Effects of temperature and starvation time on the pattern and rate of loss of essential fatty acids in Artemia nauplii previously enriched using arachidonic acid and eicosapentaenoic acid-rich emulsions

Artemia nauplii enriched for 18 h using six emulsions with widely differing essential fatty acids levels were subjected to starvation for 24 h at 4, 12, and 20 degrees C, Fatty acid profiles were monitored after 12 and 24 h at these temperatures and analysed by a two-way analysis of variance (ANOVA) to investigate the effects of temperature, time and the interactions of both factors on the fatty acid changes observed in the disenriched nauplii. Docosahexaenoic acid (DHA) levels decreased to less than half their initial value after 24 h starvation, Eicosapentaenoic acid (EPA) and arachidonic acid (AA) were also catabolized, although in a lower rate than DHA, after 24 h. (n - 3)/(n - 6) ratios remained relatively unchanged. Starvation period was the factor that affected the fatty acid profile to a greater extent than the temperature used, although the loss in essential fatty acid was generally more rapid at higher temperatures. The adjustment of daily ration and feeding frequency of enriched Artemia nauplii to meet larval requirements is recommended in order to prevent disenriched live-prey in the rearing tanks. (C) 1998 Elsevier Science B.V. All rights reserved.