Date: 18 August 1998
To: BRINE-L@UGA.CC.UGA.EDU
QUESTION:
Has anybody had any experience with decapsulated brine shrimp eggs? Is there any additional value in feeding decapsulated brine shrimp eggs to fry?
Simpson, Bill <Bill.Simpson@us.origin-it.com>
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COMMENTS 1:
Since we probably market more decapsulated cysts than any other company I will attempt to answer your question.
Decapsulated cysts (non-hatching variety) do not have to spend energy hatching, therefore exhibit a higher caloric (energy) content. Each species needs to be evaluated for their ability to digest the unhatched, decap cyst product. We know it works well for penaeid shrimp from PL4-5 onwards. The mysis and younger PL's lack the mandible power to break the membrane. It has also been proven to be highly acceptable to carp, catfish and several other freshwater species.
Certainly more work is needed to determine which species can benefit from this product. The cost advantage is that you are only purchasing "meat", as +/-35% of the weight of a tin of Brine Shrimp Eggs is the chorion (shell). It should be part of a feeding strategy if it works for your species and should save a person some $'s.
Howard W. Newman <BShrimp@aol.com>
INVE AQUACULTURE, Inc.
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COMMENTS 2:
We have been using and selling the decap for the past year. We have
recently been able to get the manufacturer to realize that there is a
market out there for their product by the tropical fish hobbyist. The best way to use it is let your newly free swimming fry eat the newly hatched brine shrimp for the first 3-7 days before switching to the decap. This allows the fish to get used to the smell and sight of the live nauplii first. I have used it on all my fry after the 3rd day. I have had great results using it with my fry and after a couple weeks start adding finely ground flakes. There are two ways to administer the decap. 1. you can just sprinkle it on the surface of the water - great for surface feeders, and 2. soak it for a minute or two in water and then it will sink. This method is best used with the bottom feeders and newly hatched fry that stay at the bottom for a few weeks.
Even sprinkling it over the surface, it will eventually soak up water
and begin sinking.
It is best kept in a dry cool place. The decap is made up from low grade cysts that wouldn't hatch to begin with and the manufacturer takes these non hatchable cysts and removes the shells, then dries them and puts them in packaging.
In price comparison to live brine nauplii, the decap is very cheap per
pound. With hatchable cysts now going for up to $75 a pound, one can get a pound of decap for under $20!
Kaycy <djhanson@calweb.com>
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COMMENTS 3:
Due to the shortage in GSL cysts, Inve is providing another source of Artemia cysts (RH cysts) which are sensitive to the standard decapsulation technique. An adapted decapsulation technique is developed for this new Artemia source, giving the same hatching
output as non decapsulated cysts (>90%). The description of the new
technique is under publication now and will be presented during the
aquaculture meeting in Bordeaux. Afterwards we can send you a copy of the abstract (including the technical procedure).
This new source of Artemia is showing a better separation compared to GSL cysts when non-decapsulated cysts are used. To optimise the
separation between cysts and nauplii, we suggest following technique
to the hatcheries:
1. When large hatching tanks are used, raise DO level to >10 ppm by
using pure oxygen
2. Flush the outlet tube shortly
3. Put off the light and aeration and let separate for 5-10 min
4. Flush unhatched cysts
5. Let separate for 10-15 min
6. Harvest 25% of the volume (half valve opening to prevent vortex
formation)
7. Separate another 15 min
8. Harvest next 25% of the volume
In this way you should get a very good separation of the nauplii.
Tania DE WOLF-R&D Aqua Division-Inve Technologies NV
Oeverstraat 7- B-9200 Baasrode, Belgium
Tel : +32-52-33.13.20 Fax : +32-52.33.45.31
e-mail : t.de_wolf@inve.be