Susceptibility to monogenetic parasites in Serrasalminídeo

The development of activities related to aquaculture has considerably increased the relevance of studies on parasites and other pathogens of aquatic organisms, especially those with potential for cultivation and commercialization. The objective of this study was to evaluate the susceptibility and occurrence of monogenetic infections in Colossoma macropomum, Piaractus mesopotamicus, Piaractus brachypomus and their hybrids. The animals were cultivated for 10 months in a closed recirculation system. After this period they were slaughtered and necropsies performed with total removal of the gills. These were fresh analyzed and positive for monogenetics were fixed in 10% formaldehyde. The monogenetics present in the gills of each fish were quantified and submitted to the preparation of slides to identify the genera. For identification, sclerotized structures were observed, such as hooks, anchors, haptor bars and copulatory complex; important in identifying the genera and species of this group. Based on the quantification, parasitism intensity and parasite occurrence were established. No fish collected showed clinical signs of parasitic infections. During the parasitological analysis of the gills two genera of monogenetics Anacanthorus sp. and Mymarothecium sp. For Anacanthorus sp. Piaractus mesopotamicus species, pirapicu hybrids and post F1 animals were the most resistant animals. For Mymarothecium sp. pacu species and all hybrids showed resistance