There are many traits that determine consumer acceptability, market price and perceived product quality of fish and shrimp. One of the most important traits to consider is color.
Consumers prefer shrimp that looks bright orange-red when cooked. Shrimp with a high color grade is given a higher market value in premium segments. Because of this, shrimp producers have been looking for cost-effective solutions to improve shrimp color.
In this article, I will explain how you can improve shrimp color and prove that investing in your trace mineral program can also improve efficiency and reduce the cost of shrimp production.
Improving Shrimp Color with Astaxanthin
One solution frequently used by shrimp producers to improve color is to supplement shrimp feed with astaxanthin and other carotenoids. The colors of aquatic animals grown in their natural environment come from compounds in microorganisms like microalgae. But the color of farmed shrimp is dependent on the amount of pigment, primarily from astaxanthin, supplied through the diet. Supplementing 25–100 mg/kg of astaxanthin for about a month has shown to be the most effective approach.
In addition to its role in improving shrimp color, astaxanthin plays an important role as an antioxidant. So the efficiency with which it is used for pigmentation depends on how well the shrimp’s antioxidant needs are being met with other nutrients in the diet.
Trace Minerals Play a Key Role in Antioxidant Defense
Fish and shrimp require antioxidants to defend against damage from reactive oxygen species (ROS). Antioxidants like superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase scavenge free radicals and contribute to the body’s enzymatic antioxidative defenses. These enzymes require trace minerals like zinc, manganese, copper, iron and selenium for optimal activity (Fig. 1).
Inadequate dietary intake of these trace minerals may compromise the effectiveness of antioxidant defense, requiring the shrimp to use astaxanthin for antioxidant function. This reduces the efficiency with which astaxanthin is used for pigmentation.
Limitations on dietary trace mineral content may explain disparity in shrimp coloration even when fed at the same astaxanthin level. This is especially true in stressful situations (e.g., changes in temperature, salinity and/or oxygen, handling, harvest, transportation, disease outbreaks) when the demand for antioxidant activity is higher.
Cut Feed Costs and Maintain Coloration
A cost-effective solution for improving shrimp coloration is to optimize your shrimp trace mineral nutrition program with Zinpro® Performance Minerals® (ZPM). In a recent research study, whiteleg shrimp were fed one of five diets. The control diet contained 75 ppm of astaxanthin without Zinpro Performance Minerals. The other four diets contained 25 ppm of astaxanthin and 25 ppm of canthaxanthin, along with various combinations of Zinpro® Availa® Zn, Zinpro® Availa® Mn, Zinpro® Availa® Cu, Zinpro® Availa® Fe and Zinpro® Availa® Se.
The research showed that by including Zinpro Performance Minerals, we can maintain a consistent SalmoFanTM score – a color measurement methodology recognized by the aquaculture industry as a standard for color assessment in salmon fillet and shrimp by DSM – and reduce lipid oxidation, despite cutting the amount of astaxanthin by two-thirds. The reduction of lipid oxidation highlights the role trace minerals play in antioxidant function.
On the other hand, reducing astaxanthin from 75 to 25 ppm in combination with canthaxanthin but without Zinpro Performance Minerals:
- Had no effect on lipid oxidation
- Reduced meat/shell redness values (a*)
- Reduced SalmoFan scores from 27 to 24.4 in 3 weeks
These results demonstrate that including Zinpro Performance Minerals in shrimp diets boosts shrimp antioxidant capacity after only three weeks, allowing astaxanthin to be diverted for pigmentation purposes instead of antioxidant functions. This allowed shrimp producers to save $66 per ton of feed.
Let’s Connect: Improve Shrimp Coloration
By improving antioxidant function with Zinpro Performance Minerals, we can also improve coloration so you can spend less money on feed and earn more from your meat. To learn how you can include Zinpro Performance Minerals in your fish and shrimp diets, contact your Zinpro representative today.