Time kinetics of fatty acids changes in total lipids and phospholipids of A. franciscana following enrichment and starvation, with a main focus on docosahexaenoic acid (DHA)
Abstract
HUFA in PL has been considered to be easily digested by marine fish larvae, which will result in better growth, survival and development (e.g., pigmentation, stress resistance and gut maturation). As one of the most commonly used live preys in aquaculture, Artemia sp. contain low amount of highly unsaturated fatty acids (HUFA), especially of docosahexaenoic acid (DHA, 22:6n-3) in phospholipids (PL) even after enrichment. The objective of the present thesis is to study time kinetics of change in important HUFA in total lipid (TL), phosphatidylcholine (PC) and phosphatidylethanolamine (PE) of A. franciscana nauplii and juveniles following short-term enrichment, subsequent starvation and long-term cultivation, with a main focus on DHA.No DHA was found in PC and PE during the first hour of the short-term enrichment of Artemia nauplii. The content of HUFA did not accumulate in PC and PE during the first hour of enrichment, but significantly (p<0.05) increased in TL. After 1h, the content of HUFA in PC and PE increased gradually and the regression analysis showed that the content of DHA in PC and PE during short-term enrichment and following starvation, respectively, increased and decreased significant slower than that in TL. Moreover, relatively low content of DHA in TL was found during long-term cultivation of juvenile Artemia when compared with nauplii, whereas the content of DHA in PC and PE was similar. The contents of EPA and ARA in TL, PC and PE increased steadily during short-term enrichment, following starvation of nauplii, and long-term cultivation of juvenile Artemia. From the results we assumed that the accumulation of HUFA in PL during short-term enrichment of nauplii was probably due to fatty acids retailoring between PL and TAG, and an additional amount of DHA might be incorporated into PL through PL-synthesis pathway during long-term cultivation of juvenile Artemia.