1. their role and production requirements
Rotifers
their role and production requirements
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2. Live food aquaculture training course
Reproduction
Mass production
Size
Mobility
Tolerance
Bio-encapsulation
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3. Live food aquaculture training course
Life cycle
B. plicatilis
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4. Rotifer production – optimal culture and enrichment conditions
Tank: Any Size/Shape (2-6 m3)
Temp.: °C (Preheated Water/Heat Exchange)
Salinity: ppt
Oxygen: 5-7 ppm (Pure Oxygen)
pH:
NH3/NH4+: < 10 mg/l
NH3: < 1 mg/l
Water: Filtered (1 m), UV, Chlorinated/Neutralized
Aeration - Reasonably Strong - Airstones
Illumination: Low Light Conditions
Floc traps
Batch Culture: 3-5 days
There are several critical conditions that have to be met in order to guarantee rotifer production and failure to achieve this can lead to stock crashes which without alternative food sources for the larvae can have serious impact on juvenile production.
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5. Rotifer production in 3m3 tanks
The second link of the live food chain is the rotifer. Here we see a typical production facility operating on a 4 day batch culture cycle.
A hatchery producing 5 million juveniles per year will require approximately 2-4 billion rotifers per day for consumption by fish during the larval rearing periods.
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6. Low density rotifer culture
Sea bream
General assumptions
1) Av. daily rotifer consumption/m3 larval volume (M) 10
2) Rotifer production volume/100M daily production (m3)
1,5
3) Period of rotifer feeding (days) 20
4) Culture Selco needed per 100M rotifers produced (kg)
0,2
5) Culture Selco price (drs/kg)
11234
Annual production target (2g juveniles)
No of larval batches 5
Initial larval rearing vol (m3) 62
123
185
308
Daily rotifer requirement (M)
615
1.231
1.846
3.077
Rotifer production volume (m3) 9 18 28 46
No of 2.8m3 tanks needed 3 7 16
No of 4m3 tanks required
Total rotifer production volume (m3) 8 45
Total Culture Selco requirement (kg)
246
369
Requirements
Cost of Culture Selco (Mdrs/yr)
1,38
2,77
4,15
6,91
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7. Rotifer culture using algae
excellent results with algae but expensive
time consuming (culture of algae + counting)
availability of algae
quality of the rotifers dependent on quality of the algae
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8. Rotifer culture using algae and yeast
variable results in rotifer survival depending on the quality of algae and freshness of the yeast
unexpected mortalities (total crashes) due to lack of standardisation
variability in rotifer quality (nutrition, microbiology)
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Batch culture of rotifers on algae and yeast
Culture period
6-10 days f e d i n g
harvest
drain culture water
Re-inoculation
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10. Medium density rotifer culture
Sea bream
General assumptions
1) Av. daily rotifer consumption/m3 larval volume (M) 10
2) Rotifer production volume/100M daily production (m3)
0,4
3) Period of rotifer feeding (days) 20
4) Culture Selco 3000 needed per 100M rotifers produced (kg)
0,20
5) Culture Selco price (drs/kg)
Annual production target (2g juveniles)
No of larval batches 5
Initial larval rearing vol (m3) 62
123
185
308
Daily rotifer requirement (M)
615
1.231
1.846
3.077
Rotifer production volume (m3) 2 7 12
No of 2.8m3 tanks needed 3 16
No of 4m3 tanks required
Total rotifer production volume (m3) 8 28 45
Total Culture Selco 3000 requirement (kg)
246
369
Requirements
Cost of Culture Selco (Mdrs/yr)
0,00
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11. Rotifer growth comparison CS v’s CS3000
Here we can see the typical growth curve of Culture selco 3000 against it predecessor the simple culture selco.
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12. Specific Growth Rate in MD batch culture
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13. Live food aquaculture training course
Method of determining rotifer growth and condition– mean specific growth rates
SGR = ln (Final Number)-ln (Initial number)
No. of days of culture
ln = natural log
Useful for:-
Following feeding experiments
Quantitatively assessing culture stability
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14. Rotifer production methodologies Culture Selco 3000 and O2
Rotifer production methodologies have improved over the years from an algae and yeast based diet which can if not carefully used give unpredictable results to improved culture diets which were less dependant upon algae to ensure continuation.
Today a new generation of diets enable culture densities of 2000 rotifers per mill to be achieved over a 4 day cycle. These densities however require continuous supplies of O2 and algal requirement in mass cultures is unnecessary
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15. Live food aquaculture training course
Rotifer Production
M: Masters
A: Culture (2-6 m3)
B: Inoculum (500 R/ml)
C: Enrichment
( R/ml)
Larval Tanks M M2 A
30%
70% B C
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16. Live food aquaculture training course
Culture Selco 3000 strategy
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17. Traditional rotifer batch culture
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18. High density rotifer production system
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19. Live food aquaculture training course
Rotifer harvesting
Rotifers should be harvested either from culture or from enrichment in a manner to ensure that they are well rinsed of metabolites, detritus and ciliates prior to their introduction to the larval rearing tank.
This should be done in as gentle a manner as possible to avoid rotifer loss or mortality. Generally this is done in a manual way but this automated system seems to be effective and is labour saving.
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20. Harvesting of rotifers
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21. Live food aquaculture training course
Transfer of rotifers
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22. Live food aquaculture training course
Recent work in Belgium have taken high density culture one step further.
Here recirculation systems and protein skimmers, in association with novel filters enable rotifer cultures to reach and be maintained at densities over 5000 per ml for prolonged periods of time.
This one M3 system can produce 2 billion rots per day for a production unit.
Savings such as these are beginning to play a significant role in the financial viability of the maturing bass and bream industry.
Recirculated ultra-high density rotifer culture ~5000 rotifers + /ml
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23. Live food aquaculture training course
Commercially available rotifer and artemia cultivation and enrichment products
A number of commercially available cultivation and emulsion type enrichment diets are available together with products that for Artemia are capable of altering the microbiological characteristics of the hatching and enrichment environments
This development both provides the farmer with custom nutritional packages and helps to deduce the possibility of disease that may be introduced through the live food chain.
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24. Fatty acid enrichment levels in Rotifers
I shall not dwell upon the specifics of enrichment levels of live food organisms as it is complex and lengthy.
However this table clearly shows that while algae enrichment alone does provide a variety of essential fatty acids and the profile of enrichment is affected by the species used the levels of enrichment of critical fatty acids obtained are inferior to those obtained by the use of commercial enrichment diets shown earlier
Consequently irrespectively of the production system employed bream and bass hatcheries routinely enrich rotifers with commercial preparations to ensure optimal nutritional conditions for the larvae.
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