Influência do manejo reprodutivo e da despesca na saúde de Astyanax altiparanae
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Data
2020-02-18
Autores
Norquis Caled, Alvarez Rubio
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A produção de lambaris (Astyanax sp.) tem destaque na piscicultura de peixes nativos no Brasil devido ao crescente uso como isca viva e consumo direto como petisco. As pesquisas nesta espécie ainda são insipientes, particularmente na área da sanidade. Relatos de casos e diagnósticos laboratoriais sugerem que a aeromoniose é a principal doença infecciosa nesta espécie. O presente trabalho teve como objetivo avaliar o papel de diversos fatores de manejo reprodutivo e da despesca na susceptibilidade de Astyanax altiparanae à infecção experimental por Aeromonas hydrophila pelo método de banhos de imersão. Foram avaliados o material das redes de despesca, o sexo, a reversão sexual, a temperatura e o pH da água. A infecção experimental foi induzida por imersão em solução diluída de uma cepa patógena de A. hydrophila. Os sinais clínicos, lesões anatomopatológicas, integridade da pele e a mortalidade foram avaliados durante 12 dias. Com respeito ao uso de diferentes tipos de rede de despesca, a sobrevivência foi significativamente menor e houve severas lesões cutâneas na pele dos peixes manipulados com rede de nylon quando comparados aos grupos com redes de polipropileno, polietileno ou peixes manejados sem rede. Por outro lado, a reversão sexual com estradiol evidenciou sobrevivência menor das fêmeas sobre os machos (ambos tratados com hormônios), e houve tendência ao incremento na mortalidade com a adição do hormônio na ração (2 vs 4 mgkg-1 ). Com relação à temperatura e o pH da água, registrou-se menor sobrevivência nos grupos mantidos nas temperaturas e pH mais altos. Conclui-se que o método de imersão mostrou-se adequado para reproduzir a infecção com A. 2 hydrophila no lambari de rabo amarelo e que diversos fatores de manejo influenciaram o curso da infecção.
Yellowtail tetra (Astyanax sp) production has a promissory future in native fish farming in Brazil due to the increased use of this species as live bait and for direct consumption. Research on this species is still incipient, particularly in aquatic health, where local reports suggest that aeromoniosis is the major infectious diseases in yellowtail tetra. The present work aimed to evaluate the role of several reproductive and handling factors on the susceptibility of Astyanax altiparanae to experimental infection with Aeromonas hydrophila by an immersion bath method. The effects of the net material used for handling, sex, sexual reversion, water temperature and pH were evaluated. Experimental infection was achieved by immersion in dilute solution of a pathogenic strain of A. hydrophila. Clinical signs, pathological lesions, skin integrity and mortality were evaluated for 12 days. Regarding the different types of net material, the study showed significant lower survival and more severe cutaneous lesions in fish manipulated with nylon net when compared to polypropylene, polyethylene net and managed by hand. In addition, sexual reversion with estradiol revealed lower survival for females over males (both treated with hormones), and there was a tendency to increased mortality rates with the incorporation of hormone in the diet. Regarding water temperature and pH, there was lower survival in the groups maintained at higher temperature and pH. It was concluded that the immersion bath method is a suitable model to reproduce A. hydrophila infection 3 in the yellowtail tetra and that several factors such as the net material, sex, water temperature and pH influence the course of the infection.
Yellowtail tetra (Astyanax sp) production has a promissory future in native fish farming in Brazil due to the increased use of this species as live bait and for direct consumption. Research on this species is still incipient, particularly in aquatic health, where local reports suggest that aeromoniosis is the major infectious diseases in yellowtail tetra. The present work aimed to evaluate the role of several reproductive and handling factors on the susceptibility of Astyanax altiparanae to experimental infection with Aeromonas hydrophila by an immersion bath method. The effects of the net material used for handling, sex, sexual reversion, water temperature and pH were evaluated. Experimental infection was achieved by immersion in dilute solution of a pathogenic strain of A. hydrophila. Clinical signs, pathological lesions, skin integrity and mortality were evaluated for 12 days. Regarding the different types of net material, the study showed significant lower survival and more severe cutaneous lesions in fish manipulated with nylon net when compared to polypropylene, polyethylene net and managed by hand. In addition, sexual reversion with estradiol revealed lower survival for females over males (both treated with hormones), and there was a tendency to increased mortality rates with the incorporation of hormone in the diet. Regarding water temperature and pH, there was lower survival in the groups maintained at higher temperature and pH. It was concluded that the immersion bath method is a suitable model to reproduce A. hydrophila infection 3 in the yellowtail tetra and that several factors such as the net material, sex, water temperature and pH influence the course of the infection.
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Palavras-chave
Lambaris, Septicemia hemorrágica, Aeromonose, Sanidade aquícola