Speculative Review of Possible Carotenoid Function in Fish

The subject of carotenoid nutrition in fish is reexamined on the basis of information concerning carotenoid function in microorganisms and ruminants. The protective action of carotenoids against photodynamic damage and the relation between β-carotene and bovine fertility are discussed. Tentative suggestions are made regarding the possible metabolic role of carotenoids during egg and larval development in fish. It is suggested that carotenoids may perform a biological role similar to that of α-tocopherol (as a naturally occuring antioxidant), protecting delicate tissues and reactive compounds from oxidative damage. Well-controlled trials will be required to clarify the role of carotenoids (other than for vitamin A activity and pigmentation) in selected fish and crustaceans.