摘要：Thraustochytrids are marine heterotrophic straminipilans that have recently gained attention due to their capability to produce large amounts of lipids and especially to their utility as an alternative source of the omega-3 polyunsaturated fatty acids (PUFAs).Two identified thraustochytrids ( Thraustochytrium sp. SB04 and Schizochytrium sp. SB11) isolated from senescent fallen mangrove leaves in Subic Bay, Philippines were further studied for their carotenoid contents and potential as alternative fish feed for Oreochromisniloticus (Nile tilapia). Their optimized culture conditions for biomass and total fatty acid production have been reported recently. In this present study, the carotenoid contents of these two isolates were analyzed via Thin Layer Chromatography (TLC) of acetone extracts of fresh and oven-dried cells. Their pigments present were identified through their Rf values. Thraustochytrium sp. SB04 showed astaxanthin monoesters, astaxanthindiesters, astaxanthin free, and echinenone; whereas Schizochytrium sp. SB11showed echinenone, lutein, astaxanthin monoesters, and astaxanthindiesters. These identified compounds were recently reported to have antioxidant properties, anticancer, and immunomodulatory effects to humans. Further, astaxanthin is a red pigment common to many marine animals and are used as food coloring and feed additive for poultry and aquaculture industry. Further, when dried cells of the mass-produced isolates were used as feed supplements for the growth of O. niloticus , the growth yield of the fish showed a significant difference (p<0.05) when compared to commercial fish feeds. Results of this study showed that thraustochytridcells can be used as source of naturally occurring carotenoids and as promising alternative fish feed to O. niloticus
