Salmonid pigmentation : Dynamics and factors of variation. A review

Abstract

For less demanding animals, such as two year-old cattle winter Carotenoid pigments are wide-spread in fish. These liposoluble pigments colour the fish teguments and different tissues or organs yellow, orange or red (in particular muscles and gonads). These pigments occur in fish in different forms and various states. Carotenoid fixation by salmonids depends on many factors linked in part to the fish and to the food. Fish are unable to synthesize carotenoids de novo and must obtain them from food. In nature, the red colour of trout and salmon comes from a food rich in invertebrates, the dominant pigment of which is astaxanthin. In intensive salmon rearing, it is necessary to complement or supplement diets with various raw or synthetic products. However, the stability of such products in food is questionable. Indeed the carotenoid structure itself makes these compounds very labile. Moreover, the duration and conditions of storage may bring about slight modifications which can hardly be anticipated owing to the diversity of feed formulae, manufacture and delivery conditions.