Brazilian Flounder Research Articles

Acute toxicity and sublethal effects of nitrite on oxidative stress in early juvenile Brazilian flounder, Paralichthys orbignyanus

This study evaluated the acute toxicity and sublethal effects of nitrite on oxidative stress parameters in early juvenile Brazilian flounder, Paralichthys orbignyanus. Fish were exposed to six concentrations of nitrite: 20, 40, 80, 170, 330 and 550 mg NO2−N-L−1, plus a control with no added nitrite, all in triplicate for 96 h. Every 24 h, the tanks were monitored to check possible mortality to estimate the LC50. At the end of the experiment, fish were sampled for stress oxidative analysis. All fish exposed to 550 mg NO2−N-L−1 died within the first 24 h. The LC50 ranged from 427.8 to 393.1 mg NO2−N-L−1 for 24 and 96 h respectively. The total antioxidant capacity against peroxyl radicals (ACAP) showed a gradual reduction in fish exposed to nitrite levels from 170 mg NO2−N-L−1. The glutathione S-transferase (GST) activity was higher in 80, 170 and 330 mg NO2−N-L−1. The non-proteic (NPSH) and proteic (PSH) thiols levels were higher in 170 and 330 mg NO2−N-L−1 compared with the control, 20 and 40 mg NO2−N-L−1. Lipid peroxidation (LPO), as indicated by the thiobarbituric acid reactive substances (TBARS) level, was significantly higher in fish exposed to 330 mg NO2−N-L−1 than the control and 20 mg NO2−N-L−1. Moreover, a pro-oxidant condition was induced when P. orbignyanus were exposed to concentrations from 80 mg NO2−N-L−1, which was evidenced by alterations in the antioxidant system and increased levels of LPO. Therefore, it is recommended that the nitrite concentration do not exceed 40 mg NO2−N-L−1 in order to avoid oxidative stress for early juvenile Brazilian flounder.

From fish-markets to restaurants: Substitution prevalence along the flatfish commercialization chain in Brazil

Over the last few years, molecular species identification has revealed high levels of seafood mislabelling, which has generated public concern. The success of regulatory efforts depends on the accurate estimation of species substitution across multiple points in the supply chain. Flounders are among the most popular and highly valued seafood products marketed in Brazil. However, substitution rates are poorly known in large consumer markets such as Rio de Janeiro. We used sequences of mitochondrial genes to estimate the prevalence of mislabelling in the Brazilian flounder trade. Nearly 50 % (130/260) of fish samples analysed were mislabelled. The prevalence of mislabelling varied across the commercialisation chain and was high in street markets (61 %) and restaurants (82 %), when compared to fishmongers (38 %) and supermarkets (22 %). The most common species used as substitutes were Pangasianodon hypophthalmus (75 %) and Xystreurys rasile (17 %). We show that the 2015 revisions were ineffective in reducing mislabelling and curb inspection by omitting frequently commercialized local pleuronectiforms, such as X. rasile. Substitute species were usually lower-priced, indicating an economic motivation for mislabelling. Our findings reinforce the need for updated and consistent labelling regulations and more stringent control of flounder sales in street markets and restaurants.

Oxidative stress and antioxidant responses in juvenile Brazilian flounder Paralichthys orbignyanus exposed to sublethal levels of nitrite

This study evaluated the effects of short-term exposure to sublethal levels of nitrite on oxidative stress parameters and histology of juvenile Brazilian flounder Paralichthys orbignyanus. An assessment of fish recovery was also performed. Fish were exposed to 0.08 (control), 5.72, 10.43, and 15.27 NO2-N mgL-1 for 10days followed by the same recovery time. Gill, liver, and muscle samples were collected after 1, 5, and 10days of exposure and after recovery for the measurement of antioxidant capacity against peroxyl radicals (ACAP), glutathione-S-transferase (GST) activity, content of non-protein (NPSH) and protein thiols (PSH), and lipid peroxidation levels by thiobarbituric acid-reactive substances (TBARS) content. Nitrite exposure induced alterations which compromised the overall antioxidant system (reduced ACAP and GST activity) and enhanced oxidative damage in lipids and proteins. Increases in GST activity and NPSH and PSH contents were also demonstrated. The recovery period allowed for resumption of basal levels for all (treatment 5.72 NO2-N mgL-1) or some of the evaluated parameters (other treatments). In conclusion, exposure to nitrite concentrations from 5.72 to 15.27 NO2-N mgL-1 induced oxidative stress and antioxidant responses in juvenile Brazilian flounder. The 10-day recovery period was sufficient for a complete resumption of basal physiological condition of fish exposed to concentrations of up to 5.72 NO2-N mgL-1.

Secondary Stress Responses in Juvenile Brazilian Flounder, Paralichthys orbignyanus, throughout and after Exposure to Sublethal Levels of Ammonia and Nitrite

AbstractThis study investigated the secondary stress responses of Paralichthys orbignyanus exposed to ammonia and nitrite and after recovery. Fish were exposed to 0.12, 0.28, and 0.57 mg NH3‐N/L, or 5.72, 10.43, and 15.27 mg NO2‐N/L for 10 d followed by the same time length for recovery. Ammonia‐ and nitrite‐free water was used as a control treatment. Blood samples were collected after 1, 5, and 10 d of exposure and after recovery. Fish exposed to ammonia presented lower and higher glucose levels after 10 d of exposure and recovery, respectively. Ammonia induced initial and transient ionic disturbances and metabolic alkalosis. Nitrite exposure caused hyperglycemia, increased plasma K+ levels, and respiratory alkalosis, whereas metabolic acidosis was observed after recovery. Increased proportion of monocytes and/or granulocytes and reduced number of lymphocytes were demonstrated in fish exposed to 0.28 mg NH3‐N/L (Day 1) and 10.43 mg NO2‐N/L (Day 5) and after recovery in the 0.28 and 0.57 mg NH3‐N/L treatments. Exposure to ammonia decreased the proportion of granulocytes on Day 5. In conclusion, exposure to concentrations at 0.12 mg NH3‐N/L and 5.72 mg NO2‐N/L provoked physiological disorders in Brazilian flounder. Nonetheless, fish exposed to 5.72 mg NO2‐N/L following a 10‐d recovery period showed complete resumption of homeostasis.

Characterization of digestive enzymes from captive Brazilian flounder Paralichthys orbignyanus.

Knowledge of specific enzyme activity, along with animal habits and digestive capacity is essential in formulating an appropriate diet for any species. In this study, we evaluated and characterized the activity of digestive enzymes present in the liver, intestine, and stomach of Paralichthys orbignyanus. The effects of pH and temperature on enzyme activity were also evaluated via the use of specific substrates. The use of specific substrates and inhibitors showed strong evidence of the presence of trypsin (BApNA= 0.51 ± 0.2 mU mg-1), chimotrypsin (SApNA= 2.62 ± 1.8 mU mg-1), and aminopeptidases (Leu-p-Nan =0.9709 ± 0.83 mU mg-1) in the intestine. Optimum pH for the activity of trypsin, chemotrypsin, leucino aminopeptidase, amilase, and pepsin were 9.5, 9.0, 8.0, 7.5, and 3.5, respectively, while optimum temperatures were 50, 50, 50, 40, and 45 °C, respectively. These results provide additional information regarding the biology of Brazilian flounder and can be used as a basis for further studies regarding fish feeding physiology.

Ammonia exposure and subsequent recovery trigger oxidative stress responses in juveniles of Brazilian flounder Paralichthys orbignyanus.

The effects of ammonia exposure and recovery on oxidative stress parameters and histology of juvenile Brazilian flounder Paralichthys orbignyanus were evaluated. The fish were exposed to 0.12, 0.28 and 0.57mgNH3-NL-1, plus a control, for 10days followed by the same recovery time in ammonia-free water. Gill, liver and muscle samples (n=9) were collected after 1, 5 and 10days of exposure and after recovery for oxidative stress analysis (antioxidant capacity against peroxyl radicals (ACAP); glutathione S-transferase (GST) activity; lipoperoxidation levels measured through thiobarbituric acid reactive substances (TBARS) content). For histological assessment, gill, liver and brain samples were collected. Exposure to all NH3-N concentrations induced different time- and dose-dependent changes in oxidative stress parameters. Reduced antioxidant capacity of the liver and muscle and enhanced TBARS levels in the gills and liver were demonstrated. Differently, a high ammonia concentration elicited lower hepatic TBARS levels. Enhanced GST activity in all organs and increased antioxidant capacity of the gills were also observed. No ammonia-induced histopathological effects were demonstrated. After recovery, most parameters (liver ACAP, GST activity in the muscle and liver and TBARS in the gills) returned to baseline levels. However, liver TBARS and gill GST activity remained altered 0.57mgNH3-NL-1 treatment. The recovery period also led to a decrease in gill antioxidant capacity and an increase in muscle antioxidant capacity. In conclusion, a concentration of 0.12mgNH3-NL-1 induces oxidative stress and antioxidant responses in juvenile Brazilian flounder. Moreover, a 10-day recovery period is not sufficient to restore fish homeostasis.

Oxidative stress parameters in juvenile Brazilian flounder Paralichthys orbignyanus (Valenciennes, 1839) (Pleuronectiformes: Paralichthyidae) exposed to cold and heat shocks

The aim of this study was to determine oxidative stress parameters in the liver and gill of Brazilian flounder juveniles (307.0 ± 16.0 g and 30.0 ± 4.0 cm) submitted to different water temperature (17.1, 23.0 and 28.8ºC) for 72 h and maintained at salinity 25‰. After the acclimation of 7 days, in 23ºC, fish were transferred to 200 L tanks containing seawater (salinity 25‰) at 28.8ºC (heat shock), 17.1ºC (cold shock) or 23.0ºC (control), five replicates (five fish tank-1). The sampled collection occurred in 0 (pre-challenge), 3, 24, 48 and 72 h after temperature shock. Flounder exposed to 17.1ºC and 28.8ºC showed significantly higher TBARS levels and GST activity in the liver post-exposition (PE) in relation to the control (23ºC). CAT activity in liver present a significantly increase at 17.1ºC, in first 48 h, and subsequently decrease in 72 h PE in relation to 28.8ºC. The gills of flounder showed significantly higher TBARS levels, GST and CAT activity when submitted at 17.1 and 28.8ºC in relation to 23.0ºC. There were observed changes in lipid peroxidation levels (LPO), CAT and GST activities in the liver and gill of Brazilian flounder in response to reactive oxygen species (ROS) produced by thermal shocks.

Neuropeptide Y gene expression around meal time in the Brazilian flounder Paralichthys orbignyanus

Neuropeptide Y (NPY) is considered the major stimulant for food intake in mammals and fish. Previous results indicate that NPY is involved in the feeding behaviour of the Brazilian flounder, Paralichthys orbignyanus. In this study, we evaluated hypothalamic NPY expression before (-2 h), during (0 h) and after feeding (+2 h) in two independent experiments: (1) during a normal feeding schedule and (2) in fish fasted for 2 weeks. During normal feeding, changes in the levels of NPY mRNA were periprandial, with expression levels being significantly elevated at meal time (P less than 0.05) and significantly reduced 2 h later (P less than 0.05). Comparing the fasting and unfasted groups, NPY mRNA levels were significantly higher (P less than 0.05) at -2 h and +2 h in the fasting group, but there was no difference at 0 h. In addition, the higher NPY mRNA levels that were observed in the fasting group were maintained throughout the sampling period. In summary, our results show that NPY expression was associated with meal time (0 h) in food intake regulation.

Processing yield of wild-caught and indoor-reared Brazilian flounderParalichthys orbignyanus

Summary The aims of this work were to evaluate the fillet yield and the skin area production of wild-caught (male × female) and indoor-reared male Brazilian flounder Paralichthys orbignyanus. Fillet yield of wild-caught Brazilian flounder is high, averaging 53.4 ± 0.7 and 51.2 ± 0.6% to female and male, respectively. However, indoor-reared male flounder show even higher (P < 0.05) fillet yields of 59.4 ± 0.1%. Flounder weighing around 500 g should yield a skin area of ca. 450 cm2, representing an important sub-product that can be used in the fashion industry. The results of the present study emphasize the potential for culture and use of sub-products of the Brazilian flounder.

Micobacteriose por Mycobacterium marinum em "linguado" Paralichthys orbignyanus e em "barber goby" Elacatinus figaro: diagnóstico histopatológico e imuno-histoquímico

As micobacterioses afetam várias espécies de peixes, tanto comerciais como ornamentais. É uma enfermidade sistêmica com formação de granulomas, conhecida como micobacteriose de peixes. O desenvolvimento da aquicultura tem aumentado o número de casos com essa enfermidade que muitas vezes é de difícil diagnóstico. Neste trabalho apresentamos dois casos de micobacterioses em Paralichthys orbignyanus e Elacatinus figaro provenientes do Laboratório de Piscicultura Estuarina e Marinha da Universidade Federal do Rio Grande (FURG). As micobactérias de peixes possuem menos ácidos graxos que as de mamíferos, por isso foi utilizado o protocolo de coloração de Fite-Faraco, uma vez que o protocolo de coloração clássico de Ziehl Neelsen pode resultar em falsos negativos. Para determinar o tipo de micobactéria foi utilizada a imuno-histoquímica com a qual se pode diagnosticar a presença de Mycobacterium marinum. A enfermidade pode ser transmitida para o homem e com esse trabalho ressalta-se a necessidade de fazer o diagnóstico correto e implantar medidas de proteção para as pessoas que estão em contato com os peixes infectados.

NPY and sbGnRH gene expression in juvenile and adult male Brazilian flounder Paralichthys orbignyanus

The objective of this study was to evaluate neuropeptide Y (NPY) and sea bream gonadotropin-release hormone (sbGnRH) gene expression in juvenile and adult males of Brazilian flounder. Hypothalamuses from fish were sampled for total RNA extraction. After cDNA synthesis, real-time PCR was used to measure gene expression. NPY showed approximately 2-fold increases in their mRNA levels while sbGnRH showed 3-fold increases in adult fish. These results suggest that these peptides could be involved on hypothalamic regulation of Brazilian flounder sexual maturation.

Clonagem e avaliação da expressão gênica do sbGnRH em machos juvenis e adultos de linguado, Paralichthys orbignyanus

Este estudo buscou clonar o cDNA do sbGnRH, identificar sua expressão em diferentes tecidos do linguado, bem como avaliar possíveis diferenças no RNA mensageiro (RNAm) desse gene no cérebro de linguados machos juvenis e adultos. Por meio da RT-PCR, demonstrou-se pela primeira vez, a clonagem da região codificadora do sbGnRH contendo 297 nucleotídeos do cérebro do linguado. A expressão do sbGnRH foi detectada em vários tecidos periféricos. Foram detectados níveis mais elevados de RNAm do sbGnRH no hipotálamo dos animais adultos. Estes resultados sugerem que o sbGnRH está envolvido na puberdade do linguado.

Sperm quality of Brazilian flounder Paralichthys orbignyanus throughout the reproductive season

The aim of this study was to evaluate the sperm quality of Brazilian flounder Paralichthys orbignyanus throughout its reproductive season. Sperm was collected at the beginning, middle and end of the breeding period. Spermatozoa density was maximum at the beginning (12.7 ± 0.92 × 109 cells mL−1) and at the end (11.8 ± 0.39 × 109 cells mL−1) of the breeding season (P<0.05). Sperm production and the percentage of spermatozoa moving fast forward increased significantly towards the end of the breeding season (P<0.05). The mean duration of progressive motility of spermatozoa was around 10 min. No difference was observed during the reproductive season in the percentage of motile cells, pH, osmolality and K+, Cl− and Mg2+ concentrations in seminal plasma. The concentration of Na+ increased throughout the breeding season, reaching 174.62 ± 12.68 mmol L−1 at the end (P<0.05). There was a decline in the concentration of Ca2+ (12.31 ± 3.08 mmol L−1) in the middle of the breeding season, which coincided with the shortest motility duration of spermatozoa. The information reported in this study should help to improve management and optimize the development of protocols for short-term storage and cryopreservation of Brazilian flounder semen.

Identification, tissue distribution and evaluation of brain neuropeptide Y gene expression in the Brazilian flounder Paralichthys orbignyanus

Neuropeptide Y (NPY) is one of the most potent stimulants of food intake in vertebrates, mammals and fish. However, the present knowledge about feeding behaviour in fish is still limited and based on studies in a few species. The Brazilian flounder Paralichthys orbignyanus is being considered for aquaculture, and it is important to understand the mechanisms regulating feeding in order to improve its performance in captivity. The objectives of this study were to clone NPY cDNA, evaluate the mRNA levels in different tissues of flounder, and also evaluate brain NPY expression to associate food intake with NPY expression levels. A 597 bp NPY cDNA was cloned from Brazilian flounder brain. NPY expression was detected in all the peripheral tissues analysed. No significant differences were observed in brain NPY gene expression over 24 h after food intake at a temperature of 15 +or- 3 degrees C. No correlation was observed among plasma glucose, total protein, cholesterol, triglycerides and NPY expression levels during this 24 h period. On the other hand, mRNA levels were increased after two weeks of fasting at elevated temperatures. Our results suggest that NPY mRNA levels in Brazilian flounder are affected by temperature.

Increased growth hormone (GH), growth hormone receptor (GHR), and insulin-like growth factor I (IGF-I) gene transcription after hyperosmotic stress in the Brazilian flounder Paralichthys orbignyanus

Growth hormone (GH) action is the result of an intracellular cascade initiated just after its interaction with the growth hormone receptor (GHR) located on the surface of target cells. This cascade culminates with the transcription of target genes, such as the insulin-like growth factors (IGFs), which are responsible for most GH biological effects. In addition to its central role in growth, fish GH is also involved with osmoregulatory control. Within this context, the objective of the present work was to isolate GH, GHR, and IGF-I cDNAs from the Brazilian flounder Paralichthys orbignyanus and evaluate whether these genes are induced by hyperosmotic stress. The obtained results indicated that GH mRNA had a significant peak only 24 h after hyperosmotic stress. In gills, GHR mRNA was significantly increased after 7 days. In liver, GHR and IGF-I mRNAs were significantly increased in 72 h and both reached even higher levels after 7 days. These results indicate that hyperosmotic stress can increase GH sensitivity in the gills and liver of P. orbignyanus and, consequently, improve IGF-I production. The management of this parameter could be useful in achieving better growth performance for this and other commercially important species in which GH has a direct correlation with osmoregulatory mechanisms.

Produção de juvenis do linguado Paralichthys orbignyanus: efeito da duração do período de co-alimentação durante o desmame

O desmame, ou seja, a substituição do alimento vivo por alimento inerte é uma etapa crítica para a produção de alevinos de peixes marinhos. Este trabalho teve por objetivo avaliar o efeito do período de co-alimentação (alimento vivo e inerte) sobre a sobrevivência, o crescimento e os custos de produção de juvenis do linguado Paralichthys orbignyanus. Durante o período de co-alimentação, os juvenis (idade inicial 32 dias) receberam Artemia enriquecida juntamente com ração. Foram testados três períodos de co-alimentação: 15, 20 e 25 dias, mais um grupo controle alimentado com Artemia enriquecida. Ao final do experimento (76 dias), os juvenis alimentados exclusivamente com Artemia enriquecida apresentaram sobrevivência (82%), peso (480±157mg) e comprimento (35,5±5,0mm) significativamente maiores (P&lt;0,05) que os juvenis alimentados com ração. Não houve diferença significativa (P&gt;0,05) no crescimento entre os juvenis alimentados com ração nos diferentes períodos, entretanto, um período maior de co-alimentação favoreceu a sobrevivência. Os resultados obtidos demonstram que os linguados alimentados exclusivamente com Artemia apresentam melhor performance do que aqueles alimentados com ração. Entretanto, o custo de produção quando a Artemia é substituída por ração aos 58 dias de vida é menor do que quando o desmame é realizado mais cedo ou quando os alevinos são alimentados apenas com Artemia.

Evaluation of DNase activity in seminal plasma and uptake of exogenous DNA by spermatozoa of the Brazilian flounder Paralichthys orbignyanus

Sperm mediated gene transfer (SMGT) has been successfully used in mammals, amphibians, birds, and some invertebrates. In fish, this methodology has failed or had poor efficiency for the production of transgenic specimens, presumably because the processes regulating the interaction between spermatozoa and exogenous DNA are not well understood. Therefore, the objective was to develop a SMGT protocol for the Brazilian flounder Paralichthys orbignyanus, with an emphasis on the role of seminal plasma DNase on exogenous DNA uptake by fish spermatozoa. In this study, there was strong DNase activity in the seminal plasma of P. orbignyanus; however, this DNase activity was decreased or eliminated by washing the spermatozoa with solutions containing EDTA (DNase activity was completely inhibited by 40 mM EDTA). Three washing solutions were tested, all of which maintained sperm quality. Moreover, it was determined that the no more than 50 ng of exogenous DNA/10 6 cells should be used for SMGT in fish. Finally, it was demonstrated that fish spermatozoa were capable of spontaneous uptake of exogenous DNA after elimination of DNase activity; this was confirmed by exogenous DNA amplification (PCR using sperm genomic DNA as a template) after DNase I treatment. We concluded that whereas DNase activity was an important obstacle for exogenous DNA uptake by fish spermatozoa; controlling this activity improved the efficiency of SMGT in fish.

Potential environmental and host gender influences on prevalence of Haemogregarina platessae (Adeleorina: Haemogregarinidae) and suspected Haemohormidium terraenovae (incertae sedis) in Brazilian flounder from the Patos Lagoon Estuary, Southern Brazil

Flounder, Paralichthys orbignyanus (Valenciennes), were captured in polluted and non-polluted sites within the Patos Lagoon Estuary, southern Brazil, over four seasons. Blood films showed a high prevalence of infection with a haemogregarine, or mixed parasitaemias of this and an organism resembling Haemohormidium terraenovae So, 1972. Haemogregarine gamont stages conformed to existing descriptions of Desseria platessae (Lebailly, 1904) Siddall, 1995 from flatfishes, but intraerythrocytic division of meronts was observed, leading to the recommendation for nomenclatural correction, placing the haemogregarine in the genus Haemogregarina (sensu lato) Danilewsky, 1885. Statistical analyses suggested that although sample sizes were small, infections with meront stages, immature and mature gamonts were all influenced by site, and possibly therefore, by pollution. Season also appeared to determine likelihood of infection with meronts and immature gamonts, but not mature gamonts, while adult fish gender apparently affected infection with immature and mature gamonts, but not meronts. The H. terraenovae-like organism exhibited unusual extracellular forms and did not match closely with the type description of H. terraenovae; precise identification was therefore difficult. Data analyses suggested that parasitism by this organism was influenced by site and fish gender, since females and males from non-polluted water were infected, but only females from the polluted site. Season was also important and significantly more adult fish of both sexes were infected with this parasite in the Brazilian summer and autumn, compared with winter and spring. Finally, these appeared to be the first observations of Haemogregarina platessae, and possibly H. terraenovae, from the southern hemisphere.

Hormone-induced ovulation, natural spawning and larviculture of Brazilian flounder Paralichthys orbignyanus (Valenciennes, 1839)

Mature Brazilian flounders Paralichthys orbignyanus were captured in coastal southern Brazil and their reproduction in captivity was studied. Brazilian flounder will spawn naturally in captivity when the water temperature is around 23 °C and 14 h of light is provided daily. Females were induced for ovulation and hand stripping using human chorionic gonadotropin, luteinizing hormone-releasing hormone analogue or carp pituitary extract. There was no need to inject males, as running milt was observed during the spawning season. Fertilization and hatching rates were above 80% independent of the hormone used. Notochord length at hatching was 2.18±0.07 mm for larvae hatching from naturally spawned eggs. Larvae were reared in salt water (30–35 g L−1) at 24 °C and under continuous illumination. Larviculture was with green water (Tetraselmis tetrathele 50 × 104 cells mL−1). Rotifers (10–20 ind mL−1) were offered as first food 3 days after hatching and gradually replaced by Artemia nauplii (0.5–10 ind mL−1). Larvae settled to the bottom 20 days after hatching and completed metamorphosis within a week after that. The total length for newly metamorphosed juveniles was 12.9±2.2 mm and the mean survival was 44.8%. The results demonstrate the feasibility of producing Brazilian flounder fingerlings for stock enhancement or grow-out purposes.

Cryopreservation of Brazilian flounder (Paralichthys orbignyanus) sperm

The Brazilian flounder, Paralichthys orbignyanus, is being considered for aquaculture due to its high demand and market price. Reproduction and larviculture studies have demonstrated the feasibility of massive fingerling production, and techniques that prolong life and increase gamete viability can assist in the culture development of this species. The aim of this study was to evaluate the efficiency of two different cryosolutions for cryopreservation of Brazilian flounder semen in order to improve broodstock management and consequently augment the potential for its culture. Two different cryosolutions were tested: a) glycerol–saline: glycerol solution (12% or 1.65 M) along a saline-based diluent (423 mM NaCl, 9 mM KCl, 9.25 mM CaCl2.2H2O, 22.92 mM MgCl2.6H2O, 25.5 mM MgSO4.7H2O and 2.15 mM NaHCO3; pH 8.2; osmolality 900 mOsmol/kg); and b) DMSO–sucrose: DMSO solution (10% or 1.40 M) along a sucrose-based diluent (110 mM Sucrose, 100 mM KHCO3 and 10 mM Tris-Cl; pH 8.2; osmolality 335 mOsmol/kg). Cryopreservation was made without equilibration time. First, 250 μl-straws were placed 6 cm above the surface of liquid nitrogen for 10 min, then they were maintained for 5 min on the surface of liquid nitrogen (1 cm) before being plunged into liquid nitrogen. The quality of cryopreserved sperm was assessed through the percentage of sperm motility and viability, fertilization capacity, hatching and larval viability. Motility was estimated with an arbitrary scale, ranging from 0 to 5. Spermatozoa viability was determined using a LIVE/DEAD® sperm viability kit. Motility of fresh sperm (3.5±0.2) was similar to frozen/thawed sperm with DMSO-sucrose (2.5±0.3) (P>0.05). On the other hand, the motility of frozen/thawed sperm with glycerol-saline (1.3±0.4) was lower than the other two treatments (P<0.05). No difference was found in the percentage of live spermatozoa post-thawed between DMSO–sucrose and glycerol–saline solutions (P<0.05). However, fresh sperm had a higher percentage of live spermatozoa than post-thawed sperm with glycerol-saline (P<0.05). Sperm motility was positively correlated with the percentage of live spermatozoa (Adjusted R2=0.61, n=13). No difference was found for fertilization and hatching rates and larvae viability among the three treatments (P>0.05). This is the first report on successful cryopreservation of Brazilian flounder sperm. This procedure should improve broodstock management techniques for this species and consequently augment the potential for its culture.