Abstract. The interactions of astaxanthin and vitamin A on the growth and survival of Atlantic salmon, Salmo salar L., during the first-feeding period were examined using semi-purified diets. Alevins, with a mean initial weight of 0.18g, were fed diets supplemented with 0, 20 and 40 mg astaxanthin/kg dry diet and 0, 750 and 1500 μg vitamin A/kg dry diet for 20 weeks. The weights of the fish were recorded throughout the experimental period and carcasses were collected for proximate composition, vitamin A and astaxanthin analyses at the beginning and end of the experiment. The feeds were analysed for proximate composition, vitamin A and astaxanthin levels.

No interaction between astaxanthin and vitamin A was found in relation to the growth, survival or vitamin A content of the fry. Astaxanthin was found to strongly influence the growth, survival and vitamin A concentration in the fish. Poor growth and low survival rates were observed in groups fed diets without astaxanthin, including the group fed a diet with sufficient vitamin A. The results indicate both a provitamin A function of astaxanthin and a specific function of astaxanthin. Astaxanthin was found to be essential to alevins during the first-feeding period.