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)

Pigmentation of the rainbow trout (Oncorhynchus mykiss) with oil-extracted astaxanthin from the langostilla (Pleuroncodes planipes).

The effect of oil-extracted astaxanthin from the red crab or langostilla (Pleuroncodes planipes) on the growth and pigmentation of forty five rainbow trouts (Oncorhynchus mykiss) was investigated by feeding a test diet supplemented with 75 mg/kg of astaxanthin during six weeks and compared with a control diet. The oil-extraction process of the pigment is described. Weight, flesh astaxanthin concentration, and color (L*, a*, b*) of the flesh were measured at 0, 3, and 6 weeks. No apparent effect of astaxanthin supplementation was observed on fish development. In spite of the low free astaxanthin amount in the diet (8%), an acceptable carotenoid concentration in the flesh (3.60 +/- 0.78 mg/kg, w/w), and a red hue (H(ab)o = 44.13 +/- 2.36) were obtained at the end of the study. The red hue was strongly correlated with the carotenoid concentration (r = 0.98).

Light and electron microscopic study of germ cells of the rainbow trout (oncorhynchus mykiss)

El objetivo de este trabajo es describir las características morfológicas de las células germinales de la trucha arcoiris Oncorhynchus mykiss, durante los estados pregonádico, gonádico y gónada tempranamente diferenciada. Las células germinales primordiales se identificaron en los embriones de 11-35 días postfecundación (125-300ºD), correspondiendo al estado pregonádico. Son células grandes con un núcleo voluminoso y pálido. El citoplasma tiene un volumen mínimo y aparece homogéneo con ribosomas y mitocondrias distribuidas regularmente. También se presentan gránulos oscuros, semejantes a inclusiones vitelinas. El esbozo gonádico se forma a los 40 días postfecundación (400ºD) y la diferenciación de la gónada, en ovario o testículo, se inicia a los 150 días (1500ºD). La estructura ovárica, al inicio de la diferenciación, presenta oocitos rodeados por células prefoliculares. El testículo tempranamente diferenciado se identifica por la presencia de acúmulos de espermatogonias dispuestos en cistos. El estudio que se presenta contribuye a mejorar la caracterización de las células germinativas de la trucha arcoiris y también entregar información respecto a la cronología de los estados principales de la diferenciación gonadal, en embriones y alevines mantenidos a una temperatura constante de 10ºC