REQUIREMENTS FOR CAROTENOIDS IN FISH DIETS

Carotenoids are among the most widespread and important pigment classe s in living organisms, and in marine animals, astaxanthin is the most commonly occurring red carotenoid. Carotenoids are vitamin A precursor s and are fundamental in photosynthesis and light protection in plants . Increasing attention has been drawn to a possible light protection, cancer prevention and immune enhancement by carotenoids in mammals. Re ported functions in fish range from a general enhancement of performan ce to specific functions in reproduction and metabolism. In this paper , we show that astaxanthin is essential for growth and survival of fis h and crawfish, and discuss this act in relation to the use of purifie d and semipurified diets in nutritional studies. The similarity in act ion of astaxanthin and canthaxanthin compared to cr-tocopherol (vitami n E) and retinol (vitamin A) suggests that these two carotenoids shoul d be listed among the fat soluble vitamins.