Effects of β-carotene source, Dunaliella salina, and astaxanthin on pigmentation, growth, survival and health of Penaeus monodon

We report the results of controlled feeding trials on the tiger shrimp, Penaeus monodon (Fabricius). The desired colour was obtained by feeding a diet supplemented with astaxanthin (50 p.p.m) for 7-8 weeks before harvest. Similar coloration was achieved, however, by including in the feed an algal material (Dunaliella salina) that contains carotene but no astaxanthin. Feed containing carotene at 125 p.p.m also gave the required coloration at 7-8 weeks, whereas the same results was obtained after only 5-6 weeks when feed containing 175 p.p.m beta-carotene was used. Irrespective of whether the shrimp were fed astaxanthin or beta-carotene, the main carotenoid accumulation was astaxanthin, in free and esterified form, showing that P. monodon has the metabolic ability to convert beta-carotene into astaxanthin. The supplementation with beta-carotene or astaxanthin had no significant effect on growth, average final weight, survival rate or feed conversion ratio, nor on the immune response of the shrimp in terms of production of haemocytes phenoloxidase in the cytoplasmic granules of the haemocytes, microbial clearance ability and resistance to infectious diseases. This is a highly significant development for commercial aquaculture, because it shows that supplementing diets with beta-carotene can achieve the same result as doing so with much more expensive astaxanthin.