22 research outputs found
Sobrevivência e crescimento de juvenis de linguado paralichthys orbignyanus criados em diferentes temperaturas
O linguado Paralichthys orbignyanus é um importante recurso pesqueiro que está despertando o interesse de sua produção em
cativeiro. Este trabalho avaliou o efeito da temperatura sobre juvenis do linguado. Juvenis (32,3 ± 1,6 mg) foram mantidos nas
temperaturas de 17, 20, 23 e 26°C, todas com duas repetições. A cada duas semanas, durante 56 dias, todos os peixes foram
medidos e pesados. O tratamento estatístico dos resultados foi feito por Análise de Variância (uma via) seguida do Teste de
Tukey, com 95% de significância. A sobrevivência foi de 100% em todos os tratamentos, indicando que logo após a
metamorfose o linguado já é euritérmico. A taxa de crescimento específico diário foi de 5,25 ± 0,06% (23°C), 4,87 ± 0,23%
(26°C), 4,66 ± 0,21% (20°C) e 4,07 ± 0,14% (17°C), havendo diferença significativa apenas entre 23 e 17°C (P<0,05). Foi
observada diferença significativa apenas no peso final dos linguados criados a 23°C (608,8 ± 76,3 mg) e 17°C (318,7 ± 22,1
mg) (P<0,05). De acordo com os resultados obtidos neste trabalho, sugere-se que o berçário de P. orbignyanus seja realizado
entre 20 e 26°C.The Brazilian flounder Paralichthys orbignyanus is an important fisheries resource and it is being considered for aquaculture.
This study evaluated the effect of temperature on juvenile flounder. Fish (32.3 ± 1.6 mg) were reared at 17, 20, 23 and 26°C,
with duplicate tanks for each temperature. Every two weeks, during 56 days, all fish were measured and weighed. Statistical
treatment of results was done by One-Way ANOVA followed by the Tukey’s Test, with 95% significance. Survival was 100% in
all treatments, suggesting that Brazilian flounder is eurythermic soon after completing metamorphosis. The daily specific growth
rate was 5.25 ± 0.06% (23°C), 4.87 ± 0.23% (26°C), 4.66 ± 0.21% (20°C) and 4.07 ± 0.14% (17°C) with significant difference
only between 23 and 17°C (P<0.05). Significant difference was observed only in the final weight of flounders reared at 23°C
(608.8 ± 76.3 mg) and 17°C (318.7 ± 22.1 mg) (P<0.05). According to the results obtained in this study, it is suggested that
juvenile P. orbignyanus should be reared in temperatures between 20 and 26°C
Survival and growth of juvenile brazilian flounder paralichthys orbignyanus reared at different temperatures
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Previous issue date: 2012O linguado Paralichthys orbignyanus é um importante recurso pesqueiro que está despertando o interesse de sua produção em
cativeiro. Este trabalho avaliou o efeito da temperatura sobre juvenis do linguado. Juvenis (32,3 ± 1,6 mg) foram mantidos nas
temperaturas de 17, 20, 23 e 26°C, todas com duas repetições. A cada duas semanas, durante 56 dias, todos os peixes foram
medidos e pesados. O tratamento estatístico dos resultados foi feito por Análise de Variância (uma via) seguida do Teste de
Tukey, com 95% de significância. A sobrevivência foi de 100% em todos os tratamentos, indicando que logo após a
metamorfose o linguado já é euritérmico. A taxa de crescimento específico diário foi de 5,25 ± 0,06% (23°C), 4,87 ± 0,23%
(26°C), 4,66 ± 0,21% (20°C) e 4,07 ± 0,14% (17°C), havendo diferença significativa apenas entre 23 e 17°C (P<0,05). Foi
observada diferença significativa apenas no peso final dos linguados criados a 23°C (608,8 ± 76,3 mg) e 17°C (318,7 ± 22,1
mg) (P<0,05). De acordo com os resultados obtidos neste trabalho, sugere-se que o berçário de P. orbignyanus seja realizado
entre 20 e 26°C.The Brazilian flounder Paralichthys orbignyanus is an important fisheries resource and it is being considered for aquaculture.
This study evaluated the effect of temperature on juvenile flounder. Fish (32.3 ± 1.6 mg) were reared at 17, 20, 23 and 26°C,
with duplicate tanks for each temperature. Every two weeks, during 56 days, all fish were measured and weighed. Statistical
treatment of results was done by One-Way ANOVA followed by the Tukey’s Test, with 95% significance. Survival was 100% in
all treatments, suggesting that Brazilian flounder is eurythermic soon after completing metamorphosis. The daily specific growth
rate was 5.25 ± 0.06% (23°C), 4.87 ± 0.23% (26°C), 4.66 ± 0.21% (20°C) and 4.07 ± 0.14% (17°C) with significant difference
only between 23 and 17°C (P<0.05). Significant difference was observed only in the final weight of flounders reared at 23°C
(608.8 ± 76.3 mg) and 17°C (318.7 ± 22.1 mg) (P<0.05). According to the results obtained in this study, it is suggested that
juvenile P. orbignyanus should be reared in temperatures between 20 and 26°C
Physiological responses of cobia rachycentron canadum following exposure to low water and air exposure stress challenges
Prevention is the most viable disease management strategy in aquaculture, and prevention is primarily
driven by strategies to avoid or minimize the effects of stress. Unfortunately, there is little information
available regarding the stress physiology of emerging aquaculture species or appropriate experimental
stressing protocols for these fishes, and thus very little context in which to evaluate mitigation strategies.
Accordingly, the stress response of cobia was evaluated following exposure to 2 experimental stressors: low
water and air exposure. Juveniles were exposed to air for 1 min (AIR EXPOSURE), held for 15 min in water
lowered to the fish's lateral midline (LOW WATER), or unchallenged (CONTROL) prior to the collection of
blood samples at 0 (pre-challenge), 0.5, 1, 2, 6, 12, 24, 48, and 72 h post-challenge. Both stressors elicited
classical haematological changes indicative of the generalized stress response, however, the magnitude of the
response was consistently greater in the AIR EXPOSURE group. Plasma cortisol, glucose, and lactate
concentrations increased rapidly in the AIR EXPOSURE and LOW WATER groups, peaking within 1 h of
challenge. Cortisol returned to basal levels rapidly, whereas glucose and lactate remained elevated for a longer
period of time. Regardless of the stressor used, fish recovered within 12 h of the challenge. The primary and
secondary responses of juvenile cobia challenged with low water and air exposure appear to respond in a
similar fashion to other species exposed to these experimental stressors. Both low water and air exposure are
suitable experimental stressors for use in cobia based on their ability to induce a classical stress response and
ease of implementation
Micobacteriose por Mycobacterium marinum em “linguado” Poaralichthys orbignyanus e em “barber goby” Elacatinus figaro: diagnóstico histopatológico e imuno-histoquímico
Mycobacteriosis affects various species of fish, including those cultured with commercial purposes. It is a chronic systemic with granuloma forming disease known as fish mycobacteriosis. In the last few years the interest of fish culture has been increasing due to the reduction of the natural fish stocks. However the intensification of fish culture has collaborated to the development of diseases such as mycobacteriosis, causing losses due to the chronic characteristics and difficult diagnosis. This study is to report two cases of mycobacteriosis observed at "Laboratório de Piscicultura Estuarina e Marinha of the Universidade Federal do Rio Grande (FURG)", one for Brazilian flounder Paralichthys orbignyanus and another for barber goby Elacatinus figaro. The Fite-Faraco staining protocol was used. Membranes of mycobacterial cells contain a waxy substance composed of mycolic acids. These are ß-hydroxy carboxylic acids with chain lengths of up to 90 carbon atoms. The property of acid fastness is related to the carbon chain length of the mycolic acid found in any particular species. The fish mycobacterium is much less acid and alcohol fast than the tubercle bacillus and the classic Ziehl-Neelsen Staining Protocol may give false results. The presence of mycobacterial antigen lesions was studied by immunohistological methods using monoclonal antibodies to Mycobacterium marinum. Humans may be infected by these bacteria and develop cutaneous granuloma. In this paper the necessity is stressed for a correct diagnosis of the disease, contributing to the prevention of its establishment in aquatic facilities, and thus, preserving cultured fish as well as human beings from infection.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
Effects of light intensity on growth of juvenile Brazilian flounder paralichthys orbignyanus
Most fishes require a minimum threshold light intensity to be able to develop and grow. The aim of
this study was to evaluate the effect of light intensity on growth of juvenile Brazilian flounder
Paralichthys orbignyanus. Juvenile flounder (1.55 ± 0.03 g) were randomly distributed into twelve
50 L tanks (75 fish per tank). Light intensities tested were 5 (5 ± 1 lux), 180 (176 ± 6 lux), 700 (712 ±
29 lux) and 2000 lux (1,998 ± 64 lux), all in triplicate. Throughout 42 days, fish were fed a
commercial feed until satiation. Salinity was maintained at 32 g L-1, temperature at 23 °C, dissolved
oxygen at 6.6 mg L-1, pH at 7.8 and un-ionized ammonia at 0.01 mg L-1 NH3-N. At the end of the
experiment, juveniles reared at 5 and 180 lux reached respectively 10.1 ± 0.3 and 9.44 ± 0.3 g, their
weight was higher than those reared at 700 lux (8.45 ± 0.3 g) and 2000 lux (8.44 ± 0.3 g) (P<0.05).
Specific growth rate was higher at 5 lux (4.6 ± 0.2%), compared to 700 lux (4.0 ± 0.1%) and 2000 lux
(4.0 ± 0.1%) (P<0.05), while fish reared at 180 lux (4.3 ± 0.1%) did not differ from the other
treatments (P>0.05). Survival was 100% at all light intensities tested. It was observed that juvenile
Brazilian flounder growth is affected by light intensity, and according to the results obtained, they
should be reared at light intensities ranging between 5 and 180 lux.A maioria dos peixes necessita de um ambiente com uma intensidade luminosa mínima para o seu
desenvolvimento e crescimento. O objetivo do presente estudo foi avaliar o efeito da intensidade
luminosa sobre o crescimento de juvenis do linguado Paralichthys orbignyanus. Juvenis de 1,55 ±
0,03 g foram distribuídos aleatoriamente em 12 tanques de 50 L (75 peixes por tanque). As
intensidades luminosas testadas foram 5 (5 ± 1 lux), 180 (176 ± 6 lux), 700 (712 ± 29 lux) e 2.000 lux
(1.998 ± 64 lux), todas em três repetições. Durante 42 dias, os peixes foram alimentados com ração
comercial até à saciedade. A salinidade foi mantida em 32 g L-1, a temperatura em 23 °C, o oxigênio
dissolvido em 6,6 mg L-1, o pH em 7,8 e a amônia não ionizada em 0,01 mg L-1 NH3-N. Ao final do
experimento, os juvenis mantidos sob 5 e 180 lux apresentaram respectivamente 10,1 ± 0,3 e 9,44 ±
0,3 g, pesos superiores aos mantidos sob 700 lux (8,45 ± 0,3 g) e 2.000 lux (8,44 ± 0,3 g) (P<0,05). A
taxa de crescimento específico diário foi maior sob 5 lux (4,6 ± 0,2%), quando comparada às obtidas
sob 700 lux (4,0 ± 0,1%) e 2.000 lux (4,0 ± 0,1%) (P<0,05), enquanto que a obtida sob 180 lux (4,3 ±
0,1%) não diferiu de nenhuma (P>0,05). A sobrevivência foi de 100% em todos os tratamentos. De
acordo com os resultados obtidos, juvenis de linguado devem ser criados entre 5 e 180 lux
Efeito da densidade de estocagem no cultivo de tainha, Mugil platanus (Günther, 1880) em laboratório
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Previous issue date: 2001The effect of stocking density on production of Mugil platanus fingerlings in
laboratory was analyzed. Five stocking densities were evaluated: 1, 3, 5, 10 and 15 mullet/L.
After 28 days, the highest growth rate was reported for animals reared at the lowest stocking
density (1 mullet/L). Survival rate and water quality were also higher at the lowest stocking
density. Although more fingerlings were produced at 10 mullet/L, greater number of
animals decreased the water quality, which was reflected in their reduced growth and
survival rates. M. platanus fingerlings should be reared in commercial production at
intermediate stocking densities (3-5 mullet/L) but higher water exchange rates are
recommended for lower ammonia concentration.Estudou-se o efeito da densidade de estocagem sobre a
produção de alevinos de Mugil platanus em laboratório. Foram testadas cinco densidades de
estocagem em duplicata: 1, 3, 5, 10 e 15 tainhas/L. Os peixes foram alimentados duas vezes
ao dia, sendo oferecido alimento na proporção de 10% do peso vivo de cada tanque. O
melhor crescimento foi observado para os animais cultivados na menor densidade de
estocagem (1 alevino/L). Observaram-se neste tratamento a melhor qualidade de água e a
maior sobrevivência. Por outro lado, o maior número de animais foi produzido na
densidade de 10 alevinos/L; entretanto, isto foi obtido às custas de uma menor qualidade da
água, que se refletiu em uma redução no crescimento e na sobrevivência. No caso de
produção comercial, os alevinos de M. platanus poderiam ser cultivados em uma densidade
de estocagem entre 3 e 5 alevinos/L; contudo, a taxa de troca de água deveria ser mais
elevada, para manter a concentração de amônia mais baixa do que aquela observada neste
trabalh
Efeito da intensidade luminosa sobre o crescimento de juvenis do linguado paralichthys orbignyanus
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Previous issue date: 2015Most fishes require a minimum threshold light intensity to be able to develop and grow. The aim of
this study was to evaluate the effect of light intensity on growth of juvenile Brazilian flounder
Paralichthys orbignyanus. Juvenile flounder (1.55 ± 0.03 g) were randomly distributed into twelve
50 L tanks (75 fish per tank). Light intensities tested were 5 (5 ± 1 lux), 180 (176 ± 6 lux), 700 (712 ±
29 lux) and 2000 lux (1,998 ± 64 lux), all in triplicate. Throughout 42 days, fish were fed a
commercial feed until satiation. Salinity was maintained at 32 g L-1, temperature at 23 °C, dissolved
oxygen at 6.6 mg L-1, pH at 7.8 and un-ionized ammonia at 0.01 mg L-1 NH3-N. At the end of the
experiment, juveniles reared at 5 and 180 lux reached respectively 10.1 ± 0.3 and 9.44 ± 0.3 g, their
weight was higher than those reared at 700 lux (8.45 ± 0.3 g) and 2000 lux (8.44 ± 0.3 g) (P<0.05).
Specific growth rate was higher at 5 lux (4.6 ± 0.2%), compared to 700 lux (4.0 ± 0.1%) and 2000 lux
(4.0 ± 0.1%) (P<0.05), while fish reared at 180 lux (4.3 ± 0.1%) did not differ from the other
treatments (P>0.05). Survival was 100% at all light intensities tested. It was observed that juvenile
Brazilian flounder growth is affected by light intensity, and according to the results obtained, they
should be reared at light intensities ranging between 5 and 180 lux.A maioria dos peixes necessita de um ambiente com uma intensidade luminosa mínima para o seu
desenvolvimento e crescimento. O objetivo do presente estudo foi avaliar o efeito da intensidade
luminosa sobre o crescimento de juvenis do linguado Paralichthys orbignyanus. Juvenis de 1,55 ±
0,03 g foram distribuídos aleatoriamente em 12 tanques de 50 L (75 peixes por tanque). As
intensidades luminosas testadas foram 5 (5 ± 1 lux), 180 (176 ± 6 lux), 700 (712 ± 29 lux) e 2.000 lux
(1.998 ± 64 lux), todas em três repetições. Durante 42 dias, os peixes foram alimentados com ração
comercial até à saciedade. A salinidade foi mantida em 32 g L-1, a temperatura em 23 °C, o oxigênio
dissolvido em 6,6 mg L-1, o pH em 7,8 e a amônia não ionizada em 0,01 mg L-1 NH3-N. Ao final do
experimento, os juvenis mantidos sob 5 e 180 lux apresentaram respectivamente 10,1 ± 0,3 e 9,44 ±
0,3 g, pesos superiores aos mantidos sob 700 lux (8,45 ± 0,3 g) e 2.000 lux (8,44 ± 0,3 g) (P<0,05). A
taxa de crescimento específico diário foi maior sob 5 lux (4,6 ± 0,2%), quando comparada às obtidas
sob 700 lux (4,0 ± 0,1%) e 2.000 lux (4,0 ± 0,1%) (P<0,05), enquanto que a obtida sob 180 lux (4,3 ±
0,1%) não diferiu de nenhuma (P>0,05). A sobrevivência foi de 100% em todos os tratamentos. De
acordo com os resultados obtidos, juvenis de linguado devem ser criados entre 5 e 180 lux
Acclimation of juvenile mugil iiza valenciennes, 1836 (mugiliformes: mugilidae) to different environmental salinities
Survival and physiological parameters associated with metabolism and osmoregulation were evaluated in juveniles of the
Lebranche mullet Mugil liza acclimated to different water salinities (5, 10, 20, 30, and 40‰) for 15 days. Room temperature
(25°C) and photoperiod (12L:12D) were fixed. Fish were fed twice-a-day with commercial diet (28% crude protein) until
satiation. After acclimation, whole body oxygen consumption was measured and fish were euthanized and sampled for
blood, gills, and liver. Whole body oxygen consumption and plasma osmolality did not change in the range of salinities
tested. The isosmotic point was estimated as 412.7 mOsmol kg-1 (13.5‰). Gill Na+
,K+-ATPase activity tended to be lower at
20 and 30‰, while liver glycogen content was significantly higher at 20‰ than at 5 and 40‰. These results indicate that
juvenile M. liza is able to acclimate for a short-period of time (15 days) to a wide range of salinities (5-40‰). This condition
is achieved through adjustments in gill Na+
,K+-ATPase activity and carbohydrate metabolism to regulate plasma osmolality
and aerobic/energy metabolism. Therefore, our findings support the idea of catching juveniles M. liza in sea water and rear
them in estuarine and marine waters.A sobrevivência e parâmetros fisiológicos associados ao metabolismo e a osmorregulação foram avaliados em juvenis da
tainha Mugil liza aclimatada à diferentes salinidades (5, 10, 20, 30 e 40‰) por 15 dias. Foram fixadas a temperatura (25°C)
e o fotoperíodo (12L:12D) da sala onde os experimentos foram realizados. Os peixes foram alimentados duas vezes ao dia
com ração comercial (28% de proteína bruta) até a saciedade. Após aclimatação, foi medido o consumo corporal de oxigênio
e os peixes foram eutanasiados e foram coletadas amostras de sangue, brânquias e fígado. O consumo corporal de oxigênio
e a osmolalidade plasmática não variaram na faixa de salinidade testada. O ponto isosmótico foi estimado em 412,7 mOsmol
kg-1 (13,5‰). A atividade da Na+
,K+-ATPase branquial tendeu a ser menor em 20 e 30‰, enquanto o conteúdo de glicogênio
hepático foi significativamente maior em 20‰ do que em 5 e 40‰. Estes resultados indicam que o juvenil de M. liza é capaz
de se aclimatar a uma ampla faixa de salinidade (5-40‰) por um curto período de tempo (15 dias). Esta condição é atingida
através de ajustes na atividade da Na+
,K+-ATPase branquial e no metabolismo de carboidratos para regular a osmolalidade
plasmática e o metabolismo aeróbico/energético. Portanto, nossos achados suportam a ideia de que é possível capturar
juvenis da tainha M. liza em água do mar e cultivá-los em águas estuarinas e marinhas
Effect of stocking density on laboratory rearing of mullet fingerlings, Mugil platanus (Günther, 1880)
The effect of stocking density on production of Mugil platanus fingerlings in
laboratory was analyzed. Five stocking densities were evaluated: 1, 3, 5, 10 and 15 mullet/L.
After 28 days, the highest growth rate was reported for animals reared at the lowest stocking
density (1 mullet/L). Survival rate and water quality were also higher at the lowest stocking
density. Although more fingerlings were produced at 10 mullet/L, greater number of
animals decreased the water quality, which was reflected in their reduced growth and
survival rates. M. platanus fingerlings should be reared in commercial production at
intermediate stocking densities (3-5 mullet/L) but higher water exchange rates are
recommended for lower ammonia concentration.Estudou-se o efeito da densidade de estocagem sobre a
produção de alevinos de Mugil platanus em laboratório. Foram testadas cinco densidades de
estocagem em duplicata: 1, 3, 5, 10 e 15 tainhas/L. Os peixes foram alimentados duas vezes
ao dia, sendo oferecido alimento na proporção de 10% do peso vivo de cada tanque. O
melhor crescimento foi observado para os animais cultivados na menor densidade de
estocagem (1 alevino/L). Observaram-se neste tratamento a melhor qualidade de água e a
maior sobrevivência. Por outro lado, o maior número de animais foi produzido na
densidade de 10 alevinos/L; entretanto, isto foi obtido às custas de uma menor qualidade da
água, que se refletiu em uma redução no crescimento e na sobrevivência. No caso de
produção comercial, os alevinos de M. platanus poderiam ser cultivados em uma densidade
de estocagem entre 3 e 5 alevinos/L; contudo, a taxa de troca de água deveria ser mais
elevada, para manter a concentração de amônia mais baixa do que aquela observada neste
trabalh
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/106 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