Parasitos em trutas-arco-íris (Oncorhynchus mykiss) criadas em sistema intensivo na região serrana de Santa Catarina, Brasil / [Parasites in rainbow trout (Oncorhynchus mykiss) raised in an intensive system in the mountain region of Santa Catarina, Brazil]

With the aim to determine the prevalence and mean parasite intensity in Oncorhynchus mykiss, 120 specimens were analyzed between April and September 2018. The cavity analysis was done by visual inspection, scraping of mucus, and extraction of the branchial arches. In the evisceration process, the intestine, the liver, and the kidney were separated, while the musculature was analyzed using the "candling table" method. All the collected material was preserved in 10% buffered formaldehyde and sent to the Laboratory of Parasitology and Parasitic Diseases, of the Center for Agroveterinary Sciences (CAV) of the University of the State of Santa Catarina (UDESC) for making the slides and identifying the parasites. Parasites were detected only in the analysis of the scraping of body mucus. Only specimens of the genus Trichodina were identified, in 34 of the 120 fish analyzed, in two collections, resulting in a prevalence of 28.33%. In total, 144 specimens of Trichodina were observed. The overall mean intensity was of 4.24 parasites in each fish analyzed. Characteristic lesions of infection by protozoa were not identified. This is the first report of the occurrence of Trichodina spp. in O. mykiss bred in an intensive system in Brazil, with low rates of parasitic infection in the mountain region of Santa Catarina.(AU)

Efecto in vitro del suero de la trucha arco iris, oncorhynchus mykiss, sobre metacercarias del género tylodelphys trematoda displostomatidae / The in vitro effect of rainbow trout, oncorhynchus mykiss, serum in tylodelphys sp trematoda displostomatidae metacercariae

Here, it has been described that normal fresh sera from rainbow trout (oncorhynchus mykiss) were able to Iyse Tylodlphys sp. metacercariae isolated form Galaxias maculatus (Jenyns, 1842) (Teleostei, Galaxiidae) brain. This effect was time dependent, and progressively increased since 1 h up to 18 h incubation. There were oscillations in the ability of different sera samples to lyse these parasites. Similar values were achieved with other salmonid sera, and also with normal human sera pool. The lytic activity was abolished by heat-inactivated sera, by zymosan treatment and by incubation in the presence of EDTA. However, the mean values obtained in the presence of EGTA-Mg++ did not significantly differ from those found with sera as a source of complement. The results of this study suggested the role of complement alternative pathway on Tylodephys sp. in vitro lysis, under our experimental conditions

Control de saprolégniales por acido acético, cloruro de sodio y verde malaquita en huevos de trucha arcoiris / Saprolegniales control by acetic acid, sodium chloride and malaquite green in eggs of rainbow trout

Con la finalidad de determinar la eficacia, como agentes inhibidores del crecimiento fúngico de saprolegniales en ovas de trucha arcoiris, se procedió a la evaluación de tratamientos con ácido acético (100 ppm, 300ppm y 500ppm), cloruro de sodio (20 porciento) y verde malaquita (2,5 ppm). Los parámetros medios fueron: la mortalidad total de los huevos hasta que éstos presentaron el ojo visible y la deformidad de alevines con saco. Los tratamientos se aplicaron utilizándo la técnica de corte de flujo, efectuada día por medio y con tiempos de 60 minutos de duración. Este procedimiento abarcó desde la fecundación hasta la aparición de los ojos. El verde malaquita, presentó la menor mortalidad total de huevos (12,95 porciento), seguido por el ácido acético a 500 ppm (16,96 porciento). En las ovas muertas con hongos adheridos a su superficie se registró un 6,76 porciento para verde malaquita y un 11,72 porciento para el ácido acético a 500 ppm. Con el cloruro de sodio se obtuvo la mayor proporción en ambos casos. Los huevos tratados con verde de malaquita, registraron una alta incidencia de alevines con saco deformes (13,5 porciento), mientras para los restantes tratamientos, fueron inferiores al 7 porciento. Es posible concluir que el ácido acético en concentraciones de 500 ppm puede ser utilizado como sustituto al verde malaquita para controlar infecciones micóticas en ovas, ya que no produce elevados niveles de mortalidad en los huevos y no induce a la formación de alevines con saco deformes