Date: 19 August 1998 16:38
To: BRINE-L@UGA.CC.UGA.EDU
COMMENTS 1:
Here's an enrichment diet that has worked great for me, it's:
5 parts cod liver oil, to 1 part egg yolk, to 94 parts water;
put this in a blender for a while and feed it at 160ml/100L.
Daniel <dplaw@fullcomp.com.au>
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COMMENTS 2:
I haven't been looking at what brine shrimp are enriched with, so much as how they are enriched. Let me give you some background. Brine shrimp nauplii are commonly enriched with one or more species of live algae in larger-scale operations. The algae are usually selected based on fatty acid content. Eicosapentaenoic acid (EPA, 20:5n-3) and
docosahexaenoic acid (DHA, 22:6n-3) are usually the fatty acids
selected for marine fish. Enrichment is usually accomplished by
mixing the algae and nauplii in a vat for 8-24 hours, allowing the Artemia to fill their guts with the algae. Then the enriched Artemia are fed to fish, hopefully before they metabolize the fatty acids.
The question we were interested in was, does Artemia always eat both
species of algae, given in the enrichment mix? We have found
that the answer is: not necessarily. Differences in size, motility
and density of different algae in the mix make them more or less
susceptible to predation by Artemia. For example, we paired Isochrysis (small cells, weakly motile) with Tetraselmis (large cells, strongly motile), which creates a great fatty acid profile if Artemia eat both species. However, Artemia cleared large amounts of Isochrysis and virtually no Tetraselmis.
So, we recommend that each batch of Artemia be enriched with only one product. Fine-tuning of the fatty acid profiles can be made by
feeding specific numbers of Artemia from each enrichment treatment to the fish. I know, it seems obvious, but to our knowledge this question hadn't been dealt with before.
As for off-the-shelf enrichment products, my experince is quite
limited. The only one I have experience with which is cheap, easy and
useful in boosting fatty acids, is a product called Algamac, which is
spray-dried heterotrophic algae Schizochytrium sp. from Aquafauna
Bio-Marine, Inc. It comes in powder form, and you just whizz it up in
the blender.
Laurel Ramseyer <Laurel.Ramseyer@noaa.gov>
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COMMENTS 3:
The enrichments come in two general forms, a dry powder, and a pre-emulsified oil type liquid. The powder type is usually a blend of algal cells that are high in HUFA's. Sanders, Aquafauna/Biomarine, and Salt Creek products all come to mind.
The liquid enrichments are generally a bit more expensive than dry ones, but usually are higher in total fat and lipid content. They also might contain vitamins, carotenoids, and proteolytic enzymes. However, not all enrichments are equal. Sanders, INVE, Salt Creek and others, make fine liquid enrichments. A note on liquids, when inquiring about these enrichments, ask about the moisture content, some may include up to 40% water.
Dave Kuehn
Sanders Brine Shrimp Co.
Ogden, UT
801.393.5027
<davidk@sandersbshrimp.com>
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COMMENTS 4:
Based on experiments done here, I recommend ALGAMAC 2000 for Artemia enrichment. It is easy and clean to work with, and it gives very good results when both EPA and DHA are required.
Yoram Hoffman
Ardag LTD
POB 1742, Eilat
88116
Israel
tel: 972-7-6335111
fax: 972-7-6377901
email: yorhof@hotmail.com
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COMMENTS 5:
AlgaMac is a very good product as it is a whole spray dried cell, so it
should give everything the fish needs. As to the emulsion enrichments, we have tried pretty much all of them and have to say thet they are all fine. They enrich the Artemia and then the fish eat the Artemia, and we don't really see any difference in growth, survival etc. I would go with the cheapest.
Also what species of Tetraselmis were you using; we have T. suecica and it seems to be totally immobile. It grows great in the algae bags but as soon as you turn the air off it sinks and forms a big lump at the bottom.
Brendan Gara <Bgmannin@aol.com>