A Primer on Artemia

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A Primer on Artemia Biology and Production: 

A Primer on Artemia Biology and Production Chris Lawrence Brigham and Women’s Hospital July 2006

Overview: 

Overview Biology Production Application for zebrafish culture

Taxonomy and Distribution: 

Taxonomy and Distribution Artemia is a complex of sister species, collectively referred to as Artemia salina. Other species include A. franciscana, A. parthenogenetica Variation in size and nutrient composition World-wide, discontinuous distribution Temperate, subtropical, tropical zones Occur in ~500 natural salt lakes, man-made salterns, salinities from 70-250 ppt ~90% commercially produced cysts from Great Salt Lake, UT, USA

Life History: 

Life History Non-selective filter feeders of organic detritus, micro-algae, bacteria Animals undergo 15 molts (instars), larvae – adult (1-3 weeks) Adults employ dual reproductive strategy: Ovoviviparous – “good conditions” Oviparous - “bad” conditions

Schematic of Life Cycle: 

Schematic of Life Cycle Credit: U.S. Geological Survey

Cysts: 

Cysts Cysts encased in hard, protective shell Dehydrated 200-250 uM Credit: www.bohai-artemia.com

Decapsulated Cysts: 

Decapsulated Cysts Outer shell chemically removed Embryo enclosed in chorion 200-250 uM Credit: www.ebigchina.com

Hatching Nauplii: 

Hatching Nauplii ~20 Hours “Parachute”, larva hangs inside shell Chorion soon to be ruptured Credit: Carolina Biological Supply / Visuals Unlimited

Newly Hatched Nauplii (Instar 1): 

Newly Hatched Nauplii (Instar 1) ~20-24 hours No exogenous feeding Subsists on yolk-sac reserves 400-500 uM Credit: www.osc.mun.ca

Metanauplii (Instar 2+): 

Metanauplii (Instar 2+) 28-32 hours Begin exogenous feeding Gut tube 500+ uM Credit: www.ibss.iuf.net/course/images

Production: 

Production Hatching parameters Decapsulation Enrichment Cysts, nauplii, metanauplii Energetics

Hatching Parameters: 

Hatching Parameters Light – 2000 lux at surface, constant Temperature - 25-28ºC Salinity - 5-50ppt Density - 1-5 g/cysts per liter pH – 8.0-8.5 (1-2g/L NaHCO3 or CaCO3) Dissolved O2 - 0.6-2 mg/L *Operation outside “optimum” range has negative effect on energy content of animal

Decapsulation: 

Decapsulation Chemical removal of hard shell (cyst) Cyst dissolved in NaOH/Hypochlorite solution Storage at 7C in freshwater lasts up to 7 days, 3 months in hypersaline Advantages High energy/nutrition content Small size Digestible Bleaching “sterilizes” cysts

Enrichment: 

Enrichment Artemia (metanauplius on) are non-selective filter feeders Bioencapsulate them with Selco, microalgae, Spirulina, etc. Advantages Improves nutritional profile of metanauplii - HUFA/PUFA, Ascorbic Acid, etc. Disadvantages Time, labor Larger size, more difficult for small fish to capture

Cysts: 

Cysts Must be decapsulated Used directly, or stored for up to 3 months @4C in hypersaline Advantages Small size, high energy content, low labor input Disadvantages Not motile, sinking, deficient in free ascorbic acid

Nauplii: 

Nauplii Cysts (decapsulated or not) reactivated Hydration in 5-50ppt water (seawater) Hatch within 24 hours depending on environmental conditions Fed out immediately to fish Advantages High nutrient content, motile, digestible, visible Disadvantages Deficiency/variation in HUFA/PUFA, vitamins, minerals

Metanauplii: 

Metanauplii Instar 1 nauplii molt into instar 2 metanauplii 24-28 hours post set-up Onset exogenous feeding Enrichment/Bioencapsulation - 6-8hrs+ Advantages Improve nutrient profile (selective; i.e. HUFA/PUFA, AA, etc.) Disadvantages Larger size, digestibility decreased, faster.

Energetics of Artemia Culture: 

Energetics of Artemia Culture Goal: maximize energy transfer from nauplii to fish Energy content of nauplii depends on yolk reserves Minimize time to hatching Densities, salinity, light, temperature Minimize time in culture post-hatch Feed out as close to hatch as possible (unless enriching)

Artemia for Zebrafish: 

Artemia for Zebrafish Matching Artemia for Life Cycle Larval Juvenile Adult Suggested Overall Strategy Easy (labor limited) Less (but still) easy (labor available)

Larval Zebrafish (6-20 dpf): 

Larval Zebrafish (6-20 dpf) Gape Maximal gape (first feeding) ~100 uM (Patricia Hernandez) Suspension Water column, actively swimming Nutrient Profile High protein, lipids, essential vitamins/minerals; carbohydrates less important Digestibility High Target: early 1st instar nauplii, @ 8dpf (12dpf)

Juvenile Zebrafish (20-60 dpf): 

Juvenile Zebrafish (20-60 dpf) Gape >100 uM, can take nauplii whole Suspension Water column, actively swimming Nutrient Profile High protein, lipids, essential vitamins/minerals; carbohydrates less important Digestibility High Target: early 1st instar, enriched 2nd instar suitable

Adult Zebrafish (60 dpf +): 

Adult Zebrafish (60 dpf +) Gape Can take nauplii, metanauplii (2,3) with ease Suspension Water column, surface, bottom Nutrient Profile Moderately high protein, high lipid, vitamin C, essential minerals/vitamins, carbohydrates less important Digestibility High Target: early first instar or enriched nauplii (HUFA/PUFA, vitamin C)

Suggested Overall Strategy (Easy): 

Suggested Overall Strategy (Easy) Decapsulate in large batches Store pre-aliquotted or in bulk at 4C Hatch out under idealized conditions Harvest, feed out at early 1st instar

Suggested Overall Strategy (A little less easy): 

Suggested Overall Strategy (A little less easy) Decapsulate in large batches Store pre-aliquotted or in bulk at 4C Hatch out under idealized conditions Harvest portion, feed out at early first instar Harvest portion at late 1st/early 2nd instar, enrich with Selco, Algamac, etc., and feed out to broodstock after > 6 hours.

References: 

References Manual on the production and use of live food for aquaculture Lavens, P. (ed.); Sorgeloos, P. (ed.) / Food and Agriculture Organization of the United Nations (FAO) , 1996 http://www.fao.org/DOCREP/003/W3732E/w3732e00.htm#Contents Artemia Production for Marine Larval Fish Culture, Treece, G. 2000, Pub. of Southern Regional Aquaculture Center. http://aquanic.org/publicat/usda_rac/efs/srac/702fs.pdf Enrichment of Artemia For Use in Freshwater Ornamental Fish Production , Tamaru et. al, 1999, Center for Tropical and Subtropical Aquaculture, Publication #133. http://www.ctsa.org/upload/publication/CTSA_133631672859313490600.pdf Use of decapsulated Artemia cysts in ornamental fish culture Lim et al., 2002 Aquaculture Research Vol. 33 Issue 8 Page 575 July 2002

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