Blood cell alterations in Colossoma macropomum juveniles caused by silver nanoparticles.

This study evaluated the median lethal concentration of silver nanoparticles and their effects in fish tambaqui Colossoma macropomum. Therefore, an acute toxicity assay was carried out in completely randomized design evaluating six different concentrations of silver nanoparticles on blood parameters of tambaqui. The silver nanoparticles were produced by chemical reduction with polyvinyl alcohol (AgNP-PVA). The lethal concentration 50% (LC50) was estimated using probit regression. The blood was collected, analyzed and the data were submitted to T-test (dying x surviving fish) and Tukey test (surviving fish). An increase in glucose, hematocrit, total plasma protein, hemoglobin, erythrocytes, leukocytes, monocytes, and neutrophils as well as reduced MCV (mean corpuscular volume) in dying fish compared to surviving fish were observed. Survived fish exposed to 187.5 µg/L showed an increase in hematocrit, MCV, and MCH and a reduction in erythrocytes, total numbers of leukocyte, thrombocyte, lymphocyte, and neutrophil. The fish exposed to concentrations below 125 µg/L, had returned the blood parameter to baselines compared to control. The estimated LC50 was 165.09 µg/L and was classified as highly toxic for the fish tambaqui. In higher concentrations, it causes an acute respiratory toxicity, but in concentrations below 125 µg/L, the fish can adapt to the stressing agent.

Deltamethrin-induced nuclear erythrocyte alteration and damage to the gills and liver of Colossoma macropomum.

Deltamethrin is one of the most commonly used pyrethroids in the world, and it has a high toxic potential, mainly on aquatic organism. Thus, the purpose of this study was to evaluate LC50 values of deltamethrin on tambaqui (Colossoma macropomum) fingerlings and to investigate genotoxic effects and histopathological responses. Fish were exposed to different concentrations of deltamethrin (0, 6.16 × 10-3; 6.44 × 10-2; 1.34 × 10-1, and 1.93 × 10-1 mg L-1) for 96 h. In addition, a genotoxicity analysis was carried out on peripheral blood erythrocytes and histopathological changes were classified by the severity degree of damage and organ functioning. The 96 h LC50 value for tambaqui was estimated at 5.56 × 10-2 mg L-1 using a static test system. Nuclear abnormalities in exposed fish included micronuclei, blebbed, notched, 8-shaped, and binucleated nuclei forms. Deltamethrin significantly induced a notched nucleus compared to other abnormalities. A histopathological examination showed hepatic lesions and gill damage. Deltamethrin was found to be highly toxic; it induced genotoxicity and caused liver and gill inflammation in tambaqui.

Alterações leucocitárias ocasionadas pelo estresse toxicológico agudo do óleo diesel em juvenis de tilápia-do-nilo / Change in leukocyte by acute toxicological stress of diesel oil in juveniles of Nile tilapia

O presente trabalho teve como objetivo avaliar o estresse e as alterações no leucograma dos juvenis de Oreochromis niloticus submetidos à toxicidade aguda do óleo diesel. A toxicidade foi avaliada em um delineamento inteiramente casualizado com cinco diluições (20, 25, 30, 35 e 40%) e um controle, ambos com três repetições. Para a avaliação dos níveis glicêmicos e alteração no leucograma, foi retirado sangue por punção caudal dos peixes moribundos. Dessa forma, conclui-se que o óleo diesel pode apresentar riscos ao ecossistema aquático, provocando toxicidade aos organismos aquáticos e alterações fisiológicas.(AU)

This study aimed to evaluate the stress and changes in white blood cell count of juveniles Oreochromis niloticus subjected to acute toxicity of diesel oil. The toxicity was evaluated in a completely randomized design with five dilutions (20, 25, 30, 35 and 40%) and one control, both with three replicates. For the assessment of blood glucose levels and changes in white blood cell count, blood was drawn by caudal puncture of the dying fish. It was concluded that diesel oil can present risks to aquatic ecosystem, causing toxicity and physiological changes to fish.(AU)