What Makes Salmon Pink?

1) Why are Salmon pink?  

The characteristic pink-red color of salmon flesh results from the retention of carotenoids in the fish flesh.   These carotenoids are derived from the diet of the salmon in the wild (small crustaceans) and from naturally derived or synthesized feed ingredients for farmed salmon.

2) What are carotenoids?

The term "carotenoid" is actually a generic term describing a large group of naturally occurring biochemicals (over 600 different types have been identified to date in plants and animals).   They are responsible for the wonderful yellow-to-red colors in many fruits (tomatoes, paprika, citrus fruits), flowers (marigolds), insects (ladybugs), birds (chickens, flamingos), fish (salmon, goldfish), crustaceans (shrimp, lobster) and mammals.   Even more importantly they have biological roles and are an essential nutrient, necessary for the general health of salmon.

3) What carotenoids are used in aquaculture?

Astaxanthin and Canthaxanthin are used in aquaculture feeds.   Both are also found in wild salmon with astaxanthin being predominant (over 90%).   Astaxanthin is the major carotenoid responsible for the pink-red color of wild fish and shrimp.

4) What is the source of astaxanthin in the wild?

Salmon cannot make their own carotenoids and must obtain it in the diet.   Salmon in the wild obtain astaxanthin from the krill and other small crustaceans eaten as part of their diet.   These crustaceans, in turn, obtained it from eating various microorganisms, fungi, microalgae and certain higher plants which are able to produce astaxanthin.

5) Is there a difference between natural and synthetic astaxanthin?

No, their chemical structures are identical.   Nevertheless, in addition to synthetically derived astaxanthin, it is also available as a product derived from a "natural" source of yeast ( Phaffia sp.) and microalgae ( Haematococcus sp.) for use in producing "organic" fish and seafood.

6) Why are carotenoids added to the feed of salmon?

There are two reasons that animal nutritionists and aquaculturists cite for adding carotenoids to salmon feeds.   Carotenoids are a natural part of the salmon diet in the wild, so these substances are added to mimic that natural diet as closely as possible.   The second reason is for the general health of the fish - Astaxanthin has been demonstrated to be an essential nutrient for salmon.   Fry from female salmon fed carotenoid-free diets die unless they are fed diets containing astaxanthin.  

7) Why does farm-raised salmon have "color-added" on the label?

Seafood companies do not add color directly to salmon fillets, steaks and other market forms of the fish. However, the Food and Drug Administration, which approved astaxanthin and canthaxanthin as safe feed ingredients for farmed raised salmonids (salmon and trout), requires that feeds containing carotenoids and the fish subsequently fed these feeds bear a "color-added" label.

8) Is it safe to consume salmon raised with carotenoid-containing feed?

Canthaxanthin was approved years ago as a feed additive for poultry. More recently, the Food and Drug Administration reviewed the safety data concerning the two carotenoids for their use in salmonid feeds and found them to be safe for that intended use. FDA set specific maximum allowable levels in the feed and calculated how much would enter the fish flesh. The FDA limits in salmon feed keep the amount of carotenoids in farmed salmon from exceeding the levels of carotenoids found in wild-caught salmon. An expert familiar with carotenoids has stated that carotenoid pigments are broken down by cooking/ processing and that, in toxicity testing, canthaxanthin was shown to be safer than salt