Dunaliella, a genus of unicellular, biflagellate green algae, is one of the most studied microalgae for mass culture and is of commercial importance as a source of natural -carotene. Dunaliella species have the desirable properties of halotolerance and photoautotrophy that makes their large-scale culture simple and cheap using resources unsuitable for conventional agriculture. The ease and cost-effectiveness of culture makes Dunaliella a desirable target for increased production of natural compounds by metabolic engineering or for exploitation as biological factories for the synthesis of novel high-value compounds. However, the lack of efficient genetic transformation systems has been a major limitation in the manipulation of these microalgae. In chapter four we describe the development of a nuclear transformation system for Dunaliella tertiolecta. The gene encoding the phleomycin-binding protein from Streptoalloteichus hindustanus, was chosen as the selectable marker as this protein retains activity at high salt concentrations. To drive expression of the chosen selectable marker, two highly expressed Dunaliella tertiolecta RbcS genes and their associated 5' and 3' regulatory regions were isolated and characterised (chapter three). Dunaliella transformation cassettes containing the RbcS promoter and terminator regions flanking the ble antibiotic resistance gene were constructed. These expression cassettes were tested in Chlamydomonas reinhardtii cells and found to drive expression of the ble gene in this heterologous system. This study also demonstrated that truncation of both the D. tertiolecta RbcS1 and RbcS2 regulatory regions significantly increases the expression of the ble gene in C. reinhardtii cells. To determine if the foreign DNA could stably integrate into the Dunaliella genome, four transformation methods: microprojectile bombardment, glass bead-mediated transformation, PEG-mediated transformation and electroporation were tested and a number of parameters varied. Southern blot analysis revealed that the plasmid DNA transiently entered the Dunaliella cells following electroporation but was rapidly degraded. Following electroporation, one stably transformed Dunaliella line was recovered. This is the first demonstration of the stable transformation of this alga. Chloroplast transformation is becoming a favoured method for the production of recombinant proteins in plants, as levels of heterologous protein are often higher than those achieved by transforming the nucleus. The Dunaliella chloroplast genome has not been genetically characterised, and thus there were no existing promoter and terminator sequences or sequences of intergenic regions that could be used for vectors in transformation of the chloroplast. Therefore, this study aimed to isolate and characterise promoters of highly expressed genes and matching terminators capable of driving transgene expression, and also to characterise intergenic regions that would be suitable insertion sites for the vector construct (chapter five). The complete gene sequence of two highly expressed Dunaliella chloroplast genes psbB and rbcL including the promoter and terminator regions as well as the coding sequence of the psbA gene were cloned and sequenced. In addition, the psbA gene is useful as a selectable marker as introduced mutations confer resistance to the herbicide 3-(3,4-Dichlorophenyl)-1,1-Dimethylurea (DCMU). Two homologous transformation constructs based on mutated psbA genes were developed and tested using microprojectile bombardment. A number of parameters were tested including: the size of the gold microprojectile particle, the distance of the plates from the point of discharge, plating onto membranes or filter paper, helium pressure, addition of an osmoticum to the medium and recovery time. Although no chloroplast transformants were recovered in this study, these homologous recombination constructs should prove useful in the development of a chloroplast transformation protocol. The other major component of this study was to investigate the use of microalgae as an expression system for the production of recombinant proteins. Transformation of Chlamydomonas reinhardtii, a species related to Dunaliella, is well developed. In chapter six, this study examined the expression of two human proteins, -lactalbumin and IGF-1 in Chlamydomonas reinhardtii. Plasmids containing the C. reinhardtii RbcS2 promoter upstream of the cDNAs of these two proteins were introduced into C. reinhardtii cells using glass-bead mediated transformation. Transgenic C. reinhardtii lines were generated and shown to contain the transgenes by PCR and Southern hybridisation. RT- PCR and northern hybridisation were subsequently used to demonstrate that the transgenes were transcriptionally active. The transcripts however, could only be detected by RT-PCR indicating that the genes were transcribed at low levels. Accumulation of the -lactalbumin protein could not be demonstrated, suggesting that although the transgenes were transcribed, they were either not translated or translated at levels below the sensitivity of western blot analysis or that any protein produced was rapidly degraded. Previous studies have indicated that in microalgae codon usage is vital in translation of the foreign protein. Codon modification of the IGF-I and -lactalbumin genes should lead to higher levels of protein accumulation. This study reports the first successful stable nuclear transformation of Dunaliella tertiolecta. Therefore it is now feasible that Dunaliella can be examined as a bioreactor for the expression of recombinant proteins. In addition, two chloroplast genes (psbB and rbcL) and their corresponding promoters and terminators have been characterised and a selectable marker cassette based on the mutated psbA gene constructed.

Thesis (M.S.)--Mississippi State University. Department of Biological Sciences. / Bibliography: leaves 30-35. Also available on the World Wide Web.

Thesis (Ph. D.)--Ohio State University, 2007. / Title from first page of PDF file. Includes bibliographical references (p. 145-161).

Thesis (M.Tech.:Biotechnology)-Dept. of Biotechnology, Durban University of Technology, 2007 xvi, 185 leaves / Spirulina is a blue-green, multicellular, filamentous cyanobacterium that can grow to sizes of 0.5 millimetres in length. It is an obligate photoautotroph and has a pH growth range from 8.3 to 11.0.The large-scale production of Spirulina biomass depends on many factors, the most important of which are nutrient availability, temperature and light. These factors can influence the growth of Spirulina and the composition of the biomass produced by changes in metabolism. Brine effluent from cooling towers of electricity generating plants may provide an ideal growth medium for Spirulina based on its growth requirements, i.e. high alkalinity and salinity. The aim of this research was to optimise brine effluent from cooling towers by supplementing it with salts, in order to use this optimised effluent in a small open laboratory raceway pond in an attempt to increase the biomass production of Spirulina.

Made available in DSpace on 2014-06-11T19:32:54Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-10-27Bitstream added on 2014-06-13T20:24:21Z : No. of bitstreams: 1 nunes_m_dr_jabo.pdf: 789915 bytes, checksum: d33780e723c4af1036139660c9582f18 (MD5) Bitstreams deleted on 2016-10-27T11:27:29Z: 000681810.pdf,. Added 1 bitstream(s) on 2016-10-27T11:28:04Z : No. of bitstreams: 1 000681810.pdf: 562297 bytes, checksum: 2a5bb2ece78e1bfaa1bd6aca60814546 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A microalga Haematococcus pluvialis é conhecida como o microrganismo que apresenta maior rendimento final de astaxantina em sua biomassa, quando submetida a fatores de estresse celular eficientes. Contudo ainda apresenta uma característica de crescimento desfavorável quando comparada a outras espécies de microalgas cultivadas em escala comercial, visto que possui uma taxa de crescimento intrínseca, resultando em baixa densidade celular ao final dos cultivos. Assim, o rendimento final do pigmento é relativamente baixo. Neste sentido, este estudo teve por objetivo avaliar a resposta de Haematococcus pluvialis ao processo de indução à carotenogênese por meio de estresse luminoso e nutricional, e promover o aumento de biomassa vegetativa da microalga através da adição da rizobactéria promotora de crescimento em plantas, Azospirillum brasilense V6, estirpe produtora do fito hormônio AIA (ácido indol – acético), em cultivos estanques, visando obter maior rendimento final de astaxantina. O trabalho foi dividido em duas fases. Primeiramente, no cultivo referente ao controle (contendo apenas H. pluvialis) foram aplicadas duas combinações de fatores de estresse celular para indução a síntese de astaxantina pela microalga, visando a escolha do método de estresse a ser aplicado na fase seguinte. As células de H. pluvialis foram submetidas ao estresse por alta intensidade luminosa (350 μmol photons m-2 s-1) ou ao mesmo estresse luminoso aliado a suplementação com CO2 (4%) na aeração fornecida na fase exponencial de crescimento. Avaliou-se, entre outros fatores de resposta celular, a concentração final de astaxantina na biomassa após 10 dias de estresse. As concentrações do pigmento foram 4,15 e 17,66 mg g-1, respectivamente, para as culturas submetidas ao estresse luminoso e para... / The microalgae Haematococcus pluvialis is known as the microorganism that has a highest final yield of astaxanthin in its biomass, when induced by efficient stress factors. However, still presents a characteristic of unfavorable growth when compared to other species of microalgae grown on a commercial scale, once it has an intrinsic growth rate that provides low cell density in the culture. Thus, the final yield of the pigment is relatively low. Thus, this study aimed to evaluate the response of Haematococcus pluvialis submitted to carotenogenesis induction process through light and nutrient stress, and promotion of vegetative microalgae biomass increase through the addition of the growth promoter bacteria in plants, Azospirillum brasilense V6, a strain that produce the phyto hormone IAA (indole - acetic acid). The experiments were performed in “batch” systems, aiming to obtain higher final yield of astaxanthin. The work was divided into two phases. First, to the control (containing only H. pluvialis) it was applied two combinations of stress factors to induce cellular synthesis of astaxanthin by the microalgae, to define the method of stress to be applied in the next phase. The cells of H. pluvialis were submitted to stress by high light intensity (seven times the original) or the same light stress combined with CO2 supplementation (4%) in the aeration provided in the exponential growth phase. We evaluated, among other factors of cellular response, the final concentration of astaxanthin in the biomass after 10 days of stress. The pigment concentrations were 4.15 and 17.66 mg g-1, respectively, for cultures submitted to light stress and to those who received the same light stress add with the increase of C / N ratio in the culture medium. So, for the next experimental phase, the combination... (Complete abstract click electronic access below)

abstract: Second-generation biofuel feedstocks are currently grown in land-based systems that use valuable resources like water, electricity and fertilizer. This study investigates the potential of near-shore marine (ocean) seawater filtration as a source of planktonic biomass for biofuel production. Mixed marine organisms in the size range of 20µm to 500µm were isolated from the University of California, Santa Barbara (UCSB) seawater filtration system during weekly backwash events between the months of April and August, 2011. The quantity of organic material produced was determined by sample combustion and calculation of ash-free dry weights. Qualitative investigation required density gradient separation with the heavy liquid sodium metatungstate followed by direct transesterification and gas chromatography with mass spectrometry (GC-MS) of the fatty acid methyl esters (FAME) produced. A maximum of 0.083g/L of dried organic material was produced in a single backwash event and a study average of 0.036g/L was calculated. This equates to an average weekly value of 7,674.75g of dried organic material produced from the filtration of approximately 24,417,792 liters of seawater. Temporal variations were limited. Organic quantities decreased over the course of the study. Bio-fouling effects from mussel overgrowth inexplicably increased production values when compared to un-fouled seawater supply lines. FAMEs (biodiesel) averaged 0.004% of the dried organic material with 0.36ml of biodiesel produced per week, on average. C16:0 and C22:6n3 fatty acids comprised the majority of the fatty acids in the samples. Saturated fatty acids made up 30.71% to 44.09% and unsaturated forms comprised 55.90% to 66.32% of the total chemical composition. Both quantities and qualities of organics and FAMEs were unrealistic for use as biodiesel but sample size limitations, system design, geographic and temporal factors may have impacted study results. / Dissertation/Thesis / M.S.Tech Technology 2011

La modélisation métabolique est un outil performant pour mieux comprendre, prédire et optimiser les bioprocédés, particulièrement lorsqu'ils impliquent des molécules d'intérêt. Malheureusement, l'utilisation de cette approche de modélisation pour des métabolismes dynamiques est difficile à cause du manque de données expérimentales nécessaires pour définir et calibrer les cinétiques des réactions appartenant aux chemins métaboliques. C'est pourquoi, les modèles métaboliques sont souvent utilisés sous l'hypothèse de croissance équilibrée. Cependant, pour certains procédés comme la croissance photoautotrophique des microalgues, l'hypothèse de croissance équilibrée ne semble pas raisonnable à cause de la synchronisation de leur cycle circadien sur la lumière du jour. Cependant, une compréhension approfondie du métabolisme des microalgues est nécessaire afin d'optimiser les rendements de production des bioprocédés basés sur ces microorganismes, comme par exemple la production de biocarburants.Dans cette thèse, DRUM, une nouvelle approche de modélisation métabolique dynamique qui prend en compte la croissance non-équilibrée, a été développée. La première étape de l'approche consiste à découper le réseau métabolique en sous-réseaux décrivant des réactions qui sont spatialement et fonctionnellement proches et supposés satisfaire une croissance équilibrée. Les métabolites interconnectant les sous-réseaux peuvent alors avoir un comportement dynamique. Puis, grâce à l'analyse de modes élémentaires, chaque sous-réseau est réduit à des réactions macroscopiques, pour lesquelles des cinétiques simples sont supposées. Enfin, un système d'équations ordinaires différentielles est obtenu pour décrire la consommation des substrats, la production de biomasse, les produits excrétés et l'accumulation de certains métabolites intracellulaires.DRUM a été appliquée à l'accumulation des lipides et des carbohydrates de la microalgue Tisochrysis lutea soumise à des cycles jour/nuits en condition d'azote normal et de carence azotée. Le model décrit avec précision les données expérimentales. DRUM a également été appliquée à la microalgue Chlorella Sorokiniana en croissance hétérotrophique, montrant que la croissance équilibrée est valide dans ce cas-là. / Metabolic modeling is a powerful tool to understand, predict and optimize bioprocesses, particularly when they imply intracellular molecules of interest. Unfortunately, the use of metabolic models for time varying metabolic fluxes is hampered by the lack of experimental data required to define and calibrate the kinetic reaction rates of the metabolic pathways. For this reason, metabolic models are often used under the balanced growth hypothesis. However, for some processes such as the photoautotrophic metabolism of microalgae, the balanced-growth assumption appears to be unreasonable because of the synchronization of their circadian cycle on the daily light. Yet, understanding microalgae metabolism is necessary to optimize the production yield of bioprocesses based on this microorganism, as for example production of third-generation biofuels.In this PhD thesis, DRUM, a new dynamic metabolic modeling framework that handles the non-balanced growth condition and hence accumulation of intracellular metabolites was developed. The first stage of the approach consists in splitting the metabolic network into sub-networks describing reactions which are spatially and functionally close, and which are assumed to satisfy balanced growth condition. The left metabolites interconnecting the sub-networks behave dynamically. Then, thanks to Elementary Flux Mode analysis, each sub-network is reduced to macroscopic reactions, for which simple kinetics are assumed. Finally, an Ordinary Differential Equation system is obtained to describe substrate consumption, biomass production, products excretion and accumulation of some internal metabolites.DRUM was applied to the accumulation of lipids and carbohydrates of the microalgae Tisochrysis lutea under day/night cycles in normal and nitrogen starvation conditions. The resulting model describes accurately experimental data. It efficiently predicts the accumulation and consumption of lipids and carbohydrates. DRUM was also applied to the microalgae Chlorella Sorokiniana in dark heterotrophic growth, showing that the balanced-growth assumption was valid in this case.

In marine environments, eukaryotic marine microalgae coexist with the viruses that infect them. Marine microalgae are the main primary producers in the oceans and are at the base of the marine food web. Viruses play important roles in top-down control of algae populations, cycling of organic matter, and as evolutionary drivers of their hosts. Algae must adapt in response to the strong selection pressure that viruses impose for resistance to infection. In addition to biotic selection pressures such as viral infections, algae must also adapt to their abiotic environment. Global climate change is affecting temperature, salinity, pH, light and nutrient concentrations in the oceans, particularly in surface waters, where microalgae live. Currently, little is known about how consistent the effects of viruses on their hosts are, whether the cost of host resistance varies across environments, and whether there is a trade-off between maintaining resistance to viruses and adapting to other environmental changes. The marine picoeukaryote Ostreococcus tauri is abundant in Mediterranean lagoons, where it experiences large fluctuations in environmental conditions and co-occurs with lytic viruses (Ostreococcus tauri viruses – OtVs). Viral infection causes lysis of susceptible (S) cells, however a small proportion of cells are resistant (R) and avoid lysis. Some resistant O. tauri populations can coexist with infectious viruses, and it has been proposed that these viruses are produced by a minority of susceptible cells within a mainly resistant population. These populations are referred to as resistant producers (RP). Virus production in RP populations is unstable and eventually they shift to R populations. I used O. tauri and one of its viruses, OtV5, as a model system to investigate whether cells that are susceptible or resistant to virus infection adapt to environmental change differently and whether there is a cost of being resistant. For the first time, I evolved susceptible and resistant hosts of a marine alga separately under a range of environments and directly compared their plastic and evolved responses. I showed that resistant populations of O. tauri maintained their resistance for more than 200 generations in the absence of viruses across all environments, indicating that the resistance mechanism is difficult to reverse. Furthermore, I did not detect a cost of being resistant, as measured by population growth rate and competitive ability. Virus production in RP populations stopped in all environments and all populations became R. In addition, I found that virus production in RP O. tauri populations can fluctuate before completely ceasing, and that phosphate affected the length of time it took for virus production to stop. These results, combined with mathematical modelling of O. tauri infection dynamics, provide support for the prediction that RP populations consist of a mixed population of susceptible and resistant cells. By examining multiple environments and resistance types, we can better understand first, how microalgae populations adapt to environmental change and second, the ecological and evolutionary consequences of maintaining resistance to viruses in common marine picoeukaryotes.

Microalgas são micro-organismos fotossintetizantes que convertem CO2 majoritariamente em lipídios, proteínas e carboidratos. A produção de microalgas é indicada atualmente como alternativa para biomitigação de CO2 e para geração de biocombustíveis, a partir da conversão da biomassa através de processos químicos e biotecnológicos. As vantagens das microalgas estão na sua maior velocidade de crescimento em relação a vegetais oleaginosos superiores e em seu teor lipídico, que para algumas espécies pode chegar a valores maiores que 50%. Apesar do potencial envolvendo as microalgas, muitos desafios ainda precisam ser superados para tornar viável a aplicação desses micro-organismos para fins energéticos. São necessários desenvolvimentos nas mais diversas áreas, abordando os seguintes aspectos: seleção e melhoramento genético de espécies, alcance de maior eficiência fotossintética, desenvolvimento de sistemas de produção e de seu escalonamento, desenvolvimento de sistemas e processos de colheita, extração e processamento, aproveitamento de nutrientes provenientes de resíduos, otimização de condições operacionais, dentre outros. Este trabalho teve por objetivo determinar as melhores condições de crescimento da microalga marinha Nannochloropsis oculata em um fotobiorreator airlift. Os experimentos foram realizados seguindo um delineamento composto central rotacional com temperatura, (19 a 29 °C), concentração de nitrato no meio de cultivo (f/2) (25 a 125 mg.l-1) e intensidade luminosa (3636 a 10364 lux) como variáveis de estudo. Uma planta laboratorial com 12 fotobiorreatores foi construída, permitindo realizar os experimentos do referido planejamento em dois blocos. As variáveis de resposta estudadas e os respectivos melhores resultados experimentais obtidos foram de 482,7 mg.l-1 para a máxima concentração de biomassa, nas condições de 21 °C, 105 mg.l-1 de NaNO3 e 9000 lux, taxa instantânea de crescimento no período exponencial de 0,5624 d-1, nas condições de 24 °C, 75 mg.l-1 de NaNO3 e 7000 lux e percentual de lipídios em biomassa liofilizada de 30,36%, nas condições de 21 °C, 45 mg.l-1 de NaNO3 e 5000 lux. / Microalgae are photosynthetic microorganisms that convert CO2 mainly into lipids, proteins and carbohydrates. Microalgae production is currently pointed out as an alternative for CO2 biomitigation and generation of renewable biofuels, from biomass conversion by chemical and biotechnological processes. Microalgae advantages are fastest growth comparing with oil crops and their higher lipid content, which for some species can reach values above 50%. Despite the potential involving microalgae, many challenges remain to be overcome to make feasible the application of these microorganisms for energy purposes. We need to develop several areas, addressing the following issues: selection and genetic improvement of species, reaching higher photosynthetic efficiency, development of production systems and their scale up, development of systems and procedures for harvest, extraction and processing, use of nutrients from flue gases and wastewater, optimization of operating conditions, etc. This study aimed to determine the best conditions for growth of the marine microalgae Nannochloropsis oculata in airlift phootobioreactor. Experiments were carried out following a central composite design of the following variables: temperature (19 to 29 ° C), nitrate concentration in the culture medium (f/2) (25 to 125 mg.l-1) and irradiance (3636 to 10364 lux). A laboratory plant was built with 12 photobioreactors, allowing perform the central composite design in two blocks. The response variables studied and the best experimental results obtained were 482,7 mg.l-1 for maximum biomass concentration under conditions of 21 °C, NaNO3 concentration 105 mg.l-1 and 9000 lux, instantaneous rate of increase in exponential period equal to 0.5624 d-1 under the conditions of 24 °C, NaNO3 concentration 75 mg.l-1 and 7000 lux and percentual lipid content in lyophilized biomass of 30.36% under the conditions of 21 °C, NaNO3 concentration 45 mg.l-1 and 5000 lux.

SILVA NETO, José Fernandes da. Farinha de Spirulina como aditivo atrato-palatabilizante em dietas balanceadas para o camarão marinho Litopenaeus vannamei. 2010. 44 f. : Dissertação (mestrado) - Universidade Federal do Ceará, Centro de Ciências Agrárias, Departamento de Engenharia de Pesca, Fortaleza-CE, 2010 / Submitted by Nádja Goes (nmoraissoares@gmail.com) on 2016-07-18T12:43:34Z No. of bitstreams: 1 2010_dis_jfsilvaneto.pdf: 604995 bytes, checksum: db4e480a37925c8c84d3801a616871b4 (MD5) / Approved for entry into archive by Nádja Goes (nmoraissoares@gmail.com) on 2016-07-18T12:43:54Z (GMT) No. of bitstreams: 1 2010_dis_jfsilvaneto.pdf: 604995 bytes, checksum: db4e480a37925c8c84d3801a616871b4 (MD5) / Made available in DSpace on 2016-07-18T12:43:54Z (GMT). No. of bitstreams: 1 2010_dis_jfsilvaneto.pdf: 604995 bytes, checksum: db4e480a37925c8c84d3801a616871b4 (MD5) Previous issue date: 2010 / At present, there is a great effort to partially or completely replace fishmeal in artificial diets for less costly and more predictable vegetable protein ingredients. Experimental results of some studies indicate the potential of the Spirulina meal as a growth impeller in diets for marine shrimp. Despite its nutritional quality, no work has been conducted so far about the use of Spirulina meal as an additive in complete diets for Litopenaeus vannamei. The present work aimed at investigating the growth performance and feeding preference of L. vannamei raised under controlled laboratory conditions fed diets supplemented or deprived with Spirulina meal. Juveniles of L. vannamei (3.89  0.25 g) were stocked under intensive conditions at 44 shrimp/tank (64 juveniles/m²) in 28 polyethylene tanks of 500 L and raised for 71 days. Diets were supplemented with 0.5% of a commercial feed attractant for marine shrimp (MAC and BAC) or with 0.5% of Spirulina meal (MSP and BSP). In MAC and MSP and BAC and BSP, inclusion of fishmeal was reduced at 25% and 50%, respectively. In a second study, diets were offered to animals in a two feeding trays clearly identified, in equal amounts, delivered at the same time in the opposite sides of each tank and simultaneously recovered. Feed remaining in each feeding tray was collected and weighted to calculate the dry weight. Weekly shrimp weight gain fed diet MSP (0.89 ± 0.03 g) was not significantly different from those fed diet MAC (0.89 ± 0.01 g). Feed conversion rate and protein efficiency rate for shrimp fed diet MSP were not significantly different from those seen for CN1 and P. Final body weight and survival of shrimp fed diet MSP were not significantly different from those observed for CN1 and P. The attractability study demonstrated that MSP showed a significantly higher preference compared to MAC diet. It can be concluded that Spirulina meal added at 0.5% in a complete diet for juveniles of L. vannamei acted as a feeding attractant capable of promoting the same effects of a commercial additive. Further work is required to evaluate others inclusion levels, cheap production techniques, compounds responsible for attractability’s Spirulina meal etc / Há, presentemente, grande esforço de pesquisa no sentido de se substituir, parcial ou totalmente, a farinha de peixe das dietas artificiais por fontes protéicas vegetais, de menor custo e maior previsibilidade de produção. Os resultados experimentais obtidos em alguns trabalhos evidenciam o bom potencial da farinha de Spirulina como aditivo impulsor do crescimento em dietas para camarões marinhos. Apesar de sua qualidade nutricional, nenhum trabalho foi conduzido até agora sobre o uso da farinha de Spirulina como aditivo em dietas completas para L. vannamei. O presente trabalho objetivou o estudo do desempenho zootécnico e da preferência alimentar de juvenis de Litopenaeus vannamei criados em laboratório sob condições controladas alimentados com diferentes dietas suplementadas ou não com farinha de Spirulina. Juvenis de L. vannamei (3,89 ± 0,25 g) foram estocados intensivamente em 28 tanques circulares de polietileno de 500 L, na densidade de 44 camarões/tanque (64 juvenis/m2) por 71 dias. As dietas foram suplementadas com 0,5% de um atrativo comercial para rações de camarão (MAC e BAC) ou com 0,5% de farinha de Spirulina (MSP e BSP). Em MAC e MSP e em BAC e BSP houve reduções de 25% e 50% do nível de inclusão de farinha de peixe, respectivamente. No segundo experimento, as dietas foram oferecidas aos animais em duas bandejas claramente identificadas, em quantidades iguais, colocadas no mesmo momento, em lados opostos dentro de cada tanque e foram recolhidas no mesmo instante. A ração remanescente em cada bandeja de alimentação foi coletada e pesada para calcular o peso seco posteriormente. O ganho em peso semanal dos camarões alimentados com a ração MSP (0,89 ± 0,03 g) não foi significativamente diferente daqueles que se alimentaram com a dieta MAC (0,89 ± 0,01 g) e P (0,95 ± 0,08 g). O fator de conversão alimentar e a taxa de eficiência protéica dos camarões alimentados com MSP não foram estatisticamente diferentes daqueles observados em CN1 e P. O peso corporal final e a sobrevivência dos camarões alimentados com MSP não foram significativamente diferentes daqueles observados em CN1 e P. O estudo da atratividade mostrou que MSP teve preferência significativamente maior pelos camarões do que a dieta MAC. Pode ser concluído que a farinha de Spirulina adicionada a 0,5% em uma dieta completa para juvenis de L. vannamei atuou como um atrativo alimentar, e foi capaz de promover os mesmos efeitos de um aditivo comercial. Trabalhos futuros são requeridos para avaliar outros níveis de inclusão, técnicas de produção baratas, compostos responsáveis pela atratividade da farinha de Spirulina etc