Histological, histochemical and ultrastructural characterization of the pancreas of the grass carp (Ctenopharyngodon idella)

The purpose of this study is to describe the histological, histochemical and ultrastructural features of pancreas of the grass carp (Ctenopharyngodon idella), one of the common herbivorous freshwater fish of Egypt. The pancreas is divided into exocrine and endocrine portions. Exocrine pancreatic tissues consists of scattered serous acini, and is observed in two forms: 1) disseminated in the spleen tissue, in mesentery around intestine and intestinal bulb, and 2) intrahepatically, around the branches of the portal vein. Two alveolar cell types are present in pancreatic acini; centroacinar cells and typical pyramidal acinar cells. Pancreatic stellate cells (PSC) are demonstrated in the perivascular and the periacinar space of the pancreas. The pancreatic acini gave positive reaction to PAS, Best's carmine, and osmium tetraoxide, and negative to alcian blue. The acini also show high lipase and alkaline phosphatase activity, and moderate activity for acid phosphatase. Scanning electron microscopy show apical microvilli of the acinar cells, and branched PSC extend their processes between the pancreatic cells. Ultrastructure of pancreatic acini reveals well-developed rER, membrane-bound zymogen granules, and abundant lipid droplets. The duct system is composed of intralobular duct, interlobular pancreatic duct and main duct opened in the intestinal bulb. The endocrine parts of the pancreas are organized as lightly staining Langerhan’s islets between exocrine acinar cells found in the liver, in mesenteries around the intestinal bulb and the intestine, and consisted of three cell types. Alpha cells were the most dominant cells, and were ovoid in shape. Beta cells were polyhedral in shape, and they grouped in small clusters. Delta cells were small fusiform, argyrophilic cells. In conclusion, the present study revealed that the exocrine portion of the pancreas of the grass carp had two forms, disseminated and intrahepatic, with characteristic cellular and histochemical components, and an endocrine portion that consisted of Alpha, Beta and Delta cells

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Biomarcadores etológicos no invasivos de estrés ambiental: estudio comparativo en dos teleosteos de ecosistemas de la región pampeana argentina / Non invasive behavioural biomarkers of environmental stress: comparative study on two teleosts from ecosystems of the pampean region of Argentine

Mediante un dispositivo de registro automático se estudió el efecto de la exposición a soluciones subletales de Cd2+ (0.3 mg. L ) sobre algunos parámetros etológicos de juveniles de Cyprinus carpio (carpa común) y de Astyanax fasciatus (“mojarra”). Se evaluó el efecto del metal sobre la actividad natatoria total y las preferencias altitudinales y laterales de los peces. Los tres parámetros se registraron simultáneamente mediante un dispositivo original. Se evaluaron los niveles “normales” o estándar de dichos parámetros (los peces en agua potable, control) y los alcanzados por los mismos individuos tras su exposición al tóxico de referencia (Cd). El metal provocó una depresión de la actividad natatoria total alcanzando una magnitud comparable en ambas especies. La preferencia altitudinal, también resultó modificada: C. carpio se halló con mayor frecuencia en la capa superior de los acuarios mientras que A. fasciatus se ubicó en las inferiores. En cuanto a la preferencia lateral, los individuos de ambas especies evitaron la franja vertical donde se producía el goteo de la solución de Cd; si bien esta respuesta espacial de los animales no siguió un patrón definido fue más marcada en las carpas. Todas las respuestas se pusieron de manifiesto inmediatamente después de haberse iniciado la exposición al Cd. El método resultó sensible y apto para el seguimiento de los parámetros etológicos seleccionados. Se concluye que la actividad natatoria y la ubicación espacial de las especies estudiadas, entre otros indicadores, pueden ser considerados como biomarcadores de toxicidad acuática

By means of an automatic recording device, the effects of the exposure to sublethal solutions of Cd2+ (0.3 mg. L ) on some ethological parameters of juvenile Cyprinus carpio (common carp) and Astyanax fasciatus. The effect of the metal was evaluated through three parameters: the total swimming activity and the spatial (lateral and altitudinal) preferences, relative to controls (fish kept in tap water); they were registered simultaneously by means of an original device. There were determined successively the “normal” or standard levels of those parameters in control fish and those reached by the same individuals after their exposure to the reference toxic (Cd). In both species the metal caused a depression of the total swimming activity in a comparable magnitude. The altitudinal preference was also modified: C. carpio was found more frequently in the superior layer of the aquaria while A. fasciatus was found in the inferior ones. For the lateral preference, the individuals of both species showed an avoidance behavior of the site of the aquaria where the Cd solutions was dripping. This response of the animals didn t follow a defined pattern, but was more marked in the carps. All the evaluated responses to the toxic were detected immediately after the beginning of the exposure to Cd. The method proved to be sensitive and apt for the monitoring of the measured behavioural parameters which makes it a promising tool for biomonitoring purposes. We concluded that the swimming activity and the spatial location preferences of the studied species, among other, may be considered as biomarkers of aquatic toxicity