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The effects of feed on shrimp pigmentation Logo Feedia

The pink-orange color of cooked shrimp comes from their ingested carotenoid pigments. Since they are unable to synthesize their own pigments, shrimp must find them in their feed. Pigments are useful to their metabolism and have a strong impact on the ability to market them as finished products. Pigments are therefore a major challenge for prawn producers. How can the pigmentation of shrimps be improved in the context of rearing?

Feed as the sole source of pigments for shrimp

In nature and in extensive or semi-intensive farms, shrimp absorb microorganisms, such as microalgae, that are rich in carotenoids. Carotenoids are pigments that give prawns their characteristic pink-orange color. Even though the Carotenoid family is quite large, only a few of its compounds have an impact of pigmentation. Among them, astaxanthin is the most effective pigment in impacting  the color of shrimp. The majority of shellfish can also produce astaxanthin from other pigments such as β-Carotene.

Pigmentation des crevettes

Carotenoid pigments also fulfill major physiological functions. For example, some carotenoids act as the precursors of Vitamin A. These antioxidants also have the ability to protect the organism against free radicals. Carotenoids in shrimp can thus help reduce the negative impacts of an inflammatory response.

As production systems intensify, there comes a point when the natural productivity of ponds is no longer enough to produce the necessary pigments for shrimp. When intensification is effective, feed therefore becomes the main source of pigments for farmed shrimp.
The pigments contained in feed either come from raw materials, from specific synthetized ingredients or components of natural origin.

How to measure the level of pigmentation in shrimp?

The pigmentation of shrimp has a major impact on a consumer’s decision to buy them as a marked pigmentation shows a guarantee of quality. Consequently, the level of pigmentation in a shrimp population  needs to be monitored closely.

Two main methods are used to determine the intensity of pigmentation in shrimp:

  • comparing the color of cooked shrimp with the hues of a reference color chart. This is a simple and effective method, but the results can vary depending on who undertakes this action.
  • measuring the tissue color using special tools like Chroma. This measure gives a result that can be split into three components, often expressed L * a * b: brightness (L), clarity (red line a) and saturation (yellow axis, b).

How can the pigments be kept?

Pigments, whatever their origin, are delicate molecules. They are especially sensitive to oxidation. It is of paramount importance to ensure that these ingredients, along with feed, are kept in good storage conditions. Exposition to moisture, direct sunlight and high temperatures ought to be carefully avoided. Pigments are also fat-soluble molecules, so the fat content of the feed and its digestibility have a strong impact on their fastness.
An interesting nutritional option to compensate for the losses of pigments is the use of emulsifiers.To this end, the use of antioxidants is also recommended. Finally, pigments are sometimes added to vitamin and mineral premixes. In these conditions, the presence of prooxidant minerals can immediately and substantially alter the pigments.

All these factors must be taken into account in the formulation process. The goal is to produce healthy animals with the pigmentation sought by consumers. The Techna Group supports farmers and feed manufacturers in their search for effective solutions to enhance and optimize shrimp pigmentation, either at the formulation stage, in the choosing of raw materials, or through the use of additive premixes. For more details, please do not hesitate to contact our experts at Techna.

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