Abstract The purpose of this study was to describe the structure of the midgut (hepatopancreas and intestine) in the endemic species, Macrobrachium carcinus. Thirty specimens were collected, and the midgut was fixed in Bouin's solution for histological and histochemical analyzes by light microscopy. The hepatopancreas consists of two lobes that connect to the end of the stomach by primary ducts, which originate secondary tubules or hepatopancreatic ducts, that branch into hepatopancreatic tubules. The hepatopancreatic duct presents a columnar epithelium composed of R- and F- cells with evident brush borders for absorption and storage. The hepatopancreatic tubule is lined by epithelium with five cell types (E, F, R, B, and M). The distal region presents all cell types, with a predominance of E-cells that correspond to epithelial renewal. The middle region presents F- and B- cells, characteristic of extracellular and intracellular digestion. The proximal region, with B- and R- cells, performs the final digestion, storage, and extrusion of the cells with waste material. The intestine is lined by a single cell type with an evident brush border, suggesting luminal absorption. This cellular arrangement along the length of the midgut proposes distinct morpho-functional characteristics of digestion, absorption, and storage in this species.

The aim of this study was to characterize the normal structure of the liver of Hemisorubim platyrhynchos, a carnivorous freshwater catfish found in Neotropical region, using gross anatomy, histology and histochemistry. Anatomically, the liver presents C-shaped and only two lobes: smaller right and bigger left. The gallbladder is located in right lobe and shows elongated shaped. Histological analysis demonstrated that the hepatic parenchyma is made of two hepatocytes plates surrounded by sinusoids. The hepatocytes are polygonal-shaped cells, with spherical nucleus and a dark prominent nucleolus. The cytoplasm presents large amount of lipids and glycogen deposits PAS positives. There are no hepatic lobules or portal triads. Bile ducts are lined by columnar epithelial cells with apical mucosubstances PAS and AB positive. Furthermore, the liver presents melano-macrophages centers, distributed next to the blood vessels and bile ducts, constituted by cells accumulating pigments, whose presence may be related to the nutritional status of the fish. Moreover pancreatic tissue was observed in visceral portion of liver, formed by exocrine pancreatic tissue and islet organ, constituting an extrahepatic pancreas.

El objetivo de este estudio fue caracterizar la estructura normal del hígado de Hemisorubim platyrhynchos, un bagre carnívoro de agua dulce encontrado en la región neotropical, utilizando anatomía macroscópica, histología e histoquímica de mucosustancias. Anatómicamente, el hígado presenta una forma de C y sólo dos lóbulos de tamaño diferente: menor derecho y mayor izquierdo. La vesícula biliar se encuentra en el lóbulo derecho y presenta forma alargada. El análisis histológico demostró que el parénquima hepático está hecho de dos placas de hepatocitos rodeados por sinusoides. Los hepatocitos son células poligonales con núcleo esférico y un nucléolo oscuro prominente. El citoplasma presenta gran cantidad de lípidos y depósitos de glucógeno PAS positivos. No hay lóbulos hepáticos o triadas portal. Los conductos biliares están revestidos por células columnares epiteliales con mucosustancias apicales PAS y AB positivos. Además, el hígado presenta centros de melanomacrófagos, distribuidos junto a los vasos sanguíneos y conductos biliares, constituidos por células que acumulan pigmentos, cuya presencia puede estar relacionada con el estado nutricional de los peces. Por otra parte, el tejido pancreático se observó en la porción visceral de hígado, formado por tejido pancreático exocrino y órgano islote, que constituye un páncreas extrahepático.

O presente estudo descreve as fases de maturação testicular (associando o desenvolvimento das células germinativas e as alterações morfológicas sofridas pelo epitélio germinativo ao longo do ano), e a morfologia testicular do tucunaré amarelo Cichla kelberi, relacionando a outras espécies. Com este propósito, 78 indivíduos foram estudados de acordo com técnicas convencionais para microscopia de luz. Os testículos em C. kelberi foram classificados como lobular espermatogonial irrestrito, uma característica apomórfica encontrada nos grupos recentes dos teleósteos. Além disso, cinco fases de maturação testicular foram definidas para C. kelberi: Fase Preparatória; Desenvolvimento Inicial do epitélio germinativo; Desenvolvimento Intermediário do epitélio; Desenvolvimento Final do epitélio germinativo e Regressão. Classificações similares foram descritas para outras espécies, indicando que a classificação gonadal baseada nesta proposta, pode ser aplicada a muitas espécies de peixes. Entretanto, apesar desta similaridade, o ciclo reprodutivo testicular de C. kelberisegue um padrão diferente na fase de Regressão, na qual a reestruturação gonadal e a proliferação espermatogonial ocorrem ao mesmo tempo. Deste modo, os testículos em C. kelberinunca retornam à fase Preparatória para começar um novo ciclo reprodutivo nesta espécie. Este fato também explica a ausência de indivíduos totalmente esgotados após seu primeiro ciclo reprodutivo.

The present study describes the testicular maturation phases (associating the germ cells development and the morphological changes suffered by the germinal epithelium along the whole year), and the testicular morphology in the yellow peacock bass Cichla kelberi, relating it to other species. For this purpose, 78 specimens were studied according conventional techniques of light microscope. The testes in C. kelberi were classified as unrestricted spermatogonial lobular, an apomorphic characteristic in the recent groups of Teleost. Furthermore, were defined five testicular maturation phases: Preparatory phase; Early Germinal Epithelium Development; Mid Germinal Epithelium Development; Late Germinal Epithelium Development and; Regression. Similar classifications were described to other species indicating that the testicular classifications based on this propose, can be applied to lots of fishes. However, besides it similarity, the testicular reproductive cycle of C. kelberifollows a different pattern in the Regression phase, on which the gonadal restructuration and the spermatogonial proliferation gathers at the same time. So, the testes in C. kelberi never return to the Preparatory phase to start a new reproductive cycle, being this one present only at the first reproductive cycle in this species. This fact also explains the absence of individuals totally spent after their first reproductive cycle.

The aim of the present study was to analyze the ultrastructural aspects of spermatogenesis in Phalloceros caudimaculatus, during cell proliferation. The parenchyma is organized morphologically as lobular restricted spermatogonial testis. Spermiogenesis in this species is characterized by four morphological stages of development (spermatids S1 through S4). The mature spermatids and spermatozoa heads are situated at the periphery of the cyst surrounded by the cytoplasm of the Sertoli cells. The germ cell's ultrastructure and spermatogenesis in P. caudimaculatus are very similar to that of other poeciliids.

El objetivo del presente estudio fue analizar los aspectos ultraestructurales de la espermatogénesis en Phalloceros caudimaculatus, durante el periodo de proliferación celular. El parénquima testicular está morfológicamente organizado como lobular espermatogonial restricto. La espermiogénesis en esta especie se caracteriza por cuatro etapas morfológicas de desarrollo (espermátidas S1 hasta S4). Las cabezas de las espermátidas maduras y espermatozoides están situadas en la periferia de los cistos, rodeados por el citoplasma de las células de Sertoli. La ultraestructura de las células germinativas y la espermatogénesis en P. caudimaculatus son muy similares a las de otros poecílideos.

In decapod crustaceans, the digestive gland is concerned with the digestion, absorption of nutrients, the storage of reserves and excretion. The metabolism and the histological and histochemical changes of the hepatopancreas are observed in response to physiological demands as moult, reproduction, digestive process. Thus the hepatopancreas structure should be recognized to provide important morphological information to future studies involving the nutrition requirements of freshwater prawn culture. In this study, second-generation Macrobrachium amazonicum produced from wild broodstock collected in the state of Para in Brazil were used. Thirty adult male and female M. amazonicum were selected and randomly transferred to five experimental units for macroscopic and microscopic studies. The hepatopancreas of M. amazonicum is a large, yellowish-brown, compact organ, which occupies much of the cephalothoracic cavity. It has right and left halves that are enclosed together in a laminar connective tissue capsule, and at the same time they are separated by an interstitial connective tissue. The two halves are thereby called the right and left hepatopancreatic lobes. The principal tubule gives rise to four secondary tubules at each hepatopancreatic lobe. The morphological and functional unit consists of a blind-ended hepatopancreatic tubule, considered in the present study as the hepatopancreatic lobule. Each hepatopancreatic tubule can be subdivided into distal, medial and proximal zones. The hepatopancreatic tubule is lined by a pseudostratified epithelium that consists of five different cell types, which include the E-cell (embryonic), F-cell (fibrillar), B-cell (blister-like), R-cell (resorptive) and M-cell (midgut or basal). It is important to emphasize that the function of each cell type in the hepatopancreas during the digestive cycle is not yet established for decapods.

La glándula digestiva en los crustáceos decápodos asume las funciones de digestión, absorción de nutrientes, almacenamiento de las reservas energéticas y excreción de metabolitos. El metabolismo y las alteraciones histológicas e histoquímicas son observados como respuesta a necesidades fisiológicas, tales como: muda, reproducción y procesos digestivos. Por lo tanto, se requiere conocer la estructura histológica del hepatopancreas con el fin de reunir información morfológica para futuros estudios que consideren las necesidades nutricionales para el cultivo de los camarones de agua dulce. Fueran utilizados 30 animales, machos y hembras de Macrobrachium amazonicum, producidos a partir de reproductores colectados en el Estado de Para, Brasil. Las observaciones macro y microscópicas permitieron concluir que el hepatopancreas del M. amazonicum es un órgano grande y compacto de color amarillo tendiendo a marrón, que ocupa la mayor parte de la cavidad céfalo-torácica. El órgano presenta dos mitades, derecha y izquierda, las cuales están envueltas por una cápsula de tejido conjuntivo, y al mismo tiempo, separadas por tejido conectivo intersticial. Las dos mitades del órgano son identificadas como lobos derecho e izquierdo. Cada lobo presenta un túbulo principal que origina cuatro túbulos secundarios. Por lo tanto, la unidad morfofuncional del hepatopancreas consiste en un túbulo hepatopancreático de fondo ciego, considerado en esta investigación como lóbulo hepatopancreático. Cada lóbulo hepatopancreático puede ser dividido en 3 regiones: distal, media y proximal, y en su totalidad, se observa revestido por epitelio seudo estratificado que reúne cinco tipos celulares: célula E (embrionaria), célula F (fibrilar), célula B (globosa), célula R (reabsortiva) y célula M (basal). Es importante enfatizar que la función de cada tipo celular del hepatopancreas no está todavía aclarada para los decápodos.

The epithelial principal cells are the predominant cell type of the epididymis. These cells have been shown to be both secretory and endocytic cells. The apical region of the cytoplasm of principal cells in the mongrel dog are located close to the cell apex and tubular lumen, and shown microvilli at the luminal border and present a endocytic apparatus, that consists of coated pits and vesicles, endosomes of varying size, multivesicular bodies, and lysosomes. The endosomes, multivesicular bodies and lysosomes contained the electron-dense patches. These results suggest that principal cells of the epididymis in the dog as possess a highly developed endocytic apparatus play a role in endocytosis. These cells function are similarly to the related in other mammals, in performing endocytosis.

Las células epiteliales principales son el tipo de célula que predominan en el epidídimo. Estas células han demostrado ser secretoras y endocíticas. La región apical del citoplasma de las células principales en el perro Mongrel, se encuentran muy cerca del ápice celular y lumen tubular, mostrando microvellosidades en el límite luminal y un aparato endocítico, el que consiste en depresiones recubiertas y vesículas, endosomas de diversos tamaños, cuerpos multivesiculares y lisosomas. Los endosomas, cuerpos multivesiculares y lisosomas contienen gránulos electrodensos. Estos resultados sugieren que las células principales del epidídimo, en el perro, poseen un aparato endocítico altamente desarrollado que juega un importante rol en la endocitosis. Estas células funcionan de manera similar a la correspondiente en otros mamíferos, en el desempeño de endocitosis.

The cisternae of the Golgi apparatus of dog epididymal principal cells were labeled by the zinc iodide-osmium tetroxide method (ZIO). These cisternae were observed in the supranuclear region of the cytoplasm of the epididymal principal cells. Abundant endoplasmic reticulum cisternae, multivesicular bodies, mitochondria, lysosomes and vesicular elements of variable size were also found in this region, all associated with the sacks of the well-developed Golgi apparatus. The use of the ZIO method facilitates the observation and identification of the cisternae of the Golgi apparatus, thus permitting a correlation between structure and function in the so-called Golgi area. These ultrastructural characteristics support the secretory role of epididymal principal cells in the dog

La cisterna del aparato de Golgi de las células principales del epidídimo del perro, fueron tratados con el método de tetróxido de zinc iodide-osmium (ZIO). Estas cisternas fueron observadas en la región supranuclear del citoplasma de las células principales del epidídimo. Abundante cisternas del retículo endoplasmático, cuerpos multivesiculares, mitocondrias, lisosomas y elementos vesiculares de tamaño variable, fueron encontrados en esta región, todos asociados con los sacos del aparato de Golgi maduro. El uso del método de ZIO facilita la observación e identificación del aparato de Golgi, permitiendo efectuar una correlación entre estructura y función en el área de Golgi. Estas características estructurales suponen el rol secretorio de las células epididimarias principales en el perro

Objetivou-se, neste estudo, avaliar os efeitos de diferentes níveis de fibra bruta e de óleo de soja em rações para a tilápia do Nilo. Utilizaram-se 24 aquários circulares de 250 L, dotados de sistema individual de reabastecimento de água e aquecimento. A densidade de estocagem foi de sete peixes/aquário, totalizando 168 peixes, com peso inicial médio de 6,41±0,05 g. Ganho de peso, conversão alimentar aparente, taxa de crescimento específico e taxa de eficiência protéica foram avaliados. Foram analisados a composição química e o rendimento de carcaça, gordura visceral e índice hepatossomático dos peixes. O experimento foi realizado segundo um esquema fatorial 3 x 2 (três níveis de fibra bruta 6,00; 9,00 e 12,00%, com e sem óleo de soja) no delineamento inteiramente ao acaso com quatro repetições. Verificou-se que a fibra interfere de forma significativa na digestibilidade aparente da dieta, com ação positiva para a proteína e negativa para a matéria seca, não interferindo na digestibilidade do extrato etéreo; que a fibra bruta não tem efeito significativo sobre o rendimento de carcaça e no depósito de gordura visceral, mas a inclusão de óleo à ração tem efeito significativo no depósito de gordura visceral; que a fibra resulta em efeito significativo na composição química da carcaça (teor de água e proteína), não tendo efeito sobre sua composição em gordura; e que a inclusão de gordura à ração diminui e eleva de forma significativa, respectivamente, o conteúdo de proteína e extrato etéreo da carcaça. Concluiu-se que, na fase de alevinagem (6,40 a 31,00g), pode-se utilizar na dieta da tilápia do Nilo até 9,00% de fibra bruta, e que a suplementação de níveis excessivos de lipídeos na dieta piora a composição da carcaça e resulta em maior depósito de gordura visceral.

The objective of this research was to evaluate the effects of different crude fiber and soybean oil levels in diets for Tilapia Nile. Twenty-four circular fishbowls of 250 liters, with an individual system of water replenishment and heating, were used. The stocking rate was of seven fishes/fishbowl, totalizing 168 fishes, with average initial weight of 6.41±0.05 g. Weight gain, apparent feed:gain ratio, specific growing rate and protein efficiency rate were evaluated. The chemical composition and carcass yield, eviscerated carcass and hepatossomatic index were also studied. A completely randomized design was used, in a 3 x 2 factorial scheme, being three crude fiber levels (6.00, 9.00%, and 12.00%), and two soybean oil levels (0.0 and 10.0%), with four replicates. It was verified that it is possible to use, in the diet, levels up to 12.00% of crude fiber and its excess tends to decrease the weight gain and the protein efficiency rate, besides worsening the feed:gain ratio; the fiber significantly affect the dietary apparent digestibility, with positive and negative effect on the protein and dry matter digestibility, respectively, and without effect on the ether extract digestibility; the crude fiber did not significantly affect the carcass yield and the eviscerated fat deposition. However, the oil addition to the diet showed significant effect on the eviscerated fat deposition; the fiber resulted in significant effect on the carcass chemical composition of the carcass (water and protein contents), without effect on the fat composition; and the fat addition to the diet significantly decreased and increased, respectively, the carcass protein and ether extract contents. It was concluded that, in the growing phase (from 6.40 to 31.00 g), the dietary crude fiber levels up to 9.00% can be fed for Nile tilapia and the supplementation of high dietary lipid levels decrease the carcass composition and result in higher eviscerated fat deposition.

O Colossoma macropomun, peixe teleósteo com hábito natatório intenso, apresentou ventrículo cardíaco com forma piramidal e miocárdio com estrutura mista, sendo formada por uma camada compacta externa e outra esponjosa interna. Esta estrutura bilaminar diferenciada, atualmente, tem sido correlacionada com o hábito natatório e com a morfologia ventricular.

The neotropical teleost fish Colossoma macropomun an active swimming species showed cardiac ventricle with pyramidal shape and myocardium with mixed structure. The myocardium presented an outer compact layer and an inner spongy layer whose particular bilaminar structure hitherto has been correlated to swimmer habit as well as to ventricular shape.

O ducto epididimário, no cão, acha-se revestido por epitélio colunar pseudoestratificado, com população celular constituída por células principais, basais e apicais, presentes em todas as regiões. Este epitélio é circundado pelo estroma peritubular. O epitélio do segmento inicial epididimário possui a maior altura, que diminui progressivamente em direção à cauda epididimária. Ocorre um aumento progressivo do lúmen tubular através das diferentes regiões, sendo maior na região da cauda epididimária, configurando um local de estocagem de espermatozóides.

The epithelium lining of the epididymal duct is pseudostratified columnar and the cell population is comprised of principal, basal, and apical cells. The stroma periductal, is a well developed framework surrounding the tubule. Epididymal epithelial heights were maximal in the initial segment and minimal in the tail. Luminal diameter was just the reverse of the last pattern, e.g., it increased along the length of the duct.

The ductus epididymidis of the dog is lined by a pseudostratified columnar epithelium. The boundary tissue of the epididymis, surrounds the epithelium, and is divided into periductal stroma and tubular interstitium. Principal cells were observed in the luminal surface of the epithelium. Numerous stereocilia lined the luminal surface of principal cells. These results are compared with previous findings observed in the epididymis of other species

El epidídimo en el perro está revestido por epitelio de tipo columnar pseudoestratificado, encontrándose el tejido conjuntivo inmediatamente debajo de él. El tejido conjuntivo epididimario consiste de estroma e intersticio. Fueron observadas células epiteliales con microvellosidades en el lumen del conducto. Se comparan los resultados obtenidos con los reportados por diversos autores ens otros mamíferos

Este trabalho avaliou o efeito do farelo e da farinha de semente de algodão no ganho de peso e na atividade testicular de alevinos de tilápia-do-nilo (Oreochromis niloticus). Cento e cinqüenta alevinos com peso médio inicial de 1,26 g foram mantidos em aquários de 45 L, com renovação contínua d'água, e alimentados por 120 dias com dietas isoprotéicas (28% PB) e isocalóricas (4.030 kcal EB/kg de ração) contendo 0%, 2%, 4% e 6% de semente de algodão descorticada e moída, e 24% de farelo de algodão. Foi observado que os níveis avaliados interferem na atividade testicular, diminuindo a espermatogênese, embora não tenham comprometido de forma significativa o ganho de peso dos alevinos.

This experiment evaluated the effect of cottonseed meal or cottonseed flour on growth and testis activity of Nile tilapia fingerlings (Oreochromis niloticus). One hundred and fifty fingerlings with mean initial weight of 1.26 g were maintained in 45 L aquaria with continuous water supply. Fish were fed in isoproteic (28% CP) and isoenergetic (4,030 kcal CE/kg of ration) diets during 120 days. The experimental diets comprised a control diet, without cottonseed flour or meal, and diets containing 2%, 4% and 6% of cottonseed flour and 24% cottonseed meal. The results indicated that the use of seed flour or meal should be limited since at the tested levels they interferred with testis activity although they had not adversely affected the weight gain of fingerlings.

Este experimento foi realizado para avaliar o efeito do farelo e da farinha de algodão no comportamento reprodutivo e na atividade testicular de reprodutores de tilápia do Nilo. Vinte e cinco peixes receberam dietas contendo 0; 2; 4; e 6% de semente de algodão descorticada e moída e 24,0% de farelo de algodão. O comportamento reprodutivo foi observado e a construção de ninhos, corte e desova, avaliadas. Aos 90 dias, as gônadas dos machos foram avaliadas microscopicamente. O grupo controle (farelo de algodão) obteve maior número de desovas. Os peixes alimentados com semente ou farelo de algodão, apesar de não terem apresentado o mesmo número de desovas, construíram ninhos e fizeram a corte. A análise histológica dos testículos demonstrou que a adição de 24,0% de farelo ou níveis de 2,0% ou superiores da farinha influiu na atividade testicular. O gossipol presente na farinha ou farelo de algodão teve efeito negativa nas gônadas destes animais.

This experiment was conducted to evaluate the effect of cottonseed meal and cotton seed flour on the reproductive behavior and on the testis activity of Nile tilapia broodstock. Twenty-five fishes were fed diets containing 0, 2, 4 and 6% ground cottonseed flour and 24% cottonseed meal (CSM). The reproductive behavior of the fishes was daily observed and the nest construction, courtship and spawning were evaluated. At 90 days, the males gonads were microscopically evaluated. The control group (soybean meal) showed higher number of spawning. The fishes fed diets with cottonseed flour or cottonseed meal, despite of had not presented the same number of spawning, showed nest construction and courtship. The histology analysis of the testis indicated that the addition of 24% of cottonseed meal or 2% or higher of cottonseed flour affected the testis activity. The gossypol present in the cottonseed flour or cottonseed meal had a negative effect on the gonads of these animals.