The carotenoids of wild and blue disease affected farmed tiger shrimp (Penaeus monodon, Fabricus).

1. The main carotenoids in wild Penaeus monodon exoskeleton were astaxanthin di- and mono-esters, astaxanthin, and beta-carotene. 2. Wild P. monodon exoskeleton contained on average 26.3 ppm total carotenoid; normally pigmented farmed shrimp had a similar concentration (25.3 ppm). 3. Exoskeletons of farmed "blue" P. monodon (i.e. blue-coloured, as opposed to the normally red-blue/black banded shrimp) contained significantly less total carotenoid (4.3-7 ppm). The only major carotenoid being astaxanthin. 4. Commercially available diets contained only trace quantities of canthaxanthin. 5. Nutritional deficiency with respect to carotenoids is suggested as the cause of blue disease in farmed P. monodon.