Aquaculture Values Astaxanthin
Astaxanthin is best known for its commercial use in the aquaculture industry. In its pure, synthetic form, fish farmers use it to provide the pinkish-red color to salmon, trout and crustaceans such as crabs, krill and shrimp. The ruddy pigmentation of the fish flesh brought about by astaxanthin is considered an important consumer criterion of quality. Wild fish acquire their characteristic salmon flesh color from astaxanthin found in the single-celled organisms they eat.
The fact that salmon cannot synthesize astaxanthin and must find it in their diet to maintain pink-colored flesh—and can reproduce only if astaxanthin is present in their diets—are indications of astaxanthin's necessity in these animals. [1]
Owing to the high demand for astaxanthin in animal feed, particularly aquaculture and poultry (for egg yolk color enhancement), astaxanthin is chemically synthesized on a large scale. The worldwide market is estimated at about $185 million in 2000 and is growing rapidly.
Astaxanthin is found naturally in certain plants. The yeast Phaffia rhodozyma and the microalgae Haematococcus pluvalis are the only microorganisms able to biosynthesize astaxanthin in appreciable yields and have recently gained considerable interest as sources of natural astaxanthin. Among the natural sources, H. pluvalis contains the highest level of astaxanthin, which exists mainly as esters of various fatty acids.
Astaxanthin occurs in several different forms depending on its precise molecular makeup. Many laboratory studies use synthetic astaxanthin. Although similar in action, one difference noted between the two forms is that natural astaxanthin tends to produce a higher pigmentation in rainbow trout compared to synthetic astaxanthin provided at the same dietary concentration. [2] Other nutrients contained in natural sources, as well as subtle chemical differences between the two forms, may also account for nonidentical activities.
Yousry Naguib
References
1. Johnson EA, An G-H. Astaxanthin from microbial sources. Critical Rev Biotechnol 1991;11:297.
2. Bowen, et al. Aquasearch technical report TR.2102.001. Aquaxan HD algal meal use in aquaculture diets: enhancing nutritional performance and pigmentation. 1999.
|
|
