Astronotus crassipinnis

Abstract: The aquatic habitats of the Amazon basin present dramatic variation of oxygen level, and, to survive such changes, many aquatic animals developed biochemical and physiological adaptations. The advanced teleost Astronotus crassipinnis (Perciformes) is a fish tolerant to hypoxia and known to endure such naturally variable environments. Hypoxia-Inducible factor-1α (hif-1α) is among the most important and studied genes related to hypoxia-tolerance, maintaining regular cellular function and controlling anaerobic metabolism. In the present work, we studied hif-1α expression and related it to changes in metabolic pathways of Astronotus crassipinnis exposed to 1, 3 and 5 h of hypoxia, followed by 3 h of recovery. The results show that A. crassipinnis depresses aerobic metabolic under hypoxia, with a decrease in glycolysis and oxidative enzyme activities, and increases its anaerobic metabolism with an increase in LDH activity coupled with a decrease in oxygen consumption, which indicates an increase in anaerobic capacity. In addition, the animal differentially regulates hif-1α gene in each tissue studied, with a positive relationship to its metabolic profile, suggesting that hif-1α might be one of the most important induction factors that regulate hypoxia tolerance in this species.

Abstract: We provide the first study on the diversity and community of parasites in Astronotus crassipinnis from the lower Amazon River, in Brazil. Of 35 hosts examined, 100% were infected with one or more species of parasites, such as Gussevia asota, Gussevia astronoti, Gussevia rogersi, Posthodiplostomum sp., Contracaecum sp., Gorytocephalus sp. and Dolops longicauda. Gussevia asota, G. astronoti and G. rogersi were dominant, and, in total, 9788 parasites were collected. The richness of parasite species (4.9±0.7), Brillouin diversity (0.46±0.28) and evenness (0.29±0.17) were low. Parasites had aggregated dispersion, parasitism did not affect the host condition factor, and host size did not influence abundance, species richness and parasite diversity. The parasitic fauna was characterized by the presence of few species of parasites with high prevalence and low abundance, specifically the endoparasites, besides dominance of ectoparasites. The presence of endoparasites indicates that the diet of A. crassipinnis consists mostly of mollusks and microcrustaceans. This fish species is an intermediate host for Posthodiplostomum sp., Contracaecum sp. and Gorytocephalus sp., parasites found in larval stage. Finally, the behavior and availability of infective stages, which are intermediate hosts for endoparasites, were factors structuring the communities of endoparasites.

Abstract: The aquatic habitats of the Amazon basin present dramatic variation of oxygen level, and, to survive such changes, many aquatic animals developed biochemical and physiological adaptations. The advanced teleost Astronotus crassipinnis (Perciformes) is a fish tolerant to hypoxia and known to endure such naturally variable environments. Hypoxia-Inducible factor-1α (hif-1α) is among the most important and studied genes related to hypoxia-tolerance, maintaining regular cellular function and controlling anaerobic metabolism. In the present work, we studied hif-1α expression and related it to changes in metabolic pathways of Astronotus crassipinnis exposed to 1, 3 and 5 h of hypoxia, followed by 3 h of recovery. The results show that A. crassipinnis depresses aerobic metabolic under hypoxia, with a decrease in glycolysis and oxidative enzyme activities, and increases its anaerobic metabolism with an increase in LDH activity coupled with a decrease in oxygen consumption, which indicates an increase in anaerobic capacity. In addition, the animal differentially regulates hif-1α gene in each tissue studied, with a positive relationship to its metabolic profile, suggesting that hif-1α might be one of the most important induction factors that regulate hypoxia tolerance in this species.

Abstract: In comparison with the Bolivian Amazon, the ichthyofauna of the La Plata drainage of Bolivia received relatively little attention historically. Until now, 14 species of cichlid fish have been registered from this area. After an exhaustive review of museum collections (Museo de Historia Natural Noel Kempff Mercado y Coleccion Boliviana de Fauna), we can report three additional species: Astronotus crassipinnis (Heckel, 1840), Mesonauta festivus (Heckel, 1840) and Satanoperca pappaterra (Heckel, 1840). Four other species, which have been listed in previous publications, can be confirmed for the La Plata drainage of Bolivia based on the examination of voucher specimens: Aequidens plagiozonatusKullander, 1984, Apistogramma commbrae (Regan, 1906), A. trifasciata (Eigenmann & Kennedy, 1903) and Crenicichla vittata Heckel, 1840. As such, 16 of the 17 species can be referenced with voucher specimens in museum collections. We also provide an identification key for the cichlid fish species of the study area.

Abstract: In comparison with the Bolivian Amazon, the ichthyofauna of the La Plata drainage of Bolivia received relatively little attention historically. Until now, 14 species of cichlid fish have been registered from this area. After an exhaustive review of museum collections (Museo de Historia Natural Noel Kempff Mercado y Coleccion Boliviana de Fauna), we can report three additional species: Astronotus crassipinnis (Heckel, 1840), Mesonauta festivus (Heckel, 1840) and Satanoperca pappaterra (Heckel, 1840). Four other species, which have been listed in previous publications, can be confirmed for the La Plata drainage of Bolivia based on the examination of voucher specimens: Aequidens plagiozonatusKullander, 1984, Apistogramma commbrae (Regan, 1906), A. trifasciata (Eigenmann & Kennedy, 1903) and Crenicichla vittata Heckel, 1840. As such, 16 of the 17 species can be referenced with voucher specimens in museum collections. We also provide an identification key for the cichlid fish species of the study area.