Function and metabolism
Total stigmasterol (1 a)
and cholesterol (1 b) accumulated by spat after 33
days of feeding with 0%,
3%, 10% and 20%
of emulsion per algae DW
as a function of the total
stigmasterol and cholesterol
added.
Discussion
Good spat growth obtained m the experiment suggests that the algal
mixture provided necessary nutrients despite lacking cholesterol, once
considered essential. Individual WW, FW, DW and OM contents showed
that the emulsion had no effect on the growth of the reared spat.
The relative sterol composition of the spat was significantly influenced
by the artificial diet composition after 7 days of supplementation. The
relative differences of sterol composition were maintained along the experiment. These changes in sterol composition of the spars fed with
emulsion showed that sterols incorporated in emulsion were ingested,
digested and accumulated by spat. Theses results confirmed that emulsion can be used to deliver essential lipids (Coutteau et al., 1996; Caers
et al., 1998, 1999).
The polynomial relationship between sterol added via emulsion and accumulated sterol amounts in the spat indicated the ability of the oysters
to accumulate sterols from the emulsion until saturation (not reached
in that experiment). An increasing percentage of emulsion in the diets
resulted in a decreasing accumulation rate of sterols from emulsion.
Emulsion sterol accumulation rates were much lower than algal sterols when
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