Acute toxicity and histopathologic effects of diquat herbicide on the gill and liver of Nile tilapia (Oreochromis niloticus)

Made available in DSpace on 2013-09-27T16:24:27Z (GMT). No. of bitstreams: 1 ZOORECZOOR14411070488.pdf: 207351 bytes, checksum: 8a7aed0812ad2ec9417a174f6fec915d (MD5) Previous issue date: 2008-01-01 Made available in DSpace on 2013-09-30T17:50:24Z (GMT). No. of bitstreams: 1 ZOORECZOOR14411070488.pdf: 207351 bytes, checksum: 8a7aed0812ad2ec9417a174f6fec915d (MD5) Previous issue date: 2008-01-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T13:13:28Z No. of bitstreams: 1 ZOORECZOOR14411070488.pdf: 207351 bytes, checksum: 8a7aed0812ad2ec9417a174f6fec915d (MD5) Made available in DSpace on 2014-05-20T13:13:28Z (GMT). No. of bitstreams: 1 ZOORECZOOR14411070488.pdf: 207351 bytes, checksum: 8a7aed0812ad2ec9417a174f6fec915d (MD5) Previous issue date: 2008-01-01 The lethal concentration of 50% (LC (I) and the histopathologic effects of diquat herbicide on Nile tilapia (Oreochromis niloticus) fish were evaluated in three experiments. The fishes were exposed to concentrations of 0, 25, 30, 35, 40, 45, 50, 55 and 60 rug diquat L-1, and gill and liver histology were evaluated in the surviving fishes. The estimated LC (I) (50-96h) of diquat was 37.28 mg L-1, with lower limits of 33.12 mg L-1 and upper limits of 41.44 mg L-1. In the treatment with 30, 35 and 40 mg L-1, signs of apical fusion of the secondary lamellae were observed; with 45 and 50 mg L-1, congestion of the primary lamellae was observed; in the treatment with 55 mg L-1, congestion of blood vessels on secondary lamellae took place. The livers of fishes in treatments with 0, 25, 30 and 35 mg L-1showed cordonal organization of hepatocytes. In the treatments with 40 and 45 mg L-1, hypertrophy of hepatocytes took place; with 50 and 55 mg L-1, cell fusion and the presence of vacuoles inside hepatocytes were observed. Diquat presented low risk of toxicity for nile tilapia, as the more severe histopathologic alterations occurred only in higher concentrations. Nucleo de Estudos e Pesquisas Ambientais em Matologia, Departamento de Biologia Aplicada a Agropecuaria, Universidade Estadual Paulista, Via de Acesso Paulo Donato Castelanni, s/n, 14884-900, Jaboticabal, São Paulo Nucleo de Estudos e Pesquisas Ambientais em Matologia, Departamento de Biologia Aplicada a Agropecuaria, Universidade Estadual Paulista, Via de Acesso Paulo Donato Castelanni, s/n, 14884-900, Jaboticabal, São Paulo