DIATOMS AS FEED FOR AQUACULTURE By John J. Perez C.
Centric diatom Pseudo-nitzschiaThalassiosira Pennate diatom siliceous hoops (girdle bands)Pores are species specific Greek diatomos, ‘cut in half ’ chlorophyll a, fluorescing red when illuminated with blue Light
Unique combination of genes and metabolic pathways distinguish diatoms Thalassiosira Two of the novel type of spores of Chaetoceros furcillatus nordenskioeldii Enormous amounts of Thalassiosira taelataYoung auxospore of Pseudo-nitzschia multiseries diversity encapsulated within diatoms http://www.aquatic.uoguelph.ca/Human/Research/ijkl/kaczmarskai.htm
Life in the ocean waves Eukaryoticphytoplankton Cyanobacteria Heterotrophic Archaea bacteria viruses Protists
Benthic diatoms are the main food source for abalone post-larvae
monospecific cultures of benthic diatoms have successfully been employed as feed for the culture of abalone post-larvae
in Taiwan, abalone post-larvae grown in hatcheries are usually fed with naturalpopulations of benthic diatoms, following the traditional method of using biofilms of mixed benthic diatoms as the settlement substrata for abalone post-larvae in hatcheriesa photosynthetically active biofilm of diatoms, e.g. Gyrosigma spp Biofilm of mixed centric diatoms
postlarvae of various abalone species have a better growth rate when fed with cultured diatoms than those fed with natural unknown species of diatoms Post Larval spat: After 2-3 weeks swimming around in the water column, the pelagic veliger larva loses its velium and metamorphoses into the post-larval stage (spat). It loses its positive phototaxis (movement towards the sunlight), moves down from the water surface, and settles on hard surfaces in intertidal and subtidal areas. Settlement is triggered by a chemical that is produced by Coralline algae and adult abalone. Abalone feed on Coralline algae and the presence of adults indicates a good habitat to live! The post-larva sheds its swimming hairs (cilia) and begins to develop the adult shell form. This is the first feeding stage where they start to feed on diatoms.
Carbajal-Miranda et al. (2005) Navicula incertaAmphiprorapaludosa Haliotis rufescens
Daume et al. (2000) Cylindrotheca closterium Haliotis rubra Amphora sp.Navicula sp., N. jeffr Cocconeis sp
Gordon et al. (2006)Haliotis discusAmphora luciae Navicula cf. lenzii
Haliotis irisAchnanthes longipes Kawamura et al. (1998)Nitzschia ovalis Nitzschia spCocconeis p. Navicula britannica
Gallardo and Buen (2003) Mixed diatoms vs.monospecific cultures of Navicula Haliotis asinina
little information concerning diatoms as feed for Haliotis diversicolor
Kawamura et al., 1998 Poor and unpredictable performance of abalone postlarvaedifferences in lipid,the species of protein anddiatoms they extracellularhave been fed polymeric substances (EPSs)
Hypothetical cellular pathways and processes in iron-limited pennate diatom cells. All roman green or red type depictsgene transcripts found to be up- or down-regulated, respectively. Italicized and underlined green type indicatesmetabolites found to be enriched relative to total protein in iron-limited cells. DF, diffusion factor; EPS, extracellularpolymeric substances; FR, ferric reductase; HMA, heavy metal-associated; PCD, programmed cell death; ROS, reactiveoxygen species.
AIMS• to improve the growth and the survival of abalone post-larval stages in a specific growth system using specific diatoms species• a better understanding of their basic dietary requirements farmers attempting to produce mollusks and crustaceans from the larval stage• high cost of producing live food (microalgae)• up to 30% of the total cost of production (Valenzuela-Espinoza et al., 1999).
Alternative• use immobilized microalgae• can be cheaper than algae produced by traditional methods• ready for use (Chen, 2003).
Specific aims• Survey the diversity of diatoms species found in H. diversicolor hatcheries.• Isolate and develop a monoculture that could be immobilized and encapsulated in alginate beads for long-term storage as algal stock.
monospecific algal stocks used as feed forcultivating the post-larvae of H. diversicolor• Lipids• Proteins• EPS – soluble EPS – bound EPS – internal carbohydrate – residual carbohydrate
Collection and preparatory cultures of benthic diatoms Diatoms from small abalone hatchery ponds scraped from abalone post-larvae settlement substrates (plastic plates) collected in l L collection bottles Yean-Chang Chen, Ph.D. Associate Professor, placed in a cool icebox Department of Aquaculture, National Taiwan Ocean University,transported to the Algal Laboratory Keelung, Taiwan Email: firstname.lastname@example.org. of the National Taiwan Ocean tw email@example.com University, Keelung, Taiwan Tel: 886 2 24622192 ext. 5221
Martek 120-liter Deep aerated tank used for the culture of Nannochloropsis forphotobioreactor aquaculture
Eicosapentaenoic acid 20:5(n-3)(EPA, 5,8,11,14,17-cis-eicosapentaenoic acid) EPA is an omega-3 fatty acid• an n-3 C20-polyunsaturated fatty acid that is metabolically active. with a doublefrom the endstartingcarbonthe third carbon atom bond (C=C) of the after chain.a carboxylic acid with a 20-carbon chain and five cis double bondsthe first double bond is located at the third carbon from the omega end.
EPA and its derivatives have proved beneficial in prevention and treatment of certain medical conditions • coronary heart disease • blood platelet EPA is effective aggregation also in arresting and minimizing • abnormal cholesterol tumor growth levels • several carcinomas
EPA is currently sourced from fish oil • No other sources are commercially available. – fluctuates in price and quality. – contamination of fish oil with pesticides and heavy metals. – an alternative economic and consistent source of EPA is needed. – Microalgae are one potential source.
Annual EPA demanddemand is expected to increase dwindling supplies of fish oil 125 tones in Japan Current market price of EPA ethyl ester (95% pure) about $650/kg