, PCBs) than larger, longer-lived species like salmon. Including low-trophic-level fish in the canine diet minimizes exposure to persistent environmental pollutants over time.

4. Cost and Accessibility
Sardines—particularly canned in water without added salt—are widely available, economical, and require no special preparation. Mackerel is similarly cost-effective and easy to incorporate. These characteristics make them practical sources of omega-3s and trace minerals in daily feeding.

Safety Concerns with Salmon

Parasitic Risk in Wild-Caught Salmon
In specific regions of the Pacific Northwest (e.g., Alaska, Washington, British Columbia), wild salmon may carry the parasitic fluke Nanophyetus salmincola, which transmits Neorickettsia helminthoeca, the causative agent of Salmon Poisoning Disease (SPD) in dogs. SPD can be fatal without treatment. Risk is eliminated by cooking or freezing at −20°C for 7 days, or −35°C for 24 hours (FDA, 2020). Canned or cooked salmon is safe.

Concerns with Farmed Salmon
Farmed salmon—particularly Atlantic salmon—presents several nutritional and environmental concerns:

  • Elevated Omega-6 to Omega-3 Ratio: Due to grain- and soy-based feeds, farmed salmon often has a higher omega-6 content, reducing its anti-inflammatory benefit compared to wild salmon.

  • Contaminant Levels: Farmed salmon may contain higher concentrations of fat-soluble pollutants, such as PCBsand dioxins, due to feed composition and rearing conditions. A study from Norway (2005) found farmed salmon had significantly higher contaminant levels than wild salmon.

  • Use of Antibiotics and Pesticides: Farmed salmon are often treated with medications to control disease and parasites, which can raise concerns about residue exposure and environmental impact.

  • Artificial Pigmentation: Astaxanthin analogs are added to feed to achieve the pink coloration of farmed salmon, though this is not inherently harmful, it is a marker of feed manipulation.

Where salmon is used in the diet, wild-caught sources are generally preferable from both a nutritional and toxicological standpoint, provided parasite control measures are followed.

Feeding Recommendations

  • Sardines and mackerel (preferably wild-caught): Feed 1–3 times per week depending on the size of the dog and overall diet composition. These can be served raw (if safe), cooked, or canned in water with no added salt.

  • Salmon: Offer occasionally. Use wild-caught, previously frozen, cooked, or canned salmon from safe sources. Avoid feeding raw wild salmon unless it has been deep-frozen appropriately. Avoid routine use of farmed salmon due to lower nutrient quality and higher contaminant load.

Avoid smoked, salted, or heavily processed fish products.

Conclusion

Sardines and mackerel are highly recommended as regular additions to canine diets due to their superior micronutrient profile, low contaminant risk, affordability, and digestibility. Salmon provides valuable omega-3s but should be fed with caution due to parasitic and environmental concerns. Farmed salmon, in particular, may not be nutritionally equivalent to wild salmon and is best used sparingly or avoided in dogs with inflammatory conditions or compromised detoxification systems.

References

  • Lenox, C. E., & Bauer, J. E. (2013). Potential adverse effects of omega-3 fatty acids in dogs and cats. Journal of Veterinary Internal Medicine, 27(2), 217–226. https://doi.org/10.1111/jvim.12033

  • National Research Council. (2006). Nutrient Requirements of Dogs and Cats. Washington, DC: The National Academies Press. https://nap.nationalacademies.org/catalog/10668/nutrient-requirements-of-dogs-and-cats

  • Food and Drug Administration (2020). Raw Pet Foods Can Be Dangerous for You and Your Pet. https://www.fda.gov/animal-veterinary/animal-health-literacy/raw-pet-foods-can-be-dangerous-you-and-your-pet

  • Hites, R. A. et al. (2004). Global assessment of organic contaminants in farmed salmon. Science, 303(5655), 226–229. https://www.science.org/doi/10.1126/science.1091447

Jackie Gowland