Date: 29 Aug 97
From: Brendan Gara/SFIA <Brendan_Gara/SFIA@fc.uhi.ac.uk>
To: aqua-l@killick.ifmt.nf.ca
QUESTION:
I am currently setting up a rotifer culture system to provide live feed for marine fish larvae. I will need to harvest about 60 million rotifers per day during the larval rearing stage. The system I used previously relied heavily on algae (Nanno sp. & T-Iso) and bakers yeast, followed by an enrichment with AlgaMac. Rotifer production was fairly low (200 rots/ml max) and in 80 litre containers. This year I would like to use a more efficient system and also one that could be scaled up easily, to a larger industrial scale. I have read the papers describing the Culture Selco method and would like to try it. Has
anybody got any experience with this method and what is the efficiency/problems with it- are people using extra enrichments after culture eg other Selco products? Also, is anybody using the artificial diets developed at IFREMER in the 1980's as these seem fairly inexpensive. If algae are going to be necessary, the maximum production from our system would be around 100 litres per day. Any suggestions/advice would be greatly appreciated.
Brendan Gara
Seafish Aquaculture
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Date: 19 Sep 1997
From: COUTTEAU Peter <p.coutteau@inve.be>
To: "'AQUA-L@killick.ifmt.nf.ca'" <AQUA-L@killick.ifmt.nf.ca>
ANSWER:
As the producers of Culture Selco INVE AQUACULTURE would like to present some information on our Selco products for rotifer culture and enrichment.
As you correctly state it can be very difficult to obtain larger
numbers of rotifers using the algae and yeast method not only due to
possible nutritional restraints of the algae/yeast used but also due
to the vast quantities of algae implied in an industrial scale
production of rotifers.
Culture Selco on the other hand is a dry and unique off the shelf
diet to culture rotifers with a high nutritional value without using
algae and/or baker's yeast. And you are sure that the nutritional
quality is constant - which you can never be sure of when using algae.
The product is simple to use as you just need to blend it well with
water (kitchen blender or even better an industrial blender/mixer) and
then feed it to the culture.
You state that your output is around 200 rotifers/ml - We have for
several years been supplying Culture Selco to the commercial
hatcheries in Europe and our clients who have to produce many billions
of rotifers daily are achieving outputs (on industrial scale) between
600-1300 rotifers/ml after 4-5 days of culture depending on the
culture system used.
The Culture Selco method however does not exclude the use of algae
completely since we recommend to restart the production cultures from a master culture cultured on algae after ca. 7 production culture
generations for security reasons. This in order to avoid culture
crashes due to for instance contamination of protozoa.
As for enrichment - It is well documented that the diet of marine fish
and crustacean larvae has to be supplemented with essential nutrients.
Most important in this respect are the fatty acids of the marine type
(n-3 HUFA'S: EPA: 20:5n-3 and DHA 22:6n-3). Other important components are phospholipids, amino acids, vitamins and carotenoids. Even though you reach good levels of n-3 HUFA'S and for example vitamin C with Culture Selco you should enrich the rotifers afterwards for optimal results and INVE AQUACULTURE has a range of enrichment products to choose from according to your preferences, the culturing system applied and of course the fish species you are cultivating.
DHA Selco: A liquid self-emulsifying Selco with a modified DHA/EPA ratio due to use of special oils. Also available with the DC
application (Disinfection Continuously) designed especially for
Artemia enrichment.
Super Selco: A super concentrated form of Selco achieving the
highest HUFA level in Artemia and rotifers. Also available with the DC application for Artemia enrichment.
Protein Selco: A dry enrichment diet designed especially for rotifers. The high protein level allows continuous growth of the culture during the enrichment period.
DHA Protein Selco: Incorporates all the good features of a high
protein, high HUFA enrichment for rotifers with a high DHA/EPA ratio especially important for very sensitive larvae of marine species. Can also be used together with Culture Selco on the first day of culture to increase the egg ratio of the rotifers and thus boost the culture.
More detailed information on instructions for use (culture system
set-up, feeding regime, physical parameters and enrichment strategies) can be provided on request.
Morten Deichmann, INVE Italia Srl.
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