Shamsudin, M.L.
Abstract:
Microalgae have an important role in aquaculture as live food for larval stages of many species of crustacean and fish, as well as for all stage of bivalves and as food for the zooplankton (rotifers, copepods, brine shrimp), which are eventually fed to late larval and juvenile fish and crustacean in hatcheries. The total ash, chlorophyll, phaeopigment, lipid and fatty acid contents of microalgae (the diatoms; Chaetoceros calcitrans, Chaetoceros socialis, Chaetoceros malaysia, Chaetoceros sp and the Chlorophyceae Tetraselmis sp., Chlorella sp., Nanochloris sp.) used in aquaculture were studied. The axenic laboratory cultures were grown in f-2 medium, while outdoor cultures were grown in a commercial medium designed for optimum nutrition in tropical aquaculture operations. Fair amounts (2-10 per cent of total fatty acids) polyunsaturated fatty acid (20:5n-3) (eicosapentaenoic acid) were present in the diatoms; trace amounts were also found in Tetraselmis. Lipid contents were three to five times higher than chl a. There was and increase with culture age in the relative proportion of total C18 and C20 fatty acids. The algae contained the omega3-polyunsaturated fatty acids (PUFA) necessary for the growth and survival rate of the prawn larvae. Chaetoceros malaysia grew well under the conditions of temperature and salinity in the hatchery.
(Fisheries and Marine Science, Univ. Pertanian Malaysia Terengganu, Mengabang, Telipot, Kuala Terengganu, 21030, Malaysia)
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