Advanced

The Cyanophyte Arthrospira Fusiformis in African Waters - Eco-Physiology and Potential Use in Tropical Aquaculture

Mussagy, Aidate LU (2006)
Abstract (Swedish)
Popular Abstract in Swedish

Blågröna alger (cyanobakterier) av släktet Arthrospira förekommer i salthaltiga, alkaliska, tropiska vatten i Afrika, Asien och Centralamerika. Kanembu stammen vid Chadsjön och aztekerna i Mexiko har av tradition använt Arthrospira i matlagningen som ett näringskomplement. Under senare år har släktet Arthrospira uppmärksammats vetenskapligt och kommersiellt. Nu odlas Arthrospira i stor skala över hela världen och saluförs som hälsokost under namnet Spirulina. Målet för denna undersökning var att öka kunskapen om släktets taxonomi, fysiologi och toxikologi genom undersökning av Arthrospira stammar insamlade och renodlade i Moçambique. Näringsvärdet av Arthrospira undersöktes även i... (More)
Popular Abstract in Swedish

Blågröna alger (cyanobakterier) av släktet Arthrospira förekommer i salthaltiga, alkaliska, tropiska vatten i Afrika, Asien och Centralamerika. Kanembu stammen vid Chadsjön och aztekerna i Mexiko har av tradition använt Arthrospira i matlagningen som ett näringskomplement. Under senare år har släktet Arthrospira uppmärksammats vetenskapligt och kommersiellt. Nu odlas Arthrospira i stor skala över hela världen och saluförs som hälsokost under namnet Spirulina. Målet för denna undersökning var att öka kunskapen om släktets taxonomi, fysiologi och toxikologi genom undersökning av Arthrospira stammar insamlade och renodlade i Moçambique. Näringsvärdet av Arthrospira undersöktes även i laboratorieexperiment.



Analys av fenotyper av Arthrospira arter visade att två av dem kunde klassificeras som A. maxima och A. fusiformis. Molekylär karakterisering baserad på sekvenser från Internally Transcribed Spacer (ITS) mellan generna 16S och 23S rRNA , visade emellertid, att de två arterna, den ena med en tät spiralformad tråd, den andra med en gles spiralformad tråd, liksom också varianten med en rak tråd (som uppstod från de ovan-nämnda arterna) tillhör ITS kluster typ 1.A. Den delsekvens som undersöktes, var identisk i alla tre stammarna. Samma kluster har tidigare rapporterats för stammar isolerade från andra afrikanska lokaliteter.



I undersökningen hur isolerade Arthrospira stammar anpassade sig till havsvattensmiljöer, fann jag att dessa stammar visade god tillväxt, även om den skedde långsammare än i standard Zarrouk medium. Jag upptäckte också att prolin koncentrationen ökade i kulturer odlade i vatten med hög salthalt. Det antyder att prolin möjligen kan fungera som en organisk osmolyt när Arthrospira exponeras för höga salthaltiga miljöer.



Arthrospira stammarna producerade varken microcystiner eller anatoxin-a under de givna experimentella betingelserna. Vidare saknades genen mcyE, som är en del av operonet som kodar för microcystin syntetas, ett resultat som överensstämde med ELISA och HPLC undersökningar. Jag fann emellertid hos samma stammar höga halter av lipopolysaccharid endotoxiner (LPS). Slutligen fann jag, i försök där Arthrospira användes som föda för larverna till den marina hoppkräftan Artemia, en högre dödlighet än i försök där andra mikroalger, som Isochrysis galbana och Tetraselmis suecica användes. Trots att Artemia larvernas överlevnad var lägre när Arthrospira utgjorde dess näring, observerades en högre tillväxt och en snabbare utveckling bland de överlevande larverna än när de fordrades med andra mikroalger. Eventuellt hade Arthrospira en gynnsam effekt på Artemia med avseende på sitt näringsvärde, medan andra faktorer, såsom resistens mot näringsspjälkning och förekomst av LPS kan vara orsaken till den högre dödligheten.



Dessa observationer antyder på möjligheter att odla Arthrospira i havsvatten i länder, såsom Moçambique, vars kust är lång och har stor potential för utveckling av vattenbruk. (Less)
Abstract
The cyanoprokaryote (blue-green algae) genus Arthrospira occurs in saline, alkaline tropical waters of Africa, Asia, and Central America. Traditionally Arthrospira has been used as a food supplement by the Kanembu tribe of Lake Chad and Aztecs living in the valley of Mexico City. It is presently cultivated in large scale throughout the world and sold as a health food supplement due to its nutritional value and potential therapeutic effects. During the past years, the genus Arthrospira has received considerable scientific and commercial attention. The purpose of the present study was to improve our understanding of the taxonomy, as well of relevant physiological and toxicological aspects of this genus by investigating Arthrospira isolated... (More)
The cyanoprokaryote (blue-green algae) genus Arthrospira occurs in saline, alkaline tropical waters of Africa, Asia, and Central America. Traditionally Arthrospira has been used as a food supplement by the Kanembu tribe of Lake Chad and Aztecs living in the valley of Mexico City. It is presently cultivated in large scale throughout the world and sold as a health food supplement due to its nutritional value and potential therapeutic effects. During the past years, the genus Arthrospira has received considerable scientific and commercial attention. The purpose of the present study was to improve our understanding of the taxonomy, as well of relevant physiological and toxicological aspects of this genus by investigating Arthrospira isolated from waters from Mozambique. Further, the nutritional value of Arthrospira was also investigated, with the objective of including it as a food supplement in aquaculture. These studies were based on laboratory experiments and on in vivo bioassays. The phenotypic analysis of the isolated Arthrospira strains revealed that the two strains could be classified as A. maxima and A. fusiformis. However, molecular characterization using the sequences of the Internally Transcribed Spacer (ITS) between the 16S and 23S rRNA genes revealed that the two strains, one with a tightly coiled and the other a loosely coiled trichome and also the variant with a straight trichome (that arose from the two former strains) belonged to the ITS-cluster type I.A and were identical for the partial sequence determined. The same cluster was previously reported for Arthrospira strains isolated from other African locations. In experiments to test the adaptation of the isolated Arthrospira strains to seawater I found that the strains grow well, although at lower a rate, than in standard Zarrouk medium. I also found that proline concentration increased in cultures with high salinity, which is an indication that proline might act as an organic osmolyte whenArthrospira is exposed to high salinity. The Arthrospira strains used in the present study revealed that they produced neither microcystins nor anatoxin-a under the experimental conditions of this study. Also the mcyE gene, part of the operon encoding microcystin synthetase, was not detected, which agrees with results obtained by ELISA and HPLC. However, in the same strains I found high levels of lipopolysaccharide endotoxins (LPS). Finally, when testing Arthrospira as feed for Artemia I found that mortality of Artemia was higher on a diet of Arthrospira than on other microalgal diets, namely Isochrysis galbana and Tetraselmis suecica used as reference diets. Interestingly, although Artemia survival was lower on the Arthrospira diet, equivalent growth and faster ontogenetic development were observed for the surviving Artemia larvae as on the other microalgal diets. Possibly Arthrospira might have a positive effect on Artemia with respect to its nutritional value but some other factors such as digestion resistance and the presence of LPS might have caused the high mortality observed. These findings open an avenue for cultivation of Arthrospira in seawater in countries such as Mozambique with a long coast and great potential for aquaculture development. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Prof. Pettersson, Kurt, University of Uppsala
organization
publishing date
type
Thesis
publication status
published
subject
keywords
limnology, Marinbiologi, marine biology, aquatic ecology, lipopolysaccharide endotoxins (LPS), salinity, osmoregulation, proline, aquaculture feeds, Artemia., Hydrobiology, anatoxin, microcystin, ITS sequences, phenotype analysis, taxonomy, Cyanophyceae, Arthrospira fusiformis, limnologi, akvatisk ekologi
pages
118 pages
publisher
Limnology, Department of Ecology, Lund University
defense location
Blå hallen, Ecology Buliding, Sölvegatan 37, Lund
defense date
2006-12-08 09:30
external identifiers
  • Other:ISRN: SE-LUNBDS/NBLI-06/1061-118 PP
ISBN
91-7105-247-X
language
English
LU publication?
yes
id
284b61d7-336b-4988-9fa2-cab33b4dec67 (old id 547594)
date added to LUP
2007-09-06 09:41:07
date last changed
2016-09-19 08:45:13
@misc{284b61d7-336b-4988-9fa2-cab33b4dec67,
  abstract     = {The cyanoprokaryote (blue-green algae) genus Arthrospira occurs in saline, alkaline tropical waters of Africa, Asia, and Central America. Traditionally Arthrospira has been used as a food supplement by the Kanembu tribe of Lake Chad and Aztecs living in the valley of Mexico City. It is presently cultivated in large scale throughout the world and sold as a health food supplement due to its nutritional value and potential therapeutic effects. During the past years, the genus Arthrospira has received considerable scientific and commercial attention. The purpose of the present study was to improve our understanding of the taxonomy, as well of relevant physiological and toxicological aspects of this genus by investigating Arthrospira isolated from waters from Mozambique. Further, the nutritional value of Arthrospira was also investigated, with the objective of including it as a food supplement in aquaculture. These studies were based on laboratory experiments and on in vivo bioassays. The phenotypic analysis of the isolated Arthrospira strains revealed that the two strains could be classified as A. maxima and A. fusiformis. However, molecular characterization using the sequences of the Internally Transcribed Spacer (ITS) between the 16S and 23S rRNA genes revealed that the two strains, one with a tightly coiled and the other a loosely coiled trichome and also the variant with a straight trichome (that arose from the two former strains) belonged to the ITS-cluster type I.A and were identical for the partial sequence determined. The same cluster was previously reported for Arthrospira strains isolated from other African locations. In experiments to test the adaptation of the isolated Arthrospira strains to seawater I found that the strains grow well, although at lower a rate, than in standard Zarrouk medium. I also found that proline concentration increased in cultures with high salinity, which is an indication that proline might act as an organic osmolyte whenArthrospira is exposed to high salinity. The Arthrospira strains used in the present study revealed that they produced neither microcystins nor anatoxin-a under the experimental conditions of this study. Also the mcyE gene, part of the operon encoding microcystin synthetase, was not detected, which agrees with results obtained by ELISA and HPLC. However, in the same strains I found high levels of lipopolysaccharide endotoxins (LPS). Finally, when testing Arthrospira as feed for Artemia I found that mortality of Artemia was higher on a diet of Arthrospira than on other microalgal diets, namely Isochrysis galbana and Tetraselmis suecica used as reference diets. Interestingly, although Artemia survival was lower on the Arthrospira diet, equivalent growth and faster ontogenetic development were observed for the surviving Artemia larvae as on the other microalgal diets. Possibly Arthrospira might have a positive effect on Artemia with respect to its nutritional value but some other factors such as digestion resistance and the presence of LPS might have caused the high mortality observed. These findings open an avenue for cultivation of Arthrospira in seawater in countries such as Mozambique with a long coast and great potential for aquaculture development.},
  author       = {Mussagy, Aidate},
  isbn         = {91-7105-247-X},
  keyword      = {limnology,Marinbiologi,marine biology,aquatic ecology,lipopolysaccharide endotoxins (LPS),salinity,osmoregulation,proline,aquaculture feeds,Artemia.,Hydrobiology,anatoxin,microcystin,ITS sequences,phenotype analysis,taxonomy,Cyanophyceae,Arthrospira fusiformis,limnologi,akvatisk ekologi},
  language     = {eng},
  pages        = {118},
  publisher    = {ARRAY(0x9253e30)},
  title        = {The Cyanophyte Arthrospira Fusiformis in African Waters - Eco-Physiology and Potential Use in Tropical Aquaculture},
  year         = {2006},
}