RESUMO
Pantanal shrimp Macrobrachium pantanalense was exposed for 96 h to the cypermethrin-based formulation Barrage®. Population-relevant endpoints (survival, swimming behavior) as well as histopathology of gills were analyzed. A 96 h-LC50 of 0.93 µg/L of cypermethrin was calculated while equilibrium disturbances were observed at 1.25 µg/L. Histological examination showed predominantly regressive changes in the gills of shrimp exposed to concentrations of 0.25 and 1.25 µg/L. Three levels of lesions were observed in the gills: I- Intercellular edema, epithelial lifting of the lamellae and lamellar fusion, fat vacuoles and hypertrophy of gill epithelial cells or mucous cells; II- nuclear changes, atrophy (reduction of volume and number) and hyperplasia of gill epithelia and III- necrosis. This study shows the high sensitivity of the shrimp M. pantanalense to the pesticide Barrage® highlighting the importance of monitoring agrochemicals residues in the Pantanal region (Brazil) and conduct risk evaluation studies to prevent deleterious effects on the aquatic communities of Pantanal.
Assuntos
Brânquias/efeitos dos fármacos , Inseticidas/toxicidade , Palaemonidae/efeitos dos fármacos , Piretrinas/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Brânquias/patologiaRESUMO
The aim of this study was to determine the morphometric measures and morphological aspects of nematode-cysts in Gymnotus inaequilabiatus, and the presence of melanomacrophage centers (MMCs) associated with the periphery of cysts and in the liver parenchyma. Adult specimens, 34 female (123.1 ± 43.9g) and 45 male (135.5 ± 43.4g), from Paraguay River, Corumbá, Brazil, were used. The number of nematode-cysts was determined in 79 livers and 25 of them randomly selected for histopathological analysis and morphometric measures of nematode-cysts (mean diameter, thickness of collagen layer, and cyst-wall layer). The percentage of cysts with MMCs on the periphery and density in the liver parenchyma was estimated. The average number of macroscopic cysts was of 48.7 ± 2.78. Granulomatous reaction was observed surrounding the cysts. Diameter, collagen layer and cyst-wall measurements were 293.0 ± 75.18 (µm), 17.72 ± 6.01 (µm) and 12.21 ± 9.51 (µm), respectively. The number of nematode-cysts was correlated with hepatosomatic index, (r=0.26, P<0.05). Collagen layer was correlated with cyst diameter (r=0.62, P<0.01). Pericystic and parenchymatous MMCs were moderately (r=0.48) and highly (r=0.90) correlated with nematode-cysts number. Morphological characteristics of hepatic tissue and cysts-nematodes measures suggest that G. inaequilabiatus acts as a paratenic host to nematodes in the larval stage.
Assuntos
Gimnotiformes/parasitologia , Fígado/parasitologia , Nematoides/anatomia & histologia , Animais , Brasil , Áreas AlagadasRESUMO
Abstract The aim of this study was to determine the morphometric measures and morphological aspects of nematode-cysts in Gymnotus inaequilabiatus, and the presence of melanomacrophage centers (MMCs) associated with the periphery of cysts and in the liver parenchyma. Adult specimens, 34 female (123.1 ± 43.9g) and 45 male (135.5 ± 43.4g), from Paraguay River, Corumbá, Brazil, were used. The number of nematode-cysts was determined in 79 livers and 25 of them randomly selected for histopathological analysis and morphometric measures of nematode-cysts (mean diameter, thickness of collagen layer, and cyst-wall layer). The percentage of cysts with MMCs on the periphery and density in the liver parenchyma was estimated. The average number of macroscopic cysts was of 48.7 ± 2.78. Granulomatous reaction was observed surrounding the cysts. Diameter, collagen layer and cyst-wall measurements were 293.0 ± 75.18 (µm), 17.72 ± 6.01 (µm) and 12.21 ± 9.51 (µm), respectively. The number of nematode-cysts was correlated with hepatosomatic index, (r=0.26, P<0.05). Collagen layer was correlated with cyst diameter (r=0.62, P<0.01). Pericystic and parenchymatous MMCs were moderately (r=0.48) and highly (r=0.90) correlated with nematode-cysts number. Morphological characteristics of hepatic tissue and cysts-nematodes measures suggest that G. inaequilabiatus acts as a paratenic host to nematodes in the larval stage.
Resumo O objetivo deste estudo foi determinar as características morfológicas e morfométricas de cistos de nematodas em fígado de Gymnotus inaequilabiatus, e a presença de centros de melanomacrófagos (CMMs) pericísticos e no parênquima hepático. Espécimes adultos, 34 fêmeas (123,1 ± 43,9 g) e 45 machos (135,5 ± 43,4g), provenientes do Rio Paraguai, Corumbá, Brasil foram utilizados. Os cistos foram quantificados em 79 fígados. Em 25 fígados foi realizada a análise histopatológica e morfometria dos cistos (diâmetro, espessura da camada de colágeno e da parede). Estimou-se a porcentagem de cistos com CMMs periférico e a densidade de CMMs no parênquima. A média de cistos macroscópicos foi de 48,7 ± 2,78. Observou-se reação granulomatosa pericística. O diâmetro, a espessura da camada de colágeno e da parede do cisto foi de 293,0 ± 75,18 (µm), 17,72 ± 6,01 (µm) e 12,21 ± 9,51 (µm), respectivamente. O número de cistos foi associado ao índice hepatossomático, (r=0,26, P <0,05). A camada de colágeno correlacionou-se com o diâmetro do cisto (r=0,62, P <0,01). CMMs pericísticos e do parênquima apresentaram correlação moderada (r=0,48) e alta (r=0,90) com o número de cistos, respectivamente. As características morfológicas do tecido hepático e a morfometria dos cistos de nematodas sugerem que G. inaequilabiatus atua como hospedeiro paratênico para larvas de nematodas.
Assuntos
Animais , Gimnotiformes/parasitologia , Fígado/parasitologia , Nematoides/anatomia & histologia , Brasil , Áreas AlagadasRESUMO
The aim of this study was to determine the morphometric measures and morphological aspects of nematode-cysts in Gymnotus inaequilabiatus, and the presence of melanomacrophage centers (MMCs) associated with the periphery of cysts and in the liver parenchyma. Adult specimens, 34 female (123.1 ± 43.9g) and 45 male (135.5 ± 43.4g), from Paraguay River, Corumbá, Brazil, were used. The number of nematode-cysts was determined in 79 livers and 25 of them randomly selected for histopathological analysis and morphometric measures of nematode-cysts (mean diameter, thickness of collagen layer, and cyst-wall layer). The percentage of cysts with MMCs on the periphery and density in the liver parenchyma was estimated. The average number of macroscopic cysts was of 48.7 ± 2.78. Granulomatous reaction was observed surrounding the cysts. Diameter, collagen layer and cyst-wall measurements were 293.0 ± 75.18 (µm), 17.72 ± 6.01 (µm) and 12.21 ± 9.51 (µm), respectively. The number of nematode-cysts was correlated with hepatosomatic index, (r=0.26, P 0.05). Collagen layer was correlated with cyst diameter (r=0.62, P 0.01). Pericystic and parenchymatous MMCs were moderately (r=0.48) and highly (r=0.90) correlated with nematode-cysts number. Morphological characteristics of hepatic tissue and cysts-nematodes measures suggest that G. inaequilabiatus acts as a paratenic host to nematodes in the larval stage.(AU)
O objetivo deste estudo foi determinar as características morfológicas e morfométricas de cistos de nematodas em fígado de Gymnotus inaequilabiatus, e a presença de centros de melanomacrófagos (CMMs) pericísticos e no parênquima hepático. Espécimes adultos, 34 fêmeas (123,1 ± 43,9 g) e 45 machos (135,5 ± 43,4g), provenientes do Rio Paraguai, Corumbá, Brasil foram utilizados. Os cistos foram quantificados em 79 fígados. Em 25 fígados foi realizada a análise histopatológica e morfometria dos cistos (diâmetro, espessura da camada de colágeno e da parede). Estimou-se a porcentagem de cistos com CMMs periférico e a densidade de CMMs no parênquima. A média de cistos macroscópicos foi de 48,7 ± 2,78. Observou-se reação granulomatosa pericística. O diâmetro, a espessura da camada de colágeno e da parede do cisto foi de 293,0 ± 75,18 (µm), 17,72 ± 6,01 (µm) e 12,21 ± 9,51 (µm), respectivamente. O número de cistos foi associado ao índice hepatossomático, (r=0,26, P 0,05). A camada de colágeno correlacionou-se com o diâmetro do cisto (r=0,62, P 0,01). CMMs pericísticos e do parênquima apresentaram correlação moderada (r=0,48) e alta (r=0,90) com o número de cistos, respectivamente. As características morfológicas do tecido hepático e a morfometria dos cistos de nematodas sugerem que G. inaequilabiatus atua como hospedeiro paratênico para larvas de nematodas.(AU)