Studies on the enrichment of Artemia urmiana cysts for improving fish food value

Since no artificial feed formulation is yet available to substitute completely for Artemia, feeding Artemia cysts to young fish larvae still remains essential in commercial hatchery operations. The nutritional quality of commercially available Artemia strains is relatively poor in eicosapentaenoic acid (EPA, 20:5n−3) and docosahexaenoic acid (DHA, 22:6n−3), two major determinants of fish food value and also the price of Artemia cysts. It is a common practice to enrich these Artemia cysts with emulsions of marine oils. In the study reported, fatty acids of Artemia urmiana cysts were studied by GC, both before and after their enrichment with fish oil. Decapsulated cysts of A. urmiana were dried for 24 h at 60 °C, fatty acids were extracted with diethyl ether, converted to the methyl esters of fatty acid (FAME) by methanolic KOH (2N), and the esters were extracted with n-heptane. FAMEs were injected to GC for the determination of the composition and quantity of fatty acids. In the next stage, A. urmiana decapsulated cysts were enriched with fish oil to increase its EPA and DHA fatty acid levels and analysed by GC. The result demonstrated that this enrichment method brought about an increase in the levels of EPA from 159 to 195 g/kg and DHA from 6 to 84 g/kg.