LIVE FEED AKU3201 Principles of Aquaculture
Broodstock –> larvae -> fry -> fingerling -> juvenile Life cycle 2
Very small Extremely fragile Physiologically not fully developed Small mouth Still developing organ (i.e., eyes, chemoreceptors, digestive system) Larvae 3
Yolk sac for 3 weeks 4
Yolk sac for 3 days 5
6
8
9
Phytoplankton/ Microalgae Zooplankton Invertebrate Nematode Natural/Live food 12
Live Food 13
Microalgae 2-20 mikrometer Phytoplankton 14
Skeletonema
Pheaodactylum
Chaetoceros calcitrans
Chlorella
Dunaliella tertiolecta
Tetraselmis
General features of micro algae used in aquaculture
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31
High unsaturated fatty acids (HUFA) 1)Eicosapentaenoic acid (EPA; 20:5n-3) 2)Arachidonic acid (ARA; 20:4n-6) 3)Docosahexaenoic acid (DHA; 22:6n-3) Nutritional value 32
Food for: Bivalves Penaeid shrimp Fish Rotifer, Artemia Microalgae 33
Problem: Crash of algal culture Solution: 34
Rotifer 50 – 200 mikrometer Zooplankton 35
Brachionus plicatilis Euryhaline: able to tolerate wide range of salinities Suitable for crustaceans & fish Rotifer 36
L- type = mikron S- type = 93 – 179 mikron SS- type = 90 – 159 mikron
Small size & slow swimming velocity Suitable for fish that can’t ingest Artemia nauplii Possible to rear at high density Suitable for bioencapsulation/ enrichment Advantages 38
Brine shrimp (Artemia) 400m- 800 mikrometer 40
41 ADULT NAUPLII
Nauplii of Artemia most widely used food item Artemia 42
Able to tolerate > 70 ppt & up to 250 ppt. Why? Able to produce dormant eggs (cyst) = Diapause 43
44
Available in cysts Advantages? Place cyst in well-aerated seawater => hatch into nauplii after 24 hours Nauplii positive phototaxis 45
Artemia = filter feeder 48
49
Problems in obtaining steady supply of adequate quantities at appropriate times Hard to ensure the quality & quantity of natural food Nutritive value vary according to culture conditions Contamination Problems with live food 50
Axenic Artemia Hydration – Put cyst with water & aerate for 1 h Decapsulation – Disinfect using NaOH and NaOCl Stop reaction – Add Na 2 S 2 O 3 and wash with H 2 O
Other food
Egg custard
Tubifex Worm Blood worm
Mysis blood worm
Polychaete