Fauna endoparasit?ria de Metynnis lippincottianus (Cope, 1870) do Alto Rio S?o Francisco, Minas Gerais, Brasil

• Autor(a) principal: Berto, Maria de F?tima Cancella Almeida
• Data de Publicação: 2018
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UFRRJ
• Texto Completo: https://tede.ufrrj.br/jspui/handle/jspui/4901
• topic: Metynnis lippincottianus; Nematoda; Platyhelminthes; Parasitologia; Medicina Veterin?ria

Metynnis lippincottianus (Cope, 1870) is a freshwater fish commonly known as ?pacu?or ?pacu-marreca?, pelagic, reaches the total length of 20 cm and sexual maturation around 10 cm. The pacu feed on aquatic vegetables, fruits, seeds, phytoplanktonic algae, arthropods and debris. This fish originates from the Amazon River basin and northeast rivers of the French Guiana. The current work aimed: identify the species of the endoparasitary fauna of Metynnis lippincottianus of the upper S?o Francisco River, Minas Gerais, Brazil; record the parasite parameters and the infection sites of each parasite; provide the morphometric and morphological data of the parasite species; identify possible correlations between parasite parameters, total length and host sex; investigate ecological interactions of the hosts based on the interpretation of possible biological cycles of the parasites; and compare the fauna found with the records of these parasites in native hosts of the water system and in other hosts of other localities, to evaluate a possible parasite and host specificity and to contribute to the identification of parasite species that could be simultaneously introduced into the biotic community of the upper S?o Francisco River system. In June and October 2016, a total of 67 specimens of Metynnis lippincottianus were collected by local fishermen at the mouth of Borrachudo, upstream of the Tr?s Marias dam, Alto Rio S?o Francisco, Tr?s Marias Municipality, State of Minas Gerais, Brazil, and examined at the Laborat?rio de Biologia e Ecologia Parasit?ria of the Universidade Federal Rural do Rio de Janeiro. The collected endoparasites were studied according to the methodology used in Ichthychoasitology. Of the 67 fish analyzed, 63 were parasitized, and five species of parasites were found. Among the Platyhelminthes, in the posterior gut of the fish was found a specimen of Digenea, Dadayius sp. and plerocercoid larvae (Eucestoda, Proteocephalidae) in the peritoneal cavity, adhered to the surface of the stomach and intestines of the host. Among the Nematoda were found Procamallanus (Spirocamallanus) inopinatus Travassos, Artigas & Pereira, 1928 in the stomach and the anterior intestine of the host, Spinitectus rodolphiheringi Vaz & Pereira, and Spinoxyuris sp. in the host's posterior intestine. In the analysis of the parasite indices in relation to the size of the male and female fish, the intensity and abundance of Spinoxyuris sp. were higher only in the smaller male fish. This parasites in Metynnis lippincottianus in the S?o Francisco River are unrecorded in the scientific literature. The presence of plerocercoid larvae and the Spinitectus rodolphiheringi nematode characterize new findings and increase the composition of the known parasitic fauna of Metynnis spp. in relation to the parasitic fauna recorded in congeneric species of other basins. In addition, Dadayius sp. and Spinoxyuris sp. are parasites registered for the first time in the S?o Francisco basin. Metynnis lippincottianus, fish of recent introduction in the S?o Francisco basin, has acquired parasites and is acting as a paratenic, intermediate and definitive host of these species of helminths.