Phospholipids in Atlantic cod (Gadus morhua L.) larvae rearing: Incorporation of DHA in live feed and larval phospholipids and the metabolic capabilities of larvae for de novo synthesis
Year: 2015
Type: dissertation
Abstract: 22 An increasing number of studies suggest that DHA associated to dietary phospholipid (PL) 23 are better metabolically available for fish larvae. Knowledge on how to increase DHA levels 24 in the major PL classes of the live feed are needed. Brachionus Cayman was cultured in 25 conical fibreglass vessels, enriched with commonly used commercial diet Multigain or DHA 26 Selco (DSelco) in flat bottom vessels at 20 oC. The changes of DHA content in the PL of the 27 rotifers through enrichment and through a starvation phase post-enrichment were investigated 28 in order to define an appropriate enrichment time and to test the stability of DHA post29 enrichment. The different dietary non-HUFA (non-highly unsaturated fatty acid) composition 30 of DSelco (25.1 % SFA, 32.1 % MUFA) and Multigain (40.7 % SFA, 2.11 % MUFA) allowed 31 an evaluation on how SFA and MUFA might affect the efficiency of DHA enrichment of 32 phospholipid in the rotifers. Rotifer samples were collected at 0 h, 1 h, 2 h, 4 h, 8 h, 12 h and 33 24 h after initiation of enrichment. Total lipid (TL) and the fatty acid composition in TL, 34 phosphatidylcholine (PC) and phosphatidylethanolamine (PE) of rotifers and enrichment diets 35 were analysed. The highest DHA levels in PC (23.0%) and PE (16.5%) in Cayman were 36 found after 24 h enrichment with Multigain, and levels were far higher than obtained earlier. 37 The enriched DHA was stable at 10 oC for at least 24 h post enrichment under starving 38 conditions (p>0.05), whereas a significant (p<0.05) decrease of DHA was observed during 39 starvation at 20 oC. In order to obtain high DHA levels in PC and PE in rotifers, the 40 enrichment time is suggested to be at least 24 h to maximise the efficiency of DHA 41 enrichment in PL and the enrichment diet should have a high DHA content. The feeding 42 rations should be low to reduce the total lipid contents of the rotifers. The overall results 43 allowed us to propose a hypothesis that 18:1n9 can inhibit DHA incorporation through 44 competition whereas 16:0 can facilitate DHA incorporation into PL. The hypothesis needs to 45 be further tested. 46
Source: BIBSYS Brage (BIBSYS (Norway))
Author: Keshuai Li
Language: English
Subfield: Aquatic Science
Domain: Life Sciences
SDGs: Life below water, Zero hunger
Open Access status: green
OpenAlex ID: W2478484886