From: madigan.stephen@wpo.pi.sa.gov.au
To: AQUA-L@listserv.ifmt.nf.ca
BIOCHEMICAL PROPERTIES OF DUNALIELLA SALINA.
QUESTION:
I am interested in any information regarding the biochemical composition of the alga Dunaliella salina. For example, protein content, carbohydrate and lipid profiles etc. etc.
Stephen Madigan
Aquaculture
South Australian Research and Development Institute
Aquatic Sciences
<madigan.stephen@pi.sa.gov.au
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ANSWER:
We ourselves have done very little work with D. salina, but quite a
bit with D. tertiolecta. Our research application has been chiefly to
bivalve feeding. As such, D. tertiolecta has proven to be a
relatively poor food. We have attributed this poor food quality for
bivalves to lipid deficiencies in Dunaliella; I expect that the
qualitative deficiencies apply to D. salina as well, since these
deficiencies are characteristic of all chlorophyte algae.
Chlorophytes produce no fatty acids longer than 18 carbons. Oysters
and scallops (and maybe some clams) are unable to elongate 18-carbon fatty acids, and require 20- or 22-carbon fatty acids for membrane synthesis. In addition oysters and scallops require certain sterols in the diet for
reasons similar to the fatty acid story. We did analyze
(collaborators at the University of Maryland did the analysis) D.
salina for sterols and found none of the required compounds. As
bivalve feed, Dunaliella has clear deficiencies, although there is
some potential to use Dunaliella as a protein and carbohydrate source
in a mixed diet including high-lipid (and the right lipid) algae.
From a practical standpoint, we have found D. tertiolecta to be a very
good feed for growing rotifers, although rotifers grown on Dunaliella
alone are again deficient in lipids when fed directly to larval marine
fish. We enrich these rotifers with T-ISO and Nannochloropsis before feeding, or, more recently, have adopted green-water culture
techniques for fish larvae with daily inputs of rotifers, T-ISO, and
Nannochloropsis.
Gross biochemical profiles of D. tertiolecta are published in several
of our articles. I will send reprints to you if you do not have them
already (I will need your mailing address). Also look into the work
of Ami Ben-Amotz in Israel; he published a great deal on Dunaliella,
including several articles on D. salina. I don't know if any of these
articles include general biochemical profiles, though.
Gary Wikfors
Gary.Wikfors@noaa.gov
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