Effect of aeration on the efficiency of Artemia enrichment with EFA-rich emulsion and liposomes

A commercial emulsion and EFA-rich liposomes have been used as Artemia nauplii enrichment products in a study designed to determine the effect of the aeration on the enrichment efficiency and its importance as a source of variability in the final naupliar fatty acid content. With this purpose, fatty acid profiles of nauplii enriched under uncontrolled aeration conditions were compared to nauplii enriched under different controlled aeration modes. Concretely, both emulsions and liposomes were tested in six enrichment series resulting from the combination of three different airflows and two air diffusion systems. Moreover, the naupliar survival after the enrichment process was estimated since some mortality was previously recorded in liposome enrichments. The results revealed a small effect of aeration on both the EFA incorporation and naupliar survival in the emulsion treatment. However, liposome treated nauplii underwent the influence of the different aeration modes both in terms of EFA incorporation and naupliar survival. In general, the liposome enrichments showed the highest EFA incorporation when the enrichment procedures were carried out at low airflows. Besides, the use of airstones improved the enrichment efficiency at the lowest airflow, whereas this diffusion system produced a decrease of the EFA content in liposome enriched nauplii at the highest airflow. In spite of the unquestionable effect of aeration on the EFA enrichment in liposome enrichments, other concomitant factors must be acting in the process since variability still occurred even with the control of aeration.