The role of lipids during embryonic development of the euphausiids Euphausia pacifica and Thysanoessa spinifera

Abstract

To understand the role of lipids during early embryogenesis, major lipid classes together with individual fattyacid and sterol composition were determined in embryos from multiple developmental stages of the euphausiids Euphausia pacifica and Thysanoessa spinifera. Average lipid content in embryos of E. pacifica and T. spinifera from the earliest stage (multicell) were 4.45 and 3.69 mg embryo 21 , respectively. During development, the lipid content decreased at similar rates in the embryos of both species. In contrast to many crustacean eggs, phospholipids were the dominant lipid class in all embryonic stages, with decreasing concentrations seen during development. Individual fatty acids and sterols showed selective utilization during early developmental stages. The dominant fatty acids were 16:0 and 16:1v7 and 20:5v3, with most polyunsaturated fatty acids preferentially metabolized throughout early stages. An exception was 22:6v3, which remained near constant through all stages. Cholesterol was the dominant sterol (.82% of total sterols) in embryos, with only minor changes during development. The appearance of algal sterols and fatty alcohols, including phytol, in T. spinifera embryos suggests that considerable amounts of algal lipids are directly allocated to eggs during vitellogenesis. Despite the substantial changes in lipid amount and composition during embryo development, the presence of phospholipids as the dominate lipid store acts to moderate changes in egg-sinking rate for both species until the late (early and late limb-bud) stages of development.

Quantitative significance of n-3 essential fatty acid contribution by heterotrophic protists in marine pelagic food webs

“…The effects of food quality on the growth, reproduction and neonatal development of copepods have been studied extensively (e.g. Jónasdóttir et al 1995, Jónasdóttir & Kiør-boe 1996, Koski et al 1998, Tang et al 2001, Turner et al 2002, Tang & Taal 2005, Ju et al 2006. It has become apparent that both the quality and quantity of food in the diet affect copepod production, and ultimately, production at higher trophic levels.…”

Embryos of an Antarctic zooplankton require anoxia for dormancy, are permeable to lipophilic chemicals, and reside in sediments containing PCBs

“…poppei , because zooplankton embryos are preloaded in utero with chemicals that bioaccumulate in the food web 10 , 11 and sit for years in bottom sediments where passive accumulation of chemicals continues 9 , 12 . Lipid stores are mobilized to support early zooplankton development 13 – 15 , and the impacts of lipophilic chemicals manifest when they are released as lipid stores are used 16 – 18 . Given this, it is surprising that little research has been conducted on the impacts of anthropogenic chemicals on egg bank viability.…”

Scoping Intergenerational Effects of Nanoplastic on the Lipid Reserves of Antarctic Krill Embryos

“…Future work exploring the impact of nanoplastic on krill embryo energy reserves should therefore investigate differences in protein composition to complement our exploration of nanoplastic impact on lipid reserves. This may be particularly important since Yoshida (2011) determined that the use of lipid by Antarctic krill during embryonic development is less than observed for other euphausiids (Ju et al, 2006), further supporting protein sources as a main reserve during development. To build further on our results, since embryonic development accounts for <4% of the metabolic requirements of all non-feeding stages, and therefore most energy reserves are passed on to larvae for development through to the first feeding stage (Quetin and Ross, 2003), potential effects of altered energy resources should be explored in the larva stage of krill too.…”