The demand for salmon has grown in recent years and we have seen (and proven) that it is a great companion to one of the most popular foods, avocado. In addition to its incredible nutritional benefits, this fish stands out for its striking pinkish-orange color.
However, its natural color is gray. Salmon can naturally “look” orange-pink due to their diet, mainly based on crustaceans. On the other hand, farmed salmon are not fed the same. Therefore, how do they change the color of the fish in fish farms?
“In nature, salmon eat small crustaceans, krill and other prey that give them this coloration that accumulates in their muscles and skin,” explains Lourdes Reig, a 35-year-old professor at the Polytechnic University of Catalonia (UPC). of experience in the world of aquaculture.
Javier Ojeda, manager of the Aquaculture Business Association of Spain (APROMAR), points out that “salmon, like oranges, has pigments that are formed from its diet.” However, as Reig points out, “under farming conditions, the food that the salmon eats is basically made up of fish meal and vegetable meal, therefore, it does not achieve this coloration.” The solution, explains Ojeda, is to provide astaxanthin on farms. Reig points to the introduction of the substance into feed “in the last stages of cultivation.”
A precursor substance to vitamin A
Astaxanthin is the pigment responsible for color. Reig explains that “it is found naturally in many organisms and in some species of phytoplankton and bacteria.” In addition to being responsible for giving color, “the pigment is a precursor substance to vitamin A, that is, it contributes to the growth and health of the fish,” says Reig.
In the case of wild salmon, the way to obtain astaxanthin is clear: everything goes through the food chain. But how do farmed fish incorporate the substance? Reig explains that in addition to natural sources (algae, plankton, bacteria and crustaceans), it can also be synthesized in a way identical to natural sources. In the case of organic feed, “you can only use the natural form,” he points out.
If the diet of farmed salmon is not strictly the same as that of wild salmon, why does its color change? They both agree that everything is due to commercial reasons. “It is the consumer who asks that the salmon have this color. The same goes for eggs and chicken. We all know that there are eggs with different shades of yolk (between yellow and orange), and we know that there are yellow and white chicken. In these two cases, the coloring is achieved by adding the same pigment to the feed.”
Ojeda believes that this is done because the consumer recognizes salmon because of its characteristic color. “It is a practice that does not happen only in aquaculture.” The APROMAR manager gives the example of carrots that “by nature are not orange, but no one can imagine buying carrots that are not that color.”
Despite recognizing the weight that coloring has in commercial matters, both consider the practice to be beneficial. Ojeda points out that the substance is very important for the salmon diet. The teacher agrees and remembers that astaxanthin is a precursor of vitamin A, which is very important and provides benefits for growth and health. “Farmed salmon could live without this pigment, since it has a supply of vitamin A in other elements of the feed.”
Furthermore, he explains, this process increases the price of feed and, consequently, the cost of production, but since it is added due to a market requirement, “at least we know that it is not harmful, quite the opposite.” However, he advises the consumer to be careful about what is asked of the food industry.
“Farmed salmon would have the same taste and nutritional qualities without the pigment, but we want it with the characteristic coloration with which we know it. The same thing happens with rainbow trout. A few decades ago, white and salmon trout (with the same pigment) were produced. Now, in the market almost all the trout is salmon.”
But is it legal?
Although the pigment does not change the taste or nutritional qualities, there are countries like New Zealand and Australia where the practice is prohibited. To defend the legality of the addition of astaxanthin, Ojeda hides behind the regulations of the king of salmon, Norway. “Norwegian regulations allow this practice and I can assure you that it is one of the most demanding there is.” He points out that in their fish farms they try to ensure that the diet is as close as possible to that of wild animals, as this ensures that they develop and have the best quality.
Reig points out that “in the last decade the dose of pigment has been reduced, limiting it to the minimum necessary to achieve the desired coloration and the use of pigment has also been limited in the first months of the fish’s life. It is true that there are countries that greatly limit the introduction of additions, allowing only those that are essential for the preservation of food. I might agree with this philosophy. In this case, it is an additive with a mainly aesthetic purpose but, at least, we know that it does not harm us and can be beneficial for the fish.”
