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This study aimed to evaluate the integrated culture of the Pacific white shrimp (Litopenaeus vannamei) and the West Indian pointed venus (Anomalocardia flexuosa) reared in a biofloc system. The performance of both species and the phytoplankton community were evaluated. Shrimp monoculture and three stocking densities of West Indian pointed venus (2.5, 5.0 and 7.5 Kg m-3) were evaluated in 0.05 m3 tanks. First of all, the addition of A. brasiliana did not affect the water quality parameters of the culture. Regarding the phytoplankton community, 13 taxa were found: 5 cyanobacteria, 4 dinoflagellates, 3 diatoms and 1 green algae. Although diatoms were dominant at the beginning of cultivation, in the middle and at the end a cyanobacterial dominance was observed (proven by ANOSIM and nMDS). The taxa that most contributed to the abundance of cyanobacteria were Aphanocapsa sp. and Pseudanabaena sp. Regarding the performance of the shrimp, all integrated treatments present the higher growth performances (final weight, yield and survival) when compared to shrimp monoculture. Moreover, gradual mortalities of A. brasiliana were observed, probably due to the high concentration of cyanobacteria. Thus, it can be observed that the integration of molluscs in shrimp culture can reduce the concentration of harmful algae and improve the zootechnical performance of the shrimp.

Astaxanthin is a xanthophyll carotenoid widely used in aquaculture and nutraceutical industries. Among natural sources, the microalga Haematococcus pluvialis is the non-genetically modified organism with the greatest capacity to accumulate astaxanthin. Therefore, it is important to understand emerging strategies in upstream and downstream processing of astaxanthin from this microalga. This review covers all aspects regarding the production and the market of natural astaxanthin from H. pluvialis. Astaxanthin biosynthesis, metabolic pathways, and nutritional metabolisms from the green vegetative motile to red hematocyst stage were reviewed in detail. Also, traditional and emerging techniques on biomass harvesting and astaxanthin recovery were presented and evaluated. Moreover, the global market of astaxanthin was discussed, and guidelines for sustainability increasing of the production chain of astaxanthin from H. pluvialis were highlighted, based on biorefinery models. This review can serve as a baseline on the current knowledge of H. pluvialis and encourage new researchers to enter this field of research.

Haematococcus pluvialis is known as the richest natural source of carotenoid astaxanthin, whose synthesis is related to changes in cells according its complex life cycle and the availability of nutrients present in the culture media. This study’s objective was to evaluate the influence of different culture media under photoautotrophic and mixotrophic conditions on the growth, life cycle, biochemical composition, and astaxanthin production in H. pluvialis. Cultures were performed using the following media: KM1, MM2, Provasoli, modified Provasoli, and how to control the BBM, all kept at 24 ± 1 °C, with constant aeration, light/dark photoperiod 24:0 and irradiance of 60 μmol photons/m2/s. Growth and life cycle were evaluated by daily cell counts under an optical microscope; values of maximum cell density (MCD) and dry biomass were also assessed. Biochemical analyses were chlorophyll (a and b), astaxanthin, total proteins, and fatty acids. Cultivation under photoautotrophic conditions in BBM medium showed higher concentration of chlorophylls a (33 ± 4.0 μg/mL) and b (18 ± 1.6 μg/mL) and protein (62.7 ± 3.38%). Cultivation in modified Provasoli medium, under mixotrophic conditions, showed higher MCD (84.5 ± 11.7), biomass production (4.9 ± 0.0004 mg/mL), fatty acid methyl esters, and astaxanthin productivity (9.28 ± 0.4 mg/L/day). These results demonstrate that the culture media and the culture conditions to which H. pluvialis is submitted stimulate specific metabolic and biosynthetic pathways of the cells, which directly affect the biochemical composition of the microalgae. Modified Provasoli medium proved to be the most efficient in increasing astaxanthin productivity for this species, as it has shown better growth parameters and biomass production.

This study designed a promising integrated model for production of fatty acids and aquaculture inputs using the microalgal biomass of Choricystis minor var. minor. Cultures under photoautotrophic, heterotrophic, and mixotrophic nutritional modes were conducted in fed-batch and the lipids from the different biomasses were extracted and quantified. Then, the biomasses without lipids were used to feed the microcrustacean Daphnia similis. The results indicated the mixotrophic nutritional mode as the most suitable for the production of biomass (8.27 ± 0.70 g L−1) and lipids (32.02 ± 0.11%). In contrast, biomass from the heterotrophic nutritional mode was the most promising for feeding D. similis after lipid extraction (2370 ± 372 Daphnia L−1). The integrated chain developed for biodiesel and aquatic feed is a promising alternative to produce energy with ultra-low environmental impact.

Astaxanthin is a xanthophyll carotenoid widely used in aquaculture and nutraceutical industries. Among natural sources, the microalga

This research evaluated the growth of Daphnia similis in wastewater from Nile tilapia (Oreochromis niloticus) farmed in a biofloc system (carbohydrate:nitrogen of 12:1). During 30 days, physical-chemical and growth variables were measured in the following treatments: DCWC—D. similis growth in clear water with the addition of C. vulgaris (autotrophic culture); DB—D. similis growth in biofloc wastewater from Nile tilapia farmed without the addition of C. vulgaris (mixotrophic culture); and DBC—D. similis growth in biofloc wastewater from Nile tilapia farmed with the addition of C. vulgaris (mixotrophic culture). The biofloc wastewater (DB and DBC) underwent significant changes in water quality (P 0.05) from DB in relation to MAD in the second cycle. Thus, wastewater from Nile tilapia cultivation in a biofloc system as a culture medium for raising D. similis, with the addition of C. vulgaris, proved to be a promising option for producing live food for aquaculture.

Knowledge about phytoplankton communities is important for aquaculture due to their influence on environmental variables. The goal of the study was to evaluate the ecological effect of seaweed Grac...

The purpose of this study was to produce Daphnia magna in wastewater from Tilapia farmed in a biofloc system, to evaluate three different carbohydrate:nitrogen ratios. The experiment was conducted for 30 days following a completely randomized experimental design, with the three treatments: C:N 10:1, C:N 15:1 and C:N 20:1, all fed with Chlorella vulgaris. The physical-chemical variables of the water analyzed were: temperature, dissolved oxygen (DO), pH, TAN, NO2 , hardness and alkalinity. The following growth variables of the Daphnia were also evaluated: Maximum average density (MAD), Maximum density day (MDD), Specific growth rate (SGR), Doubling time (DT) and yield (Y). The water quality variables remained in the range of ideal conditions for the species, presenting significant differences (p

The objective of this study was to evaluate the effect of the addition of Navicula sp. on the growth and fatty acids profile of Litopenaeus vannamei postlarvae in a biofloc system (BFT). Four treatments were used: BFT; BFT 2.5N (addition of 2.5 × 10⁴ cells/ml of Navicula sp.); BFT 5N (addition of 5 × 10⁴ cells/ml of Navicula sp.) and BFT 10N (addition of 10 × 10⁴ cells/ml of Navicula sp.), all in triplicate. The shrimp (1 ± 0.01 mg) were stocked at a density of 3,000 postlarvae/m³ and fed with commercial feed. The diatom was added every 10 days, and at the end of 42 days, shrimp performance, water quality and proximal composition were evaluated. The BFT 5N and BFT 10N treatments had higher performance values, highlighting the values of productivity (2.30 and 2.42 kg/m³) and specific growth rate (15.92 and 16.08%/day), which were higher than the other treatments. In addition, the highest levels of fatty acids were observed in treatments with diatom (BFT 5N and BFT 10N), indicating the benefits of Navicula sp. on growth enhancement and fatty acid content of L. vannamei postlarvae grown in biofloc systems.

Oil spill events in the marine environment can have a deleterious impact on the affected ecosystems, such as coral reefs, with direct consequences for their socioeconomic value. The mutualistic relationship between tropical corals and their dinoflagellate symbionts (Symbiodiniaceae) provide structural and nutritional basis for a high local biodiversity in oligotrophic waters. Here, we investigated effects of crude oil water-accommodated fraction on the competitive fitness of the model zooxanthellae species Symbiodinium glynnii. Results of laboratory essays demonstrate that crude oil carbon is incorporated into the cellular biomass with a concomitant change of δ13C isotopic value. Carcinogenic/mutagenic polycyclic aromatic hydrocarbons were identified in the culture media and were responsible for a linear reduction in population growth of S. glynnii, presumably related to energy relocation for DNA repair. Additionally, the experiments revealed that physiological effects induced by crude oil compounds are genetically inherited by the following generations under non-contaminated growth conditions, and induce a reduction in the competitive fitness to cope with other environmental parameters, such as low salinity. We suggest that the effects of crude oil contamination represent an imparing factor for S. glynnii coping with anthropogenic drivers (e.g. warming and acidification) and interfere with the delicate symbiont-host relationship of tropical corals. This is especially relevant in the coastal areas of northeastern Brazil where an oil spill event deposited crude oil on shallow water sediments with the potential to be resuspended to the water column by physical and/or biological activity, enhancing the risk of future coral bleaching events.

Ceratium furcoides is an invasive species that has caused ecological imbalance in several reservoirs in Brazil. This study investigates the main factors that may favor the occurrence of Ceratium furcoides blooms in a tropical reservoir from the Northeast Brazil, during an extreme drought season. Samples containing phytoplankton were collected monthly from February to September 2017. Quantitative analysis of C. furcoides was performed and the cell volume was estimated using geometric formulas. Mean biovolume of C. furcoides showed significant differences, ranging from 0.78 mm3 L-1 to 11.29 mm3 L-1 reported in March and September, respectively. Environmental parameters presented low oscillation throughout the study, except the conductivity. Significant relationships among the C. furcoides biovolume, water temperature and soluble reactive phosphate were observed. The findings reported here suggest that adverse conditions caused by a drought season did not negatively affect this species. Resumo Ceratium furcoides é uma espécie invasora que tem causado desequilíbrio ecológico em vários reservatórios no Brasil. Este estudo investiga os principais fatores que podem favorecer a ocorrência de florações de C. furcoides em um reservatório tropical do Nordeste do Brasil, durante um período de seca extrema. Amostras contendo fitoplâncton foram coletadas mensalmente de fevereiro a setembro de 2017. Análises quantitativas de C. furcoides foram realizadas e o volume celular estimado por meio de fórmulas geométricas. O biovolume médio de C. furcoides apresentou diferenças significativas, variando de 0,78 mm3 L-1 a 11,29 mm3 L-1 relatado em março e setembro, respectivamente. Os parâmetros ambientais apresentaram baixa oscilação ao longo do estudo, exceto a condutividade. Relações significativas entre o biovolume de C. furcoides, temperatura da água e fosfato reativo solúvel foram observadas. Os resultados relatados aqui sugerem que as condições adversas causadas por uma estação de seca não afetam negativamente esta espécie.

Dinoflagellates are photosynthetic protists commonly distributed in marine and freshwater environments and can be found in symbiotic associations. They are a significant primary producer and play a fundamental role in the functioning of aquatic ecosystems – especially for coral reefs. Dinoflagellates can produce a wide variety of secondary metabolites, and their toxins can affect fish, birds and mammals. In recent years these toxins have been found to have potential cytotoxic, anticancer, antibiotics, antifungals activities. This mini review covers the main genera of dinoflagellates, and challenges and advances in their cultivation in addition to prospects for development of dinoflagellates-based products., This study was financed in part by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil - Finance Code 001 and AOG is thankful to Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) (PQ 308063/2019-8)., {"references":["Anderson, D.M., Alpermann, T.J., Cembella, A.D., Collos, Y., Masseret, E. & Montresor, M. (2012). The globally distributed genus Alexandrium: multifaceted roles in marine ecosystems and impacts on human health. Harmful Algae 14: 10-35.","Bachvaroff, T.R., Adolf, J.E., Place & A.R. (2009). Strain variation in Karlodinium veneficum (Dinophyceae): toxin profiles, pigments, and growth characteristics. Journal of Phycology 45: 137-153.","Balech, E. (1989). Redescription of Alexandrium minutum Halim (Dinophyceae) type species of the genus Alexandrium. 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Proteins from microalgal biomass have become promising raw materials in several industrial segments. To evaluate growth performance and protein production under different nutritional conditions, Haematococcus pluvialis was grown in different culture media: BBM, RM, BG-11, and KM2. The cultures were inoculated at 105 cells mL-1, and submitted to a temperature of 24°C, in a continous photoperiod and irradiance of 40 µmol photons m-2 s-1. The highest cell density was observed when H. pluvialis was maintained in BG-11 medium (142 ± 30 × 104 cells mL-1), but no statistical difference was observed when comparing the results with those obtained when culturing this microalga in BBM (101 ± 14 × 104 cells mL-1) and RM (105 ± 5 × 104 cells mL-1) media. Also, the lowest cell density was found when cultivating H. pluvialis in KM2 medium (57 ± 9 × 104 cells mL-1), and there was no statistical difference for doubling time, growth rate and specific growth rate results between treatments. In addition, higher protein contents in H. pluvialis were reported for RM, BG-11, and KM2 culture media at 55.1 ± 5.6, 49.3 ± 3.6 and 58.4 ± 2.8%, respectively; and lower protein content was found using the BBM medium (31.1 ± 2.9%). The highest cell density and biomass were achieved at greater nitrogen availability and a higher nitrogen to phosphorus ratio. The results suggest that H. pluvialis is a potential species for protein production, and that BG-11 is the most suitable medium for growing this microalga as it allowed the achievement of highest biomass production and protein content among the media evaluated. Proteins from microalgal biomass have become promising raw materials in several industrial segments. To evaluate growth performance and protein production under different nutritional conditions, Haematococcus pluvialis was grown in different culture media: BBM, RM, BG-11, and KM2. The cultures were inoculated at 105 cells mL-1, and submitted to a temperature of 24°C, in a continous photoperiod and irradiance of 40 µmol photons m-2 s-1. The highest cell density was observed when H. pluvialis was maintained in BG-11 medium (142 ± 30 × 104 cells mL-1), but no statistical difference was observed when comparing the results with those obtained when culturing this microalga in BBM (101 ± 14 × 104 cells mL-1) and RM (105 ± 5 × 104 cells mL-1) media. Also, the lowest cell density was found when cultivating H. pluvialis in KM2 medium (57 ± 9 × 104 cells mL-1), and there was no statistical difference for doubling time, growth rate and specific growth rate results between treatments. In addition, higher protein contents in H. pluvialis were reported for RM, BG-11, and KM2 culture media at 55.1 ± 5.6, 49.3 ± 3.6 and 58.4 ± 2.8%, respectively; and lower protein content was found using the BBM medium (31.1 ± 2.9%). The highest cell density and biomass were achieved at greater nitrogen availability and a higher nitrogen to phosphorus ratio. The results suggest that H. pluvialis is a potential species for protein production, and that BG-11 is the most suitable medium for growing this microalga as it allowed the achievement of highest biomass production and protein content among the media evaluated.

A type of dredge was introduced as fishing gear along the extractive bank of Mangue Seco - PE from which the largest annual catch of Anomalocardia flexuosa in the world is extracted. This study was carried out with the objective of estimating the selectivity of the new fishing gear and quantitatively evaluating the length classes most compromised by the catches, especially considering 20 mm as the reference value. Specimens larger than this size are most likely to be mature. For the selectivity estimation, the methodology using codends (16 or 20 mm) and small meshed cover (2 mm) was used. To estimate the selectivity parameters, a logistic regression and the Bayesian approach were used. The transition between the state in which the specimen is invulnerable to the fishing gear and vulnerable occurs between 10 and 18 mm, using a 16 mm mesh, and using a 20 mm mesh, this transition is between 14 and 20 mm. Dredgers with 16 mm and 20 mm mesh compromise a large proportion of specimens smaller than 20 mm. If the intention is to protect this part of the population, measures such as total restriction of the 16 mm mesh and use of the 20 mm mesh should be necessary only in the months of less catching incidences, or increasing the mesh to 25 mm. RESUMO: Um tipo de draga foi introduzido como arte de pesca no banco extrativista de Mangue Seco - PE de onde se extrai a maior captura anual de Anomalocardia flexuosa do mundo. Este trabalho foi realizado com objetivo de estimar a seletividade do novo petrecho de pesca e avaliar quantitativamente quais são as classes de comprimento mais penalizadas nas capturas, tendo especialmente como referencial o valor de 20 mm. Exemplares maiores que esse tamanho tem elevada probabilidade de estarem maturos. Para estimativa da seletividade foi utilizado o método com uso de saco (16 ou 20 mm) e sobresaco (2 mm). Para estimativa dos parâmetros de seletividade foi utilizada regressão logística e abordagem bayesiana. A transição entre o estado em que o exemplar é invulnerável à arte de pesca e em que o mesmo seria quase com certeza capturado ocorre para malha de 16 mm entre 10 e 18 mm, enquanto para malha de 20 mm essa transição se dá entre 14 e 20 mm. As dragas com malha de 16 e 20 mm penalizam uma proporção grande de exemplares menores que 20 mm. Se a intenção é proteger essa parcela da população, seriam necessárias medidas como a restrição total da malha de 16 mm e uso da malha de 20 mm somente nos meses de menor incidência de recrutamento, ou o aumento da malha para 25 mm.

The aim of this study was to evaluate the bioremediation of effluents in the biofloc culture of shrimp juveniles using clams, seaweed and fish. Four treatments were considered: CLT – without biorem...

Recent advances in microalgae biotechnology have proven that these microorganisms contain a number of bioactive molecules, that can be used as food additives that help prevent disease. The green microalga Chlorella vulgaris presents several biomolecules, such as lutein and astaxanthin, with antioxidant capacity, which can play a protective role in tissues. In this study, we produced and analyzed a C. vulgaris functional alcoholic beverage (produced using a traditional Brazilian alcoholic beverage, cachaça, and C. vulgaris biomass). Assays were conducted in vitro by radical scavenging tests, and in vivo, by modeling cortical spreading depression in rat brains. Scavenging radical assays showed that consumption of the C. vulgaris alcoholic beverage had a DPPH inhibition of 77.2%. This functional alcoholic beverage at a concentration of 12.5 g L-1 significantly improved cortical spreading depression velocity in the rat brains (2.89 mm min-1), when compared with cachaça alone (3.68 mm min-1) and control (distilled water; 3.25 mm min-1). Moreover, animals that consumed the functional beverage gained less weight than those that consumed just alcohol and the control groups. These findings suggest that the C. vulgaris functional alcoholic beverage plays a protective physiologic role in protecting brain cells from the effects of drinking ethanol.

The aim of the present study was to evaluate the effect of different frequencies of the addition of the rotifer Brachionus plicatilis on growth, water quality, plankton composition, Vibrio, Bacillus and fungi (filamentous and yeast) in a nursery biofloc system with rice bran (anaerobic and aerobic) as an organic carbon source for Litopenaeus vannamei. Four treatments were used: BFT (biofloc without addition B. plicatilis); BFT-1F (addition of 30 org mL−1 of B. plicatilis on the 1st day); BFT-2F (addition of 30 org mL−1 of B. plicatilis on the 1st and 10th days) and BFT-4F (addition of 30 org mL−1 of B. plicatilis on the 1st, 10th, 20th and 30th days). The shrimp (PL10 3.0 ± 0.02 mg) were stocked at a density of 3000 m−3 and fed a commercial feed (45% crude protein and 9.5% lipids). The biofloc system was fertilized every three days for 42 days with anaerobic and aerobic rice bran processes using a microbial mix (0.1 g m−3) with 6.5 × 107 CFUs g−1 of Bacillus subtilis, 2.1 × 107 CFUs g−1 of B. licheniformis and 3.7 × 107 CFUs g−1 of Bacillus strains. The BFT-4F treatment led to higher (p

The aim of this study was to evaluate the effect of the addition of Chaetoceros calcitrans, Navicula sp. and Phaeodactylum tricornutum (diatoms) on phytoplankton composition and the growth of Litopenaeus vannamei postlarvae reared in a biofloc system. Four treatments were used: BFT (biofloc system without feed and no addition of diatoms); BFT-F (biofloc system with feed and no addition of diatoms); BFT-D (biofloc system with the addition of diatoms and no feed); and BFT-FD (biofloc system with the addition of feed and diatoms), all in triplicate. The shrimp (16 ± 0.02 mg) were stocked at 2500 postlarvae m−3 and fed a commercial feed. Diatoms were added on the 1st, 5th, 10th and 15th day at a density of 5 × 104 cells mL−1 for each species. No significant differences (P > 0.05) between treatments were observed for gross primary production, net ecosystem production and water column respiration rate. However, significant differences (P

The present study aimed to analyze the growth of Chlorella vulgaris in the effluent of a Biofloc Technology (BFT) system used in the Nile tilapia fingerlings farming. The conditions were cultivated by 10 days at 25 ± 2ºC, 90 μmol photons m−2 s−1 irradiance, under constant aeration (without addition of CO2), and with different BFT effluent proportions (0, 50, and 100%). After 24 hours of the inoculation that marked the beginning of the experiment, the development and multiplication of the cells were verified, demonstrating that the BFT effluent used in the Nile tilapia farming was favorable for the cultivation of the microalga Chlorella vulgaris. As expected, the Provasoli culture medium presented the best performance (1,520 ± 75 104 cells mL-1) in relation to the growth of the microalga. However, during the first four days of cultivation, C. vulgaris showed higher growth in treatments containing BFT effluent. C. vulgaris removed 93.6% of the nitrate contained in the BFT effluent. The results of the present study showed the potential use of C. vulgaris on Integrated Multi-Trophic Aquaculture with Nile tilapia fingerlings. In addition to removing nitrate and other nitrogen compounds, C. vulgaris biomass could be used to feed zooplankton or Nile tilapia larvae.

Anomalocardia brasiliana post-larvae were cultured for 28 days to evaluate the effect of stocking density on their growth and survival rate. Three stocking densities were tested 40, 80 and 160 post-larvae cm-2, in experimental units (2-L) with static cultivation system and total water renewal at each 48 hours. The experimental design was completely randomized with three treatments and three repetitions each. Stocking density of 40 post-larvae cm-2 reached 1 mm length within 24 days, while only 18% of the post-larvae at density of 80 post-larvae cm-2 reached 1 mm length in the same time. The density of 40 post-larvae cm-2 had the highest specific growth rate, 4.98±0.08% day-1. The survival rates of post-larvae at lower densities were significantly higher (53.24±4.60% and 52.95±3.32%, on 40 and 80 post-larvae cm-2, respectively) compared to higher stocking density (31.54±0.70%). In the cultivation of A. brasiliana post-larvae, stocking density must be managed during growth. The density of 160 post-larvae cm-2 can only be used until the post-larvae reach 600μm in length, then they should be at 40 post-larvae cm-2 density to keep the maximum daily growth rate. RESUMO: Pós-larvas de Anomalocardia brasiliana foram cultivadas por 28 dias para avaliar o efeito da densidade de estocagem no crescimento e taxa de sobrevivência. Três densidades de estocagem foram testadas: 40, 80 e 160 pós-larvas cm-2, em unidades experimentais (2 L) com sistema de cultivo estatístico e renovação total de água a cada 48 h. O delineamento experimental foi inteiramente casualizado com três tratamentos em triplicata. A densidade de estocagem com 40 pós-larvas cm-2 alcançou 1 mm de comprimento após 24 dias, enquanto apenas 18% das pós-larvas estocadas a 80 pós-larvas cm-2 atingiram 1 mm de comprimento no mesmo período. A densidade de 40 pós-larvas cm-2 apresentou a maior taxa de crescimento específico 4,98±0,08% dia-1. As taxas de sobrevivência de pós-larvas em baixas densidades foram significativamente maiores (53,24 ± 4,60% e 52,95 ± 3,32%, em 40 e 80 pós-larvas cm-2, respectivamente) em comparação com a maior densidade de estocagem (31,54 ± 0,70%). Os resultados sugerem que na criação de pós-larvas de A. brasiliana, a densidade populacional deve ser ajustada durante o crescimento. A densidade de 160 pós-larvas cm-2 só pode ser usada até que as pós-larvas atinjam o comprimento de 600µm; em seguida deve ser alterada para a densidade de 40 pós-larvas cm-2 para manter a taxa máxima de crescimento diário.

The purpose of this study was to produce Daphnia magna in wastewater from Tilapia farmed in a biofloc system, to evaluate three different carbohydrate:nitrogen ratios. The experiment was conducted for 30 days following a completely randomized experimental design, with the three treatments: C:N 10:1, C:N 15:1 and C:N 20:1, all fed with Chlorella vulgaris. The physical-chemical variables of the water analyzed were: temperature, dissolved oxygen (DO), pH, TAN, NO2 , hardness and alkalinity. The following growth variables of the Daphnia were also evaluated: Maximum average density (MAD), Maximum density day (MDD), Specific growth rate (SGR), Doubling time (DT) and yield (Y). The water quality variables remained in the range of ideal conditions for the species, presenting significant differences (p

O presente trabalho teve como objetivo avaliar o desempenho de alevinos de tilapia do Nilo, cultivados em tecnologia de bioflocos, utilizando diferentes densidades de inoculacao de Chlorella vulgaris. O delineamento experimental foi inteiramente casualizado, envolvendo o cultivo em sistema de bioflocos e quatro densidades de Chlorella vulgaris (0; 2,5; 5 e 10x104 cel mL-1), com quatro repeticoes cada. O trabalho teve duracao de 63 dias, sendo realizado em caixas com 40L de volume util, densidade de estocagem de 10 peixes por unidade experimental e peso medio inicial de aproximadamente 1,86 g. As variaveis de qualidade de agua nao apresentaram diferenca significativa entre os tratamentos, principalmente o nitrogenio da amonia total e do nitrito, que estiveram dentro do nivel aceitavel para o cultivo da especie. As variaveis de desempenho zootecnico nao foram afetadas pelas diferentes densidades de inoculacao da microalga, obtendo peso medio final de aproximadamente 21 g para os tratamentos e taxas de sobrevivencia superiores a 80%. Portanto para estas densidades de inoculacao da microalga Chlorella vulgaris, com frequencia semanal, nao apresentaram influencia no crescimento de alevinos de tilapia cultivada com bioflocos.

The temporal phytoplankton biomass variation at two Neotropical reservoirs during an extreme drought season were analyzed. Here we sought to evaluate the main abiotic factors involved in dynamics of phytoplankton during this drought period. The main difference between the reservoirs was the intensive fish and shrimp farming in one of the reservoirs. For quantitative analysis, sampling with bottles were carried out at an average depth of 0.5m. Water temperature, pH and electrical conductivity parameters were measured in situ and water samples were collected for dissolved inorganic nitrogen and soluble reactive phosphorus analyses. Aquaculture was probably one among the causes for the reservoirs were so different in the physical and chemical variables, as shown by the principal components analysis. The results showed specific groups dominance in both reservoirs. In the Cachoeira II reservoir, an invasive dinoflagellate, Ceratium furcoides, was present in all analyzed months, while, in the Saco I reservoir, cyanobacteria group represented more than 50% of phytoplankton biomass, mainly Microcystis aeruginosa and Dolichospermum sp. In two reservoirs precipitation, soluble reactive phosphorus and electrical conductivity were positively related with phytoplankton. Phytoplankton biomass was considerably larger in the Cachoeira II reservoir, due to the greater size and biovolume of the dominant dinoflagellate. These findings suggest that species dominance in extreme drought events may be favored.

Microalgae are considered one of the most promising raw materials for the development of high value products for pharmaceuticals, nutraceuticals, and cosmetic industries, as well as being potential sources of protein, vitamins, and minerals for human consumption. Hence, the present research focuses extraction of antioxidant and antimicrobial compounds from Scenedesmus subspicatus using solvents of different polarities. Different solvents such as ethanol, methanol, butanol, acetone, dimethyl sulfoxide, and water were used to extract compounds from the green microalgae S. subspicatus and then they were examined for phytochemical screening, antioxidant activity, and antimicrobial properties. In vitro free radical quenching and total antioxidant activity of extracts were investigated with 1,1-diphenyl-2-picryl hydrazyl and compared with catequin and gallic acid as positive controls. The antimicrobial activity was evaluated in gram-negative and gram-positive bacteria. Aqueous extracts and dimethyl sulfoxide presented better performance in phytochemical analysis. This result showed consistency in the sequential tests. The antioxidant activity was also better using the two solvents cited above. The extracts acetone, water, and dimethyl sulfoxide showed ability to inhibit the growth of Bacillus subtilis. However, only dimethyl sulfoxide inhibited the growth of Klebsiella pneumoniae and Escherichia coli. Use of the aqueous extract, proven its effectiveness, is an economic protocol and avoids the use of toxic substances.

A 42-day trial was conducted to evaluate the effects of a low-salinity biofloc system with different stocking densities on water quality and zootechnical performance of Nile tilapia fingerlings (10 g/L). Four treatments were tested at different densities: 500 fish/m³, 750 fish/m³, 1,000 fish/m³ and 1,250 fish/m³, all in triplicate. Fingerlings of Oreochromis niloticus (initial mean weight of 1.17 ± 0.05 g) were stocked in twelve experimental black-plastic tanks (40 L) with no water exchange during the experimental period. Molasses was added daily to the system at 30% of the amount of feed, and fish were given four daily rations of a formulated feed composed of 36% crude protein and 9% lipids. Water quality variables (dissolved oxygen, pH, salinity, TAN, NO 2 , NO 3 and PO 4 3 ) did not demonstrate significant differences between the treatments. However, significant influences (α ≤ 0.05) of the stocking densities were observed for total suspended solids, settleable solids, final weight, yield, and protein efficiency ratio. The results showed survival over 96%, final weight values between 12 and 18 g, yield between 9.49 and 15.27 kg/m 3 , water consumption of 52 to 101 L/kg fish, and total time of settling chambers between 238 and 305 h/kg fish. These results indicate a negative effect of stocking density on final weight, survival, alkalinity, NO 2 , PO 4 3 and water consumption, and a positive effect on yield in Nile tilapia fingerling culture (1-20 g) in a low-salinity biofloc system with densities up to 1000 fish/m³.

The purpose of this study was to determine the moment of the year for the oyster recruitment and define the type of collector and environmental conditions that maximize recruitment. Collections were conducted, during 12 months, on Amazon Macrotidal Mangrove at two different sites: raft (point I) and mangrove (point II). In each location three types of collectors were used (1) transparent PET bottles, (2) green PET bottles, and (3) PVC sheets, each with three replicates. Spats were counted and measured at 45-day intervals, while the environmental data were measured every two weeks. Identification of oyster species occurred by genetic testing (multiplex PCR) by randomly selecting individuals by sampling. Results indicated spat capturing was significantly influenced by the collector type, location and period of collection (P

The purpose of this study was to evaluate the effect of Brachionus plicatilis and Navicula sp. addition on growth performance, Vibrio count, immunological responses and resistance to white spot syndrome virus (WSSV) of Litopenaeus vannamei in nursery biofloc system. The study was divided into two phases and four treatments were examined in the first phase: BFT (biofloc); BFT-N (addition of 10×104 cells mL−1 of Navicula sp.); BFT-B (addition of 30 org mL−1 of B. plicatilis) and; BFT-BN (addition of 10×104 cells mL−1 of Navicula sp. and 30 org mL−1 of B. plicatilis), all in triplicate and; the second phase included a viral challenge, also in triplicate. Shrimp (PL10, 2 ± 0,01 mg) were reared in biofloc system (fertilized with inorganic and anaerobic and aerobic carbon process with a microbial mix), for 45 days at a density of 3000 shrimp m-3, with controlled temperature, without water exchange and fed with commercial feed. The diatoms and rotifers were added every 10 days, and at the end, shrimp performance, water quality, Vibrio count and total hemocyte count were evaluated. After 45 days, 300 shrimp m−3 were challenged with WSSV (2.2 × 107 copies of WSSV μL−1 of DNA) for 9 days. The BFT-N, BFT-B and BFT-BN treatments had higher values of final weight (1.02 to 1.16 g) and yield (2.85 to 3.30 kg m−3) which were higher than the BFT (0.86 g and 2.46 kg m−3). There were no differences in water quality among treatments. Vibrio count from water samples was significantly lower at the end of experiment with significant decrease of non-sucrose-fermenting gram-negative bacteria. However, for hepatopancreas, the Vibrio count was significant higher at the end, however with significantly increase of sucrose-fermenting gram-negative bacteria (98 to 100%). There was no significant difference between the THC and hyalyne count for all treatments. Massive mortality rate was firstly achieved in BFT and BFT-B treatments in the second phase. However, all treatments reported complete mortality and WSSV infection was confirmed by nested-PCR and histopathologically, with lesions suggestive of WSD (presence of nodules and tissue deformations). The Navicula sp. and B. plicatilis addition contributed to better performance parameters of shrimp in the nursery biofloc system, although there was no significant effect on the WSSV resistance of shrimp. Absence of tissue degeneration in WSSV infected shrimp from BFT-N treatment indicated benefit of using diatoms under standardized conditions.