Metaplasia in swim bladder epithelium of the endangered annual fish Austrolebias nigrofasciatus (Cyprinodontiformes: Rivulidae) results in inadequate swimming and delayed growth

Laboratory breeding of annual fish is often impaired when fish fail to inflate the swim bladder after hatching. These fish, which are known as belly-sliders, cannot swim in the water column, moving mainly on the bottom of water. Therefore, we wanted to understand the factors underlying failed inflation of swim bladder in the annual fish Austrolebias nigrofasciatus and determine the implications of this condition on the growth of juveniles. To identify how the initial filling of the gaseous vesicle is compromised, and to determine the implications of this condition on juvenile growth, we analysed the histology of the swim bladder of both normal swimming fish and belly-sliders during their initial growth phase (first month of life). In addition to slower growth rate compared with fish swimming normally, we found that belly-sliders have metaplasia characterized by epithelium peeling of the swim bladder and the presence of haemorrhage. Based on our findings, it can be concluded that metaplasia of the swim bladder is recurrent in annual fish bred in the laboratory, which explains the large number of unviable larvae. However, its causes remain unknown.(AU)

A criação de peixes anuais é frequentemente comprometida pela ocorrência de peixes que não inflam a vesícula gasosa após a eclosão. Estes peixes não têm capacidade de se manter e nadar na coluna d'água e se locomovem no fundo da água, por isso são chamados belly-sliders. Portanto, objetivamos entender os fatores subjacentes à inflação falhada da bexiga natatória no peixe anual Austrolebias nigrofasciatus e determinar as implicações dessa condição no crescimento de juvenis. Para identificar de que forma o enchimento inicial da vesícula gasosa é comprometido, e determinar as implicações desta condição no crescimento dos juvenis, analisamos histologicamente a vesícula gasosa de peixes com natação normal e de belly-sliders durante o crescimento inicial (primeiro mês de vida). Verificamos que os belly-sliders apresentam metaplasia com descamação do epitélio da vesícula gasosa e presença de hemorragia, além de apresentar crescimento mais lento em relação aos peixes com natação normal. Concluímos que a incidência desta patologia é um problema recorrente e de grande relevância para a manutenção de peixes anuais em laboratório, sendo responsável por uma grande quantidade de juvenis inviáveis, no entanto suas causas permanecem desconhecidas.(AU)

Metaplasia in swim bladder epithelium of the endangered annual fish Austrolebias nigrofasciatus (Cyprinodontiformes: Rivulidae) results in inadequate swimming and delayed growth

Laboratory breeding of annual fish is often impaired when fish fail to inflate the swim bladder after hatching. These fish, which are known as belly-sliders, cannot swim in the water column, moving mainly on the bottom of water. Therefore, we wanted to understand the factors underlying failed inflation of swim bladder in the annual fish Austrolebias nigrofasciatus and determine the implications of this condition on the growth of juveniles. To identify how the initial filling of the gaseous vesicle is compromised, and to determine the implications of this condition on juvenile growth, we analysed the histology of the swim bladder of both normal swimming fish and belly-sliders during their initial growth phase (first month of life). In addition to slower growth rate compared with fish swimming normally, we found that belly-sliders have metaplasia characterized by epithelium peeling of the swim bladder and the presence of haemorrhage. Based on our findings, it can be concluded that metaplasia of the swim bladder is recurrent in annual fish bred in the laboratory, which explains the large number of unviable larvae. However, its causes remain unknown.(AU)

A criação de peixes anuais é frequentemente comprometida pela ocorrência de peixes que não inflam a vesícula gasosa após a eclosão. Estes peixes não têm capacidade de se manter e nadar na coluna d'água e se locomovem no fundo da água, por isso são chamados belly-sliders. Portanto, objetivamos entender os fatores subjacentes à inflação falhada da bexiga natatória no peixe anual Austrolebias nigrofasciatus e determinar as implicações dessa condição no crescimento de juvenis. Para identificar de que forma o enchimento inicial da vesícula gasosa é comprometido, e determinar as implicações desta condição no crescimento dos juvenis, analisamos histologicamente a vesícula gasosa de peixes com natação normal e de belly-sliders durante o crescimento inicial (primeiro mês de vida). Verificamos que os belly-sliders apresentam metaplasia com descamação do epitélio da vesícula gasosa e presença de hemorragia, além de apresentar crescimento mais lento em relação aos peixes com natação normal. Concluímos que a incidência desta patologia é um problema recorrente e de grande relevância para a manutenção de peixes anuais em laboratório, sendo responsável por uma grande quantidade de juvenis inviáveis, no entanto suas causas permanecem desconhecidas.(AU)

Use of exogenous enzymes in diets for juvenile pompano Trachinotus marginatus: growth and liver and intestine morphophysiology / Uso de enzimas exógenas em dietas para juvenis de pampo Trachinotus marginatus: crescimento e morfofiologia do fígado e intestino

This study investigated the use of exogenous enzymes in diets of juvenile pompano Trachinotus marginatus. Six diets (43% protein, 8% lipid), containing 0 (TC), 25 (T25), 50 (T50), 100 (T100), 250 (T250), and 500 (T500) mg kg-1 of multiple enzymes Rovabio® MAX AP were produced. The effects on growth performance, body composition, liver glycogen, triglyceride levels, and intestinal and hepatic morphological alterations were assessed. The results showed significant differences (p < 0.05) in growth performance among fish fed diets T100, T250, and T500, with high liver triglyceride accumulation and changes in morphology in the fish fed diets T250 and T500. The calcium concentration in the bones showed a significant difference (P < 0.05) only in fish fed diets T50, T100, and T250 in relation to control. However, there were no significant differences in body composition, intestinal morphology, or liver glycogen concentration. These results suggest that 100 mg enzyme per kg diet was the optimal level of inclusion for juvenile pompano, favoring improved growth performance and calcium concentration in the bones without significant effects on liver triglyceride levels.

Este estudo investigou o uso de enzimas exógenas em dietas para juvenis de pampo prateado Trachinotus marginatus. Foram preparadas seis dietas (43% de proteína, 8% de lipídio), contendo 0 (TC), 25 (T25), 50 (T50), 100 (T100), 250 (T250) e 500 (T500) mg kg-1 do complexo enzimático Rovabio® Max AP. Avaliou-se os efeitos sobre o crescimento, composição de carcaça, níveis de glicogênio e triglicerídeo no fígado e possíveis alterações na morfologia do intestino e fígado. Os resultados mostraram diferença significativa (p 0,05) na composição de carcaça, morfologia do intestino e concentração de glicogênio no fígado. Esses resultados indicam que o uso de 100 mg kg-1 de enzimas na dieta mostrou ser o melhor nível de inclusão para juvenis de pampo prateado, favorecendo o crescimento e a concentração de cálcio nos ossos. Sem efeitos significativos sobre os níveis de triglicerídeos no fígado.

Use of exogenous enzymes in diets for juvenile pompano Trachinotus marginatus: growth and liver and intestine morphophysiology / Uso de enzimas exógenas em dietas para juvenis de pampo Trachinotus marginatus: crescimento e morfofiologia do fígado e intestino

This study investigated the use of exogenous enzymes in diets of juvenile pompano Trachinotus marginatus. Six diets (43% protein, 8% lipid), containing 0 (TC), 25 (T25), 50 (T50), 100 (T100), 250 (T250), and 500 (T500) mg kg-1 of multiple enzymes Rovabio® MAX AP were produced. The effects on growth performance, body composition, liver glycogen, triglyceride levels, and intestinal and hepatic morphological alterations were assessed. The results showed significant differences (p < 0.05) in growth performance among fish fed diets T100, T250, and T500, with high liver triglyceride accumulation and changes in morphology in the fish fed diets T250 and T500. The calcium concentration in the bones showed a significant difference (P < 0.05) only in fish fed diets T50, T100, and T250 in relation to control. However, there were no significant differences in body composition, intestinal morphology, or liver glycogen concentration. These results suggest that 100 mg enzyme per kg diet was the optimal level of inclusion for juvenile pompano, favoring improved growth performance and calcium concentration in the bones without significant effects on liver triglyceride levels.(AU)

Este estudo investigou o uso de enzimas exógenas em dietas para juvenis de pampo prateado Trachinotus marginatus. Foram preparadas seis dietas (43% de proteína, 8% de lipídio), contendo 0 (TC), 25 (T25), 50 (T50), 100 (T100), 250 (T250) e 500 (T500) mg kg-1 do complexo enzimático Rovabio® Max AP. Avaliou-se os efeitos sobre o crescimento, composição de carcaça, níveis de glicogênio e triglicerídeo no fígado e possíveis alterações na morfologia do intestino e fígado. Os resultados mostraram diferença significativa (p < 0,05) no desempenho de crescimento dos peixes dos tratamentos T100, T250 e T500, com grande concentração de triglicerídeos e alteração na morfologia do fígado nos peixes dos tratamentos T250 e T500. A concentração de cálcio nos ossos também teve um aumento significativo (p < 0,05) nos peixes dos tratamentos T50, T100 e T250 em relação ao controle. Entretanto, não houve diferença significativa (p > 0,05) na composição de carcaça, morfologia do intestino e concentração de glicogênio no fígado. Esses resultados indicam que o uso de 100 mg kg-1 de enzimas na dieta mostrou ser o melhor nível de inclusão para juvenis de pampo prateado, favorecendo o crescimento e a concentração de cálcio nos ossos. Sem efeitos significativos sobre os níveis de triglicerídeos no fígado.(AU)

Arthrospira platensis filtrada como alimento complementario de juveniles del camarón blanco: efectos sobre crecimiento y sistema inmune / Filtered Arthrospira platensis as a food suplement for juvenile shrimp Litopenaeus vannamei: effects on growth and immune system

De forma general, las microalgas son fuente de alimento indispensable durante las primeras fases de desarrollo de los camarones marinos. Algunas microalgas, como la Arthrospira platensis, son ricas en substancias antioxidantes, y tienen la capacidad de retirar compuestos tóxicos del agua en los sistemas de producción acuícola. De este modo, constituimos un experimento con dos tratamientos triplicados, donde se evaluó la aplicación de biomasa filtrada de microalga A. platensis como suplemento alimenticio para camarón blanco del Pacífico, Litopenaeus vannamei. Se utilizó un sistema de cultivo estático de seis unidades, con volumen útil de 250 litros de agua marina (30 ppt), donde se sembraron 300 camarones m-2 con peso inicial de 0,7±0,2 g. Al final del experimento (42 días) se evaluaron parámetros inmunológicos y de desempeño zootécnico. Los camarones alimentados con A. platensis como como suplemento fueron signicativamente mayores que los camarones del tratamiento control y no presentaron diferencias en la supervivencia. Igualmente, se obtuvieron mejores resultados en los parámetros inmunológicos del tratamiento con inclusión de microalga. De esta forma, al suministrar la microalga como alimento suplementario al camarón L. vannamei, crecimiento y sistema inmunológico se vieron favorecidos.(AU)

Microalgae is an important food source during the early stages of marine shrimps. Some microalgae such as Arthrospira platensis, are rich in antioxidant substances and also have the capacity to remove toxics compounds from the water in aquaculture systems. The trial consisted in two treatements by triplicate, where the inclusion of filtered microalgae A. platensis as feed supplementation during production of juvenile Litopenaeus vannamei, was assessed. The experimental desing was based on a static system with six 250-L tanks with marine wáter (30 PSU), stocked 105 shirmps (300 shrimp m-2) with an average wheight of 0,7 ±0,2 g. At the end of the fed trial (42 days), the zootechnical and immunological parameters of shrimps were evaluated. Significatives differences among the treatments were found for both parameters. Shrimps that received supplementation of microalgae A. platensis showed higher growth and better response of the immune system. Thus, these results allow to conclude that the supplementation of filtered microalgae A. platensis improve growth and immunological parameters of white shrimp L. vannamei.(AU)

Micobacteriose em camarão branco do pacífico, Litopenaeus vannamei / Mycobacteriosis white shrimp pacific Litopenaeus vannamei

A infecção por Mycobacterium spp. tem sido constatada em diversos vertebrados, ocasionando doenças em humanos e animais. As espécies responsáveis pela ocorrência de micobacteriose em peixes, a saber, Mycobacterium marinum, M. fortuitum e M. chelonae, também são potencialmente infecciosas para os camarões peneídeos. A micobacteriose que afeta crustáceos corresponde a uma enfermidade sistêmica, granulomatosa, possuindo como agente etiológico bacilos Gram positivos ácido-álcool resistentes. Relata-se neste trabalho a ocorrência de micobacteriose em camarões da espécie Litopenaeus vannamei, sendo identificada a bactéria M. marinum nas amostras teciduais analisadas. Durante a manutenção de juvenis da espécie foram observadas lesões enegrecidas no sexto segmento abdominal de 20 espécimes. A partir das técnicas de Fite-Faraco e Fluorescence In Situ Hybridization (FISH) foi identificado o patógeno, representando uma doença bacteriana com potencial zootécnico que ocorre em ambientes aquáticos, acarretando riscos de contaminação tópica em pessoas envolvidas na manipulação de camarões.(AU)

The Mycobacterium spp. infection they have been documented in many vertebrates, causing known diseases in man and animals. The species responsible for the occurrence of mycobacteriosis in fish, Mycobacterium marinum, M. fortuitum and M. chelonae, are also potentially infectious for penaeid shrimp. The mycobacterial disease that affects shellfish corresponds to a systemic disease, granulomatous, having as an etiological agent Gram-positive bacilli resistant acid-alcohol. We report the occurrence of mycobacteriosis in shrimps of the species Litopenaeus vannamei, and identified the species M. marinum in tissue samples analyzed. During the maintenance of juvenile of the species, blackish lesions were observed in the sixth abdominal segment in 20 specimens. From techniques Fite-Faraco and hybridization in situ with fluorescence (FISH), has identified the pathogen in the analyzed tissue was observed, representing a bacterial disease of aquatic environments with zoonotic potential, causing risks of topical contamination on people involved in handling shrimp.(AU)

Micobacteriose em camarão branco do pacífico, Litopenaeus vannamei / Mycobacteriosis white shrimp pacific Litopenaeus vannamei

A infecção por Mycobacterium spp. tem sido constatada em diversos vertebrados, ocasionando doenças em humanos e animais. As espécies responsáveis pela ocorrência de micobacteriose em peixes, a saber, Mycobacterium marinum, M. fortuitum e M. chelonae, também são potencialmente infecciosas para os camarões peneídeos. A micobacteriose que afeta crustáceos corresponde a uma enfermidade sistêmica, granulomatosa, possuindo como agente etiológico bacilos Gram positivos ácido-álcool resistentes. Relata-se neste trabalho a ocorrência de micobacteriose em camarões da espécie Litopenaeus vannamei, sendo identificada a bactéria M. marinum nas amostras teciduais analisadas. Durante a manutenção de juvenis da espécie foram observadas lesões enegrecidas no sexto segmento abdominal de 20 espécimes. A partir das técnicas de Fite-Faraco e Fluorescence In Situ Hybridization (FISH) foi identificado o patógeno, representando uma doença bacteriana com potencial zootécnico que ocorre em ambientes aquáticos, acarretando riscos de contaminação tópica em pessoas envolvidas na manipulação de camarões.

The Mycobacterium spp. infection they have been documented in many vertebrates, causing known diseases in man and animals. The species responsible for the occurrence of mycobacteriosis in fish, Mycobacterium marinum, M. fortuitum and M. chelonae, are also potentially infectious for penaeid shrimp. The mycobacterial disease that affects shellfish corresponds to a systemic disease, granulomatous, having as an etiological agent Gram-positive bacilli resistant acid-alcohol. We report the occurrence of mycobacteriosis in shrimps of the species Litopenaeus vannamei, and identified the species M. marinum in tissue samples analyzed. During the maintenance of juvenile of the species, blackish lesions were observed in the sixth abdominal segment in 20 specimens. From techniques Fite-Faraco and hybridization in situ with fluorescence (FISH), has identified the pathogen in the analyzed tissue was observed, representing a bacterial disease of aquatic environments with zoonotic potential, causing risks of topical contamination on people involved in handling shrimp.

Arthrospira platensis filtrada como alimento complementario de juveniles del camarón blanco: efectos sobre crecimiento y sistema inmune / Filtered Arthrospira platensis as a food suplement for juvenile shrimp Litopenaeus vannamei: effects on growth and immune system

De forma general, las microalgas son fuente de alimento indispensable durante las primeras fases de desarrollo de los camarones marinos. Algunas microalgas, como la Arthrospira platensis, son ricas en substancias antioxidantes, y tienen la capacidad de retirar compuestos tóxicos del agua en los sistemas de producción acuícola. De este modo, constituimos un experimento con dos tratamientos triplicados, donde se evaluó la aplicación de biomasa filtrada de microalga A. platensis como suplemento alimenticio para camarón blanco del Pacífico, Litopenaeus vannamei. Se utilizó un sistema de cultivo estático de seis unidades, con volumen útil de 250 litros de agua marina (30 ppt), donde se sembraron 300 camarones m-2 con peso inicial de 0,7±0,2 g. Al final del experimento (42 días) se evaluaron parámetros inmunológicos y de desempeño zootécnico. Los camarones alimentados con A. platensis como como suplemento fueron signicativamente mayores que los camarones del tratamiento control y no presentaron diferencias en la supervivencia. Igualmente, se obtuvieron mejores resultados en los parámetros inmunológicos del tratamiento con inclusión de microalga. De esta forma, al suministrar la microalga como alimento suplementario al camarón L. vannamei, crecimiento y sistema inmunológico se vieron favorecidos.

Microalgae is an important food source during the early stages of marine shrimps. Some microalgae such as Arthrospira platensis, are rich in antioxidant substances and also have the capacity to remove toxics compounds from the water in aquaculture systems. The trial consisted in two treatements by triplicate, where the inclusion of filtered microalgae A. platensis as feed supplementation during production of juvenile Litopenaeus vannamei, was assessed. The experimental desing was based on a static system with six 250-L tanks with marine wáter (30 PSU), stocked 105 shirmps (300 shrimp m-2) with an average wheight of 0,7 ±0,2 g. At the end of the fed trial (42 days), the zootechnical and immunological parameters of shrimps were evaluated. Significatives differences among the treatments were found for both parameters. Shrimps that received supplementation of microalgae A. platensis showed higher growth and better response of the immune system. Thus, these results allow to conclude that the supplementation of filtered microalgae A. platensis improve growth and immunological parameters of white shrimp L. vannamei.

Growth of Critically Endangered annual fish Austrolebias wolterstorffi (Cyprinodontiformes: Rivulidae) at different temperatures

Given the importance of knowledge of the biology of endangered species for the planning of conservation and management efforts, the aim of this study was to investigate the influence of temperature on the growth of Austrolebias wolterstorffi (Ahl, 1924). To clarify the thermal influence on the growth of the species, temperatures of 16, 20, 24 , and 28°C were tested in triplicate. The present study showed that a water temperature of 28°C is detrimental to the growth of the species. Among the other tested temperatures, it was found that the optimum temperature for growth decreases as an individual ages and is slightly lower for females. It was demonstrated here that males reach a higher weight and length, and grow faster than females, reaching sexual maturity earlier. To optimize the growth of this species in captivity, the ideal temperature of the water during the initial life period is 24°C, until after puberty when the temperature should decrease to about 21°C.(AU)

Devido à importância do conhecimento da biologia das espécies ameaçadas de extinção para o planejamento de ações de conservação e manejo, o objetivo deste estudo foi investigar a influência da temperatura sobre o crescimento de Austrolebias wolterstorffi (Ahl, 1924). Para verificar a influência da temperatura no crescimento da espécie, as temperaturas de 16, 20, 24 e 28° C foram testadas em triplicata. O presente estudo mostrou que a temperatura da água de 28° C é prejudicial para o crescimento da espécie. Entre as outras temperaturas testadas, verificou-se que a temperatura ótima para o crescimento diminui ao longo da vida e é ligeiramente menor para as fêmeas. Foi demonstrado aqui que os machos alcançam um maior peso e comprimento e crescem mais rápido do que as fêmeas, atingindo a maturidade sexual anteriormente. Para otimizar o crescimento da espécie em cativeiro, a temperatura ideal da água durante o período inicial de vida é de 24° C, já após a puberdade, a temperatura deverá diminuir para cerca de 21°C.(AU)

Histopathological and Immunohistochemical Diagnostic of Carcinosarcoma of Mandible in a Rainbowtrout (Onchorhyincus mykiss)

Background: The most common health problems described in fishes are noninfectious, infectious, and metabolic disorders. Fishes have neoplasias that are similar to those observed in mammals. Though these neoplasias do not cause economic losses to aquaculture, they have aroused a crescent interest from the comparative pathology’s point of view. Neoplasias of the oral cavity in fishes are usually reported as individual cases, but mandible tumors are not common, and most of them are squamous cells carcinomas. The aim of this study is to report a case of carcinosarcoma of the mandible in a rainbow trout (Oncorhynchus mykiss), obtained from a trout farm in Campos do Jordão, São Paulo, Brazil. Case: The fish underwent necropsy and tissue samples were collected and fixed with a buffer-neutralized formalin solution, which were then embedded in paraffin, sectioned in 5 μm sections and stained with hematoxylin-eosin. The histological sections were stained for immunohistochemical procedures, according to a modified avidin-biotin-peroxidase complex technique. Slides containing tissue were deparaffinized with xylol and rehydrated with alcohol of different grades. The endogenous peroxidase activity was blocked by incubating the slides for 20 min at 0.3% H2O2 in a solution of 5% methanol. After rinsing the slides in water and in a PBS/0.05%-Tween 20 solution, they were incubated in normal serum diluted 1:100 containing 10% bovine albumin in PBS (BSA), at room temperature for 30 min in humid chamber. After incubation, the primary anti-cytokeratin and anti-vimentin antibody was added to a 1:200 dilution in 10% PBS-BSA, and the slides were incubated until the next day at 41oC in humid chamber. The slides were then rinsed in PBS and incubated for 7 min in a 50 mL 30.3-diaminobenzidine solution containing 1% PBS-BSA in 50 mL H2O2. Hematoxylin was used for counterstaining. The immunohistochemical analysis showed a tumor with epithelial and mesenchymatous neoplastic components.(...)

Histopathological and Immunohistochemical Diagnostic of Carcinosarcoma of Mandible in a Rainbowtrout (Onchorhyincus mykiss)

Background: The most common health problems described in fishes are noninfectious, infectious, and metabolic disorders. Fishes have neoplasias that are similar to those observed in mammals. Though these neoplasias do not cause economic losses to aquaculture, they have aroused a crescent interest from the comparative pathologys point of view. Neoplasias of the oral cavity in fishes are usually reported as individual cases, but mandible tumors are not common, and most of them are squamous cells carcinomas. The aim of this study is to report a case of carcinosarcoma of the mandible in a rainbow trout (Oncorhynchus mykiss), obtained from a trout farm in Campos do Jordão, São Paulo, Brazil. Case: The fish underwent necropsy and tissue samples were collected and fixed with a buffer-neutralized formalin solution, which were then embedded in paraffin, sectioned in 5 μm sections and stained with hematoxylin-eosin. The histological sections were stained for immunohistochemical procedures, according to a modified avidin-biotin-peroxidase complex technique. Slides containing tissue were deparaffinized with xylol and rehydrated with alcohol of different grades. The endogenous peroxidase activity was blocked by incubating the slides for 20 min at 0.3% H2O2 in a solution of 5% methanol. After rinsing the slides in water and in a PBS/0.05%-Tween 20 solution, they were incubated in normal serum diluted 1:100 containing 10% bovine albumin in PBS (BSA), at room temperature for 30 min in humid chamber. After incubation, the primary anti-cytokeratin and anti-vimentin antibody was added to a 1:200 dilution in 10% PBS-BSA, and the slides were incubated until the next day at 41oC in humid chamber. The slides were then rinsed in PBS and incubated for 7 min in a 50 mL 30.3-diaminobenzidine solution containing 1% PBS-BSA in 50 mL H2O2. Hematoxylin was used for counterstaining. The immunohistochemical analysis showed a tumor with epithelial and mesenchymatous neoplastic components.(...)(AU)