Salmon is one of the most popular and nutritious fish consumed around the world. In the wild, salmon get their distinctive pink-orange hue from eating krill and other small crustaceans that contain natural astaxanthin, a carotenoid pigment. However, most salmon today comes from large-scale aquaculture operations, which has led to questions around whether colour is artificially added to farmed salmon.
The colour of salmon flesh is mainly determined by their diet. Wild salmon eat diverse marine organisms that contain natural astaxanthin and other carotenoids. Meanwhile, farmed salmon are fed formulated fish feed that may lack sufficient levels of astaxanthin for desired pigmentation. This has prompted some salmon farms to add synthetic astaxanthin or other colour additives to feeds or directly to the fish. The use of colour additives remains controversial and disputed by different stakeholders.
In this article, we’ll take an in-depth look at the use of colour additives in farmed salmon, including key considerations around nutrition, safety, regulations, and transparency for consumers.
Natural Salmon Coloration
In the wild, salmon obtain their characteristic pink-red hue from consuming krill, shrimp, and other small marine organisms that contain natural carotenoid pigments like astaxanthin. These pigments are absorbed into the muscle tissue of the fish.
Astaxanthin and related carotenoids act as antioxidants and play important roles in salmon health and survival. They help protect the fish from oxidation, inflammation, and damage from UV light exposure. The vibrant reddish coloration of wild salmon comes from years of foraging on diverse marine foods containing high levels of carotenoids.
Here is a table summarizing the main pigments responsible for wild salmon coloration:
| Pigment | Primary Source in Diet |
|---|---|
| Astaxanthin | Krill, shrimp, crayfish |
| Canthaxanthin | Copepods, shrimp |
| Zeaxanthin | Marine algae |
These pigments are accumulated over time as salmon forage in the productive waters of the Pacific and Atlantic oceans. The resulting vibrant pink-red coloration occurs naturally as salmon store high levels of carotenoids in their muscle tissue.
Farmed Salmon Color
In aquaculture settings, salmon are reared in enclosed pens and fed formulated feed pellets that contain proteins, oils, vitamins, and minerals to support growth. However, the standard feeds often lack sufficient quantities of astaxanthin and other carotenoids found in wild salmon diets. Without adequate pigments in their feed, farmed salmon would have pale flesh rather than the desired pink-red color consumers expect.
To achieve pigmentation levels comparable to wild salmon, most farmed salmon feeds contain added carotenoids, usually in the form of synthetic astaxanthin. Astaxanthin is approved for use as a feed additive and typically added at levels of 50-100 mg/kg of fish feed. With sustained delivery of supplementary astaxanthin, farmed salmon take on the familiar orangish-pink tone within four to six months.
Besides astaxanthin, some farms may use synthetic canthaxanthin as a colorant in feeds or applied directly on the fish skin. However, canthaxanthin has lower antioxidant value and may build up to higher levels in fish tissues compared to natural pigments. Both astaxanthin and canthaxanthin used in aquaculture are synthetically produced.
Regulations on Color Additives
In most major salmon farming countries, including Norway, Chile, Canada and the UK, synthetic astaxanthin is legal to add when used according to approved limits. Astaxanthin supplementation must follow regulatory guidelines to ensure safe and appropriate usage.
In the United States, the FDA has approved synthetic astaxanthin as a compound generally recognized as safe (GRAS) for specific use levels in salmonid fish feeds:
| Species | Maximum astaxanthin |
|---|---|
| Salmon | 100 mg/kg feed |
| Trout | 80 mg/kg feed |
Compliance with national laws and safety standards helps ensure responsible use of coloring additives. However, oversight and enforcement of regulations varies between countries. Some consumers may still have concerns about overuse or misleading labeling of pigment additions in farmed salmon feeds.
Consumer Perception and Transparency
Many consumers assume the bright pink-red color of raw salmon implies superior quality and nutritional value. However, the color itself does not necessarily indicate healthier or safer salmon. Farmed salmon with paler flesh can still have excellent meat quality and nutritional content. Nonetheless, consumers tend to judge quality by color alone, associating deeper hues with wild origin.
This triggers debate around transparency regarding pigment additions in farmed salmon. Some advocacy groups argue that use of synthetic astaxanthin or canthaxanthin should be clearly labelled to avoid misleading consumers. They propose that artifically colored farmed salmon should be labeled as such, rather than simply as “salmon”.
However, aquaculture producers contend that synthetic astaxanthin itself is a safe, legal substance identical to natural astaxanthin. They claim that as long as colorants are added according to regulations, specific labeling is unnecessary.
This presents an ongoing dispute affecting consumer trust and transparency. Clear product labeling provides consumers the right to make informed choices about farmed salmon based on their personal values regarding color additives.
Nutritional Value
Astaxanthin and related carotenoids contribute important nutritional value in salmon. The pigments serve as potent antioxidants, helping protect cell membranes and tissue from oxidative damage. Carotenoids also support immune function and eye health in salmon.
However, the nutritional value depends on the source and form of the pigments:
| Source | Nutritional value |
|---|---|
| Natural (krill, etc.) | High |
| Synthetic astaxanthin | Moderate |
| Synthetic canthaxanthin | Low |
Natural carotenoids from marine organisms provide better nutritional quality due to their diversity and integration with fats, proteins and other nutrients. Synthetic astaxanthin still retains significant antioxidant effects, but less so than whole food sources. Meanwhile, canthaxanthin has lower antioxidant activity in salmon flesh.
From a nutritional standpoint, feed containing a variety of natural pigment sources provides an ideal balance of carotenoids and other beneficial nutrients. However, synthetic astaxanthin used within regulated limits can be a suitable substitute to achieve desired salmon coloration and nutritional goals.
Safety and Health Risks
Both natural and synthetic forms of astaxanthin and canthaxanthin are considered safe for use in animal feeds. After extensive safety reviews, regulatory agencies including the FDA, EFSA and FSA have approved prescribed levels for salmonid feeds that are not expected to pose risks to the fish or consumers.
Synthetic astaxanthin solubilized with solvents may have higher bioavailability compared to natural esterified forms from crustacean shells. Therefore, some experts recommend limits on accumulation levels in salmon flesh to prevent potential excess intake in humans:
| Pigment | Maximum level in flesh |
|---|---|
| Astaxanthin | 10 mg/kg |
| Canthaxanthin | 2 mg/kg |
However, when used according to feed additive guidelines, both astaxanthin and canthaxanthin show very low toxicity even at high intakes. Synthetic colors added to farmed salmon are not intrinsically harmful if used responsibly. Nonetheless, some consumers may prefer to limit exposure to artificially high concentrations from produced sources.
Environmental Considerations
Aquaculture operators highlight the sustainability benefits of astaxanthin supplementation in salmon feeds. Adding pigments enables efficient feed conversion, faster growth and use of less marine ingredients like fishmeal. The improved feed efficiency and land-based production of synthetic carotenoids can reduce environmental impacts related to overfishing wild stocks.
However, critics argue that producing synthetic astaxanthin depends on petrochemicals, solvents, and non-renewable resources. Overreliance on mass-produced pigments perpetuates an artificial system disconnected from natural marine nutrient cycles. They advocate exploring feeds with more diverse, ecologically-derived carotenoid sources to improve environmental sustainability.
As with many aquaculture practices, the debate involves complex trade-offs between efficiency and synthetic inputs versus environmental impacts and sustainability. There are also opportunities to derive astaxanthin from renewable biomass like microalgae. Ultimately, conscientious sourcing and use of pigment additives can balance health, transparency and ecological factors.
Conclusion
In summary, colour addition in farmed salmon remains a contentious issue with valid perspectives on both sides. Salmon farmers and industry groups maintain that synthetic astaxanthin is safe, efficient and necessary to meet market colour standards. However, some advocacy organizations and consumers argue for greater transparency and reduced reliance on artificial pigments.
Compromises may be found through innovative feed formulas that blend natural marine carotenoids with lower levels of synthetic astaxanthin. Clear country-of-origin labeling and production methods on market salmon can also enable consumers to make informed choices aligning with their values.
Achieving the appealing colour is just one aspect of salmon farming. More important considerations are producing nutritious salmon in ways that support animal health, human wellbeing and ecological sustainability. Thoughtful use of pigment additives can be incorporated into responsible practices to balance consumer expectations with principles of aquaculture stewardship. With forward-thinking standards, salmon farmers can offer quality products that both look good and do good.