Growth, survival and fatty acid composition of freshwater crayfish (Astacus leptodactylus) juveniles fed enriched daphnia magna as an alternative to Artemia

Abstract

This experiment was conducted to investigate the effects Daphnia magna enriched with lipid emulsions as an alternative to Artemia, on growth, survival rate, and fatty acid composition of freshwater crayfish (Astacus leptodactylus Esch. 1823). The four treatment groups were (a) unenriched Artemia (UEA), (b) unenriched D. magna (UED), (c) D. magna enriched with redpepper emulsion (DER), and (d) D. magna enriched with anchovy oil emulsion (DEA). All tests were carried out in triplicate for 30 days. The crayfish (mean weight 0.12g) were fed ad libitum once daily. At the end of experiment, the highest eicosapentaenoic acid, 20:5n-3 (EPA) level was found in the DEA group (5.77%). The highest DHA (docosahexaenoic acid, 22:6n-3) level was found in the DER group (2.73%) which was statistically similar to the DEA group. In addition, high n-3 HUFA (high unsaturated fatty acid) levels were detected in enriched D. magna groups with emulsions. However, high EPA levels in enriched D. magna groups with emulsions were not reflected in crayfish tissues, but DHA level was reflected in crayfish tissues fed with anchovy oil emulsion. The crayfish fed with D. magna showed similar growth to that of the Artemia fed groups. The growth of the enriched D. magna groups did not differ.