Ciclo reprodutivo de Salmo irideus Gibbons (Pisces, Salmoniformes) mantidos em sistema de cultivo intensivo: caracterização microscópica dos ovários

Five adults female specimens of Salmo irideus Gibbons, were collected every month, during eleven months for microscopic identification of their cyclic gonadal modulation. For microscopic analysis ovary were excised in their medial and caudal portions and fixed in Bowin's fluid. The results showed that the reproductive cycle of the female of S. irideus can be classified as follows: maturing (early and later), ripenning and spent. Microscopical analysis showed that in early maturing there is predominance of ovocytes in initial vitellogenesis; in later maturing the predominance is of ovocytes at the end vitellogenesis; in ripenning these predominance is of mature ovocytes; in the spent, atresic and empty follicles predominate.Cinco exemplares de fêmeas adultas de Salmo irideus Gibbons foram coletados mensalmente, durante onze meses, para estudos microscópicos do ciclo reprodutivo. Para análise microscópica os ovários foram amostrados no seu terço medial e caudal e fixados em liquido de Bouin. Os resultados mostram que o ciclo reprodutivo das fêmeas de Salmo irideus pode ser classificado em maturação (inicial a avançada), reprodução e esgotado. Microscopicamente, na maturação inicial ocorra predominância de ovócitos em início de vitelogênese; na maturação avançada observa-se predominância de ovócitos na fase final de vitelogênese; no estádio de reprodução a maioria dos ovócitos estão maduros e nos exemplares esgotados, há predomínio de folículos vazios e ovócitos atrésicos. As ovogônias estão presentes em todos os estádios de desenvolvimento gonadal

Caviar substitute produced from roes of rainbow trout (Oncorhynchus mykiss)

ABSTRACT. The caviar substitute is obtained from processed fish roe, resulting in a product similar to the authentic caviar, prepared with sturgeon roe. The objective of this study was to develop a caviar substitute from roes of rainbow trout, Oncorhynchus mykiss. Four treatments were tested and we followed the steps of saline wash, drain, immersion in saline solution containing lactic acid for pH adjustment (4.3 to 4.5), salt addition (1.5 or 3%), traditional pasteurization or fast heat treatment, cooling and storage (0 to 4°C). The products were subjected to the physical, chemical, microbiological and sensory analyses and showed stability and safety for consumption up to 180 days in storage under refrigeration (0 to 4°C). Consumers showed preference for product containing 1.5% NaCl and subjected to fast heat treatment. The results suggest that caviar substitute developed with rainbow trout roes presents potential to production. Keywords: heat treatment, safety for consumption, stability. Sucedâneo de caviar produzido com ovas de truta arco-íris (Oncorhynchus mykiss) RESUMO. O sucedâneo de caviar é obtido a partir de ovas de peixe processado, resultando em um produto análogo ao caviar legítimo, preparado com ovas de esturjão. O objetivo deste estudo foi desenvolver o sucedâneo de caviar de ovas de truta arco-íris, Oncorhynchus mykiss. Foram testados quatro tratamentos para o produto, seguindo as etapas de lavagem em solução salina, drenagem, imersão em solução salina adicionada de ácido lático para ajuste do pH (4,3 a 4,5), adição de sal (1,5 ou 3%), pasteurização tradicional ou tratamento térmico rápido, resfriamento e armazenamento (0 a 4°C). Os produtos, submetidos a análises físico-químicas, microbiológica e sensorial, apresentaram-se estáveis e seguros para o consumo até 180 dias, em estocagem sob refrigeração. Os consumidores apresentaram preferência pelo produto com 1,5% de NaCl e submetido ao tratamento térmico rápido. Os resultados sugerem que sucedâneo de caviar desenvolvido com ovas de truta arco-íris apresenta potencial para produção. Palavras-chave: tratamento térmico, segurança para consumo, estabilidade

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% H2 O2 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 41 o C 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 H2 O2. Hematoxylin was used for counterstaining. The immunohistochemical analysis showed a tumor with epithelial and mesenchymatous neoplastic components. The epithelial component presented an epidermoid carcinoma with well differentiated and keratinizing areas, in addition to other little differentiated, non-keratinizing areas. The mesenchymatous component presented a fibrosarcoma. The immunohistochemical analysis demonstrated signs of cytokeratin in carcinomatous elements and of vimentin in sarcomatous elements. Discussion: Fishes are valuable resources in human nutrition, medicine, science and leisure. Similarly to other poikilothermic vertebrates, fishes also develop benign and malign neoplasias. However, it is their infectious diseases that are more known and studied. Teleost fishes constitute the widest and most diverse class of vertebrates, with over 20,000 known species. The diversity and placement in the phylogenetic tree make teleost fishes the ideal objects for comparative carcinogenesis studies, which could allow a broader knowledge about basic neoplastic development mechanisms, in comparison to studies limited to mammal models only. According to our knowledge and considering the literature available on fish tumors, this is the first description of a carcinosarcoma of the mandible affecting a rainbow trout

Histopathological and Immunohistochemical Diagnostic of Carcinosarcoma of Mandible ina Rainbowtrout (Onchorhyncus 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 ?m 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. The epithelial component presented an epidermoid carcinoma with well differentiated and keratinizing areas, in addition to other little differentiated, non-keratinizing areas. The mesenchymatous component presented a fibrosarcoma. The immunohistochemical analysis demonstrated signs of cytokeratin in carcinomatous elements and of vimentin in sarcomatous elements. Discussion: Fishes are valuable resources in human nutrition, medicine, science and leisure. Similarly to other poikilothermic vertebrates, fishes also develop benign and malign neoplasias. However, it is their infectious diseases that are more known  and studied. Teleost fishes constitute the widest and most diverse class of vertebrates, with over 20,000 known species. The diversity and placement in the phylogenetic tree make teleost fishes the ideal objects for comparative carcinogenesis studies, which could allow a broader knowledge about basic neoplastic development mechanisms, in comparison to studies limited to mammal models only. According to our knowledge and considering the literature available on fish tumors, this is the first description of a carcinosarcoma of the mandible affecting a rainbow trout

Cryopreservation of semen from functional sex-reversed genotypic females of the rainbow trout, Oncorhynchus mykiss

A criopreservação do sêmen de fêmeas masculinizadas de truta arco-íris tem como objetivo a racionalização do processo de produção de estoques 100% femininos. Para tal, foi coletado sêmen de machos normais (M) e de dois tipos de fêmeas genotípicas (R e G), masculinizadas pela administração oral de 17alfa-metiltestosterona. R foi obtido pela fertilização de ovócitos normais com sêmen de fêmeas masculinizadas enquanto G foi através de reprodução ginogenética. O sêmen foi diluído em uma solução crioprotetora (glicose 5,4 g, gema de ovo de galinha 10 ml, dimetil sulfóxido 10 ml, água destilada 80 ml) na razão de 1:3 (sêmen/diluidor), envasado em palhetas de 0,5 ml e congelado em um container tipo seco Cryopac CP-65, à temperatura de -180ºC. A descongelação foi feita em água a 70ºC por 3 segundos. As taxas de fertilização obtidas, não revelaram diferença estatística significativa (P0.05) among thawed semen groups (M = 73.1±11.5%; R = 67.2±23.6%; G = 64±5.8%), confirming that the freezing methodology used was efficient to cryopreserve semen of all three trout groups.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

<b>Caviar substitute produced from roes of rainbow trout (<i>Oncorhynchus mykiss</i>)

The caviar substitute is obtained from processed fish roe, resulting in a product similar to the authentic caviar, prepared with sturgeon roe. The objective of this study was to develop a caviar substitute from roes of rainbow trout, Oncorhynchus mykiss. Four treatments were tested and we followed the steps of saline wash, drain, immersion in saline solution containing lactic acid for pH adjustment (4.3 to 4.5), salt addition (1.5 or 3%), traditional pasteurization or fast heat treatment, cooling and storage (0 to 4°C). The products were subjected to the physical, chemical, microbiological and sensory analyses and showed stability and safety for consumption up to 180 days in storage under refrigeration (0 to 4°C). Consumers showed preference for product containing 1.5% NaCl and subjected to fast heat treatment. The results suggest that caviar substitute developed with rainbow trout roes presents potential to production

Daily mass balance of phosphorus and nitrogen in effluents of production sectors of trout farming system

Abstract Aim: The mass balance has recently been applied in Brazilian aquaculture. In relation to trout farming, few studies have used this methodology as environmental indicator, especially when considering each development stage of fish. The daily mass balance allows an estimate of nutrients discharge, because the sampling effort over 24 hours enables to monitor the variations throughout the day. This study aimed to identify the breeding sector (fingerlings, juveniles and adults) in trout farming contributes with the great discharge of phosphorus and nitrogen in the effluent. Methods The concentrations of total phosphorus (TP), orthophosphate (PO4-P), total nitrogen (TN) and ammonium (NH4-N) were determined in affluent and effluents of the production system. The environmental indicators were calculated based on the values of nutrients loads and by quantifying the daily discharge of nutrients from the mass balance method. Results Over the 24 hours, the trout farming exported an average of 0.26 kg TP, 0.11 kg PO4-P, 3.11 kg TN and 0.18 kg NH4-N. The discharge of phosphorus and nitrogen in the effluent was higher at night associated to feeding management (hours and feeding frequency) and the nocturnal habits of trout. The juvenile and adult sectors accounted for the greatest contribution of these nutrients, related the largest fish biomass and metabolism, supported by the feed conversion ratio of 1.95:1 and 2.01:1, respectively. Conclusion In order to reduce exports of phosphorus and nitrogen there is a need to adequate the feeding management (feeding frequency from two to four times per day according to the trout development stage; carry out feeding in times close at twilight due to the nocturnal habits of this specie; reduce excess of ration offered and use good quality ration considering the distinct nutritional requirements of each trout stage of development). Besides the mass balance, the feed conversion ratio is also an efficient tool to detect the efficiency of feed utilization; therefore, it is proposed its use as environmental indicator, aiming the aquaculture environmental sustainability