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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 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.

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.

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...

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

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.

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.

In recent years, the coculture of organisms from different trophic levels has been practiced to improve water quality and nutrient consumption. In this context, this study evaluated the effect of Crassostrea stocking density on zootechnical performance and water quality of Litopenaeus vannamei reared in a multitrophic biofloc system during the nursery phase. The experimental design was completely randomized with four treatments: control (shrimp monoculture) and three treatments with oysters (3.21 ± 1.26 cm) at densities of 100, 200 and 300 oyster m−2, for 45 days. Water quality, zootechnical performance parameters of shrimp and oysters, proximate composition of microbial flocs, Vibrio count from water, shrimp and oysters samples and total hemocyte counts from shrimp and oyster samples were evaluated. For water quality, multitrophic biofloc system treatments had the lowest amounts of settleable solids, resulting in lower settling chamber use than the control. However, a high density of oysters (300 oysters m−2) increased total ammonia nitrogen and nitrite-N levels, which had maximum values of 4.01 and 4.63 mg L−1, respectively. The final average weight and cumulative growth of oysters were 16.23 ± 3.45 g and 18.91 ± 5.24%, respectively, corresponding to an average growth of 4.07 ± 0.34 mm month−1. In shrimp performance, the higher density treatment (300 oysters m−2) had the lowest values of final weight and yield (0.94 ± 0.03 g and 2.26 ± 0.05 Kg m−3) and the lowest nutritional quality of the microbial floc (14.96% protein and 3.71% lipid). The Vibrio count was significantly lower in all the multitrophic biofloc system treatments compared to the control, with an average reduction of 37.32% in water and 75.69% in shrimp hepatopancreas. Stocking densities of up to 200 oysters m−2 did not affect shrimp growth in the multitrophic biofloc systems evaluated. The multitrophic biofloc system used in this research is a viable option for controlling nitrogen compounds and solids and reducing Vibrio in a shrimp biofloc system during the nursery phase.

In the farmed whiteleg shrimp ( Litopenaeus vannamei ), Infectious myonecrosis virus (IMNV) accounts for 70% of the cumulative mortality during the growout cycle. Although the horizontal transmission of IMNV has been demonstrated, vertical transmission remains unknown, which may be a crucial factor to the prevention of IMNV from one generation to the next. Thus, the aim of the present study was to determine the possibility of the vertical transmission of IMNV by experimental infection in SPF and non-SPF L. vannamei broodstocks using an intramuscular procedure. Evaluations involved the use of molecular methods (Real-time PCR and conventional PCR) for spermatophores, ovaries and eggs tissues. The effect of IMNV infection on sperm viability was also evaluated. Conventional PCR detected IMNV in spermatophores, mature ovaries and muscle tissue from experimentally infected specific pathogen-free (SPF) broodstock. Real-time PCR confirmed IMNV replication in all samples (spermatophores, mature ovaries, muscle tissue and eggs — fertilized or not) from naturally and experimentally infected non-SPF broodstock. No significant difference in viral load of the reproductive organs/tissues was found between naturally or experimentally infected shrimp (both sexes) (p ≥ 0.05). However, a significant difference was found regarding mean viral load in the muscle tissue of all shrimps (males and females) in comparison to other tissues, with dissimilar viral load values for naturally and experimentally infected muscle tissue for both sexes (p ≤ 0.05). With regard to spawning, all infected females spawned and no significant difference was found in the viral load of eggs produced by naturally and experimentally infected females. The eggs were classified as two morphological types (type B and A 2 ) based on morphology and post-spawning development. Sperm viability of experimentally infected males was not determined due to the low cell density, whereas mean viability among naturally infected males was 82%. In the control group, mean sperm viability was 91%. The results suggest that IMNV can be transmitted vertically in L. vannamei . However, nauplii did not hatch out, which prevented a better understanding of the mechanisms by which eggs become infected following spawning (egg surface or by transovarial transmission). Nonetheless, the 100% positive samples from ovaries and eggs and the low percentage of viable cells from naturally infected males suggest that females are the primary source of the vertical transmission of IMNV to eggs. Statement of relevance This study reports the first scientific evidence of IMNV vertical transmission in L. vannamei . The study suggests the use of IMNV-free broodstock as an effective prevention measure in order to minimize propagation in L. vannamei farming operations.

A 16-week trial was carried out to evaluate an intensive culture system of Litopenaeus vannamei in commercial ponds with zero water exchange. Two management strategies were used: one with the addition of molasses (ML) and the second with commercial probiotic and molasses (PML), each with four replicates. Shrimp L. vannamei (2.09 ± 0.3 g) were stocked in 2.6 ha ponds without liners at a density of 98 shrimp m-2. The commercial probiotics used with molasses was a mixture of Bacillus spp. and Lactobacillus sp. After 16 weeks, no significant differences were found in mean dissolved oxygen, temperature, salinity, pH, total heterotrophic bacteria and zootechnical parameters (yield, FCR, survival and final weight) between the two management strategies. Total ammonia nitrogen concentration (53 to 69%) was the highest inorganic nitrogen compound. There were no significant differences between its concentrations in the two management strategies. The addition of molasses and probiotics are important management strategies for increased shrimp growth in an intensive system in ponds with zero water exchange, however, molasses is cheaper than the probiotics. Molasses inputs were based on a percentage of the daily feed allotments (by weight) and application rates of 30% of total daily feed in combination with commercial probiotics in intensive ponds without liners with zero water exchange was not sufficient to recycle all nitrogen waste with 10 HP ha-1.

The aim of this study was to evaluate the effect of the addition of Navicula spp. and Brachionus plicatilis on water quality and growth of postlarvae shrimp Litopenaeus vannamei reared in a biofloc system. Four treatments were considered: a control (biofloc system – BFT); BFT with the addition of Navicula spp. (BFT-N); BFT with the addition of Brachionus plicatilis (BFT-B) and BFT with the addition of Navicula spp. and Brachionus plicatilis (BFT-NB), each in triplicate. Shrimp (16.2 ± 0.03 mg) were stocked at a density of 2500 shrimp m−3 and plankton were added on days 1, 5, 10, 15, 20, 25 and 30 at a density of 5 × 104 cells mL−1 (Navicula spp.) and 30 organisms L−1 (Brachionus plicatilis). The shrimp were fed a formulated feed in four daily rations composed of 40% crude protein and 8% lipids. Significant differences between treatments were observed for final weight, yield, feed conversion ratio, specific growth rate, protein efficiency ratio and protein content of the shrimp. The combined plankton addition of Navicula spp. and B. plicatilis had better performance parameters, indicating their benefit as natural food sources for postlarvae L. vannamei in biofloc systems.

Na presente pesquisa avaliou-se o efeito da relação carbono/nitrogênio (C:N) na qualidade da água, produtividade e composição centesimal dos alevinos de Oreochromis niloticus durante 58 dias de cultivo. O desenho experimental consistiu em quatro tratamentos: um sistema convencional (controle) e três sistemas de biofloco (CN10, CN15 e CN20). Foram utilizadas 12 unidades experimentais de 0,04 m3 com 30 peixes (750 peixes m-3) com peso médio individual de 1,55 ± 0,01 g. Verificou-se a existência de interação entre os parí­¢metros de qualidade da água do sistema de biofloco e os parí­¢metros produtivos dos alevinos de tilápia. O tratamento CN10 apresentou baixa produção de sólidos sedimentáveis, 38,61 ± 0,54 mL L-1 (p

An indoor trial was conducted for 42 days to evaluate water quality, Vibrio density and growth of Litopenaeus vannamei in an integrated biofloc system (IBS) with Gracilaria birdiae. Four treatments were used, each in triplicate: Control (monoculture shrimp); IBS 2.5 (L. vannamei and 2.5 kg wet weight seaweed m−3); IBS 5.0 (L. vannamei and 5.0 kg wet weight seaweed m−3) and IBS 7.5 (L. vannamei and 7.5 wet weight seaweed m−3). Shrimp individuals (0.34 ± 0.01 g) were stocked at a density of 500 shrimp m−3. No water exchange was carried out during the experimental period. Molasses was added once a day as an organic carbon source to maintain the C:N ratio at 12:1. The IBS significantly decreased (P

Effects of different microalgal diets on the growth and on the survival of Anomalocardia brasiliana larvae between trochophore and pediveliger stages were evaluated. Diets were evaluated in two separate experiments. The first tested the microalgae Isochrisys galbana (Ig), Phaeodactylum tricornutum (Phaeo), Chaetoceros calcitrans (Cca) and the combinations (Ig+Cca), (Ig+Phaeo) and (Cca+Phaeo). The second tested the microalgae C. calcitrans (Cca), Pavlova lutheri (Pl) and the combination (Cca+Pl). When provided alone, I. galbana resulted in survival and growth rates lower than the rest of the diets, and the best results achieved were obtained with P. tricornutum and C. calcitrans supplied alone or combined with other microalgae. However, in the second experiment the diet Cca+Pl resulted in better growth and survival rates (261.67 ± 9.64 μm and 31.50 ± 0.87%) than all diets tested in both experiments, therefore it is recommended for A. brasiliana larvae.

A trial was conducted for 42 days to evaluate the effects of two commercial feeds with high and low crude protein content on the performance of white shrimp Litopenaeus vannamei cultivated in an integrated biofloc system with the seaweed Gracilaria birdiae. The experiment had a 2 × 2 factorial design (a biofloc monoculture or an integrated system with 32% (low) or 40% (high) crude protein content) with the following treatments: IS32 (an integrated system using low protein commercial feed); IS40 (an integrated system using high protein commercial feed); M32 (a monoculture system using low protein commercial feed); and M40 (a monoculture system using high protein commercial feed), all in triplicate. Shrimp individuals (0.23 ± 0.04 g) were stocked at a density of 500 shrimp/m3 and no water exchange was carried out during the experimental period. No significant influence (p > 0.05) was found to be caused by the integrated system or the crude protein levels on water quality. However, a significant influence (p < 0.05) was found for final weight (3.21–4.12 g), weight gain (2.97–3.89 g), yield (1.39–1.96 kg/m3) and feed conversion ratio (1.47–1.74). Growth was similar in IS32, M40 and IS40, indicating that crude protein levels can be reduced with no adverse effect on shrimp performance variables in integrated biofloc systems with G. birdiae.