Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 18 de 18
Filtrar
Mais filtros











Intervalo de ano de publicação
1.
Toxicon ; 231: 107201, 2023 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-37336392

RESUMO

This study aims to update the knowledge concerning the intoxication by Tephrosia noctiflora in Brazilian cattle herds by reporting new cases of intoxication in lactating cows, their calves and bulls and highlight the epidemiology, clinical signs, pathogenesis, gross, and microscopic lesions. The morbidity and mortality of this intoxication in the farms studied was low. Gross lesions in all affected cattle consisted of dermatitis with hyperpigmentation, crusts, ulceration, erythema, and lichenification in the skin of limbs, ventral abdomen, perianal and perineal areas of lactating calves and adult cattle. Microscopically, the main lesion observed consisted of severe dermatitis with parakeratotic hyperkeratosis, papillated proliferation, and diffuse, accentuated lymphoplasmacytic inflammatory infiltrate in the epidermis and dermis. The presence of skin lesions mainly in the limbs and ventral abdomen of cattle implies the pathogenesis of intoxication is related to a primary contact dermatitis, and the occurrence of similar lesions on the skin of nursing calves reinforces this hypothesis. The putative toxins of T. noctiflora have been thought to be rotenoids. Additional work is needed to define better if these compounds are the main toxin responsible for the dermatopathy observed in these herds.


Assuntos
Doenças dos Bovinos , Dermatite , Tephrosia , Feminino , Animais , Bovinos , Masculino , Lactação , Doenças dos Bovinos/induzido quimicamente , Doenças dos Bovinos/epidemiologia , Brasil/epidemiologia , Dermatite/complicações , Dermatite/epidemiologia , Dermatite/veterinária , Surtos de Doenças/veterinária
2.
PLoS One ; 18(1): e0275835, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36630475

RESUMO

An increase in the incidence of arboviral, microbial and parasitic infections, and to disorders related to oxidative stress has encouraged the development of adjuvant therapies based on natural formulations, such as those involving plant extracts. Thus, to expand the repertoire of the available therapeutic options, this study aimed to describe the versatility of Tephrosia toxicaria (Sw.) (Pers., 1807) extracts for the control of arbovirus vectors, as well as their antioxidant, antileishmanial, and antimicrobial potential. Among the aqueous and hydroethanolic extracts obtained, the hydroethanolic extract from roots (RHA) was identified as the most active larvicide extract demonstrating, respectively, the lowest lethal concentration (mg/mL) for 50%, 90% and 99% of Aedes aegypti (L., 1762) and Aedes albopictus (S., 1894) larvae, observed at 24 h (0.33, 0.84 and 1.80; 0.32, 0.70 and 1.32) and 48 h (0.17, 0.51 and 1.22; 0.26, 0.47 and 0.78) post-exposure. Field assays revealed that RHA (0.84 mg/mL) is a potential oviposition deterrent, reducing egg-laying by approximately 90%. RHA (0.1 mg/mL) also exhibited antioxidant activity for the following tests: total antioxidant capacity (286.86 mg AAE/g), iron (87.16%) and copper (25.64%) chelation, and superoxide scavenging (10%). In the cell culture assays, RHA (0.1 mg/mL) promoted regeneration of metabolic activity (92% cell viability) in cells exposed to oxidative stress. Furthermore, RHA displayed weak antileishmanial activity (IC50 = 3.53 mg/mL) against Leishmania amazonensis and not exhibit antimicrobial activity. The extraction favored the concentration of carbohydrates in RHA, in addition to lectins and protease inhibitors, with molecular masses estimated between 10 and 24 kDa. Cytotoxicity and phytotoxicity analyses of RHA suggested its biosecurity. Thus, RHA is a multivalent extract with insecticide and antioxidant properties at low and safe concentrations. However, others studies on its indirect toxic effects are ongoing to ensure the complete safety of RHA.


Assuntos
Aedes , Anti-Infecciosos , Antiprotozoários , Tephrosia , Animais , Feminino , Antioxidantes/farmacologia , Mosquitos Vetores , Extratos Vegetais/toxicidade , Antiprotozoários/farmacologia , Anti-Infecciosos/farmacologia
3.
Toxicon ; 206: 21-27, 2022 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-34921844

RESUMO

An outbreak of a disease characterized by emaciation, dermatitis with erythema, alopecia, foul-smelling exudation, crusting, hyperpigmentation, lichenification, and edema of fore- and hindlimbs, chest and dewlap is described affecting cattle in the State of Alagoas, Northeastern Brazil. Microscopically, the main lesions were characterized by diffuse dermatitis with infiltration of lymphocytes, histiocytes, parakeratotic hyperkeratosis and acanthosis. The plant Tephrosia noctiflora, which exhibited signs of consumption, infested the grazing areas of cattle. To test its toxicity, T. noctiflora was harvested, dried in the shade, crushed and sourced at a concentration of 50% mixed with commercial food for three guinea pigs. The main clinical signs in guinea pigs included weight loss and multifocal, moderate to severe areas of alopecia, diffuse erythema of the skin, vaginal edema and hematuria. Microscopically, lymphocytic and histiocytic dermatitis, parakeratotic hyperkeratosis and acanthosis were noted in guinea pigs. This experiment confirms that T. noctiflora is the cause of outbreaks of dermatitis observed in cattle grazing in areas infested by this plant.


Assuntos
Doenças dos Bovinos , Tephrosia , Animais , Brasil , Bovinos , Doenças dos Bovinos/epidemiologia , Surtos de Doenças , Eritema/veterinária , Feminino , Cobaias , Pele , Tephrosia/toxicidade
4.
Pesqui. vet. bras ; 42: e07047, 2022. tab, ilus
Artigo em Inglês | VETINDEX | ID: biblio-1386831

RESUMO

Spontaneous and experimental poisoning by Tephrosia cinerea in the northeastern semiarid region of Brazil has only been described in sheep. Pathologically, such poisoning leads to ascites and centrilobular liver fibrosis. However, these effects require an experimental study in goats. This study aimed to determine the goats' susceptibility to the ingestion of T. cinerea and the minimum toxic dose, describing the main clinical and anatomopathological findings. Poisoning was reproduced experimentally in one sheep that received 10g/kg of the ground plant and in two goats, the first receiving a dose of 5g/kg and the second receiving 10g/kg of the ground plant. The sheep presented abdominal distension 34 days after beginning the ingestion of the plant, developing sternal decubitus, breathing difficulty, opisthotonos, mandibular trismus, salivation, dysphagia, vocalization, and pedaling movements on the 50th day of the experiment. Fluid accumulation was observed in the abdominal cavity and liver via necropsy, with an irregular, slightly whitish capsular surface. Histologically, the main lesions observed in the liver were moderate fibrosis, marked sinusoidal distension, accompanied by marked hemorrhage, sometimes forming bridges between the centrilobular regions, associated with a dissociation of hepatocyte cords. There were discrete Alzheimer's type II astrocytes in the gray matter in the region of the occipital cortex in the nervous system. Goat 2 showed apathy, drowsiness, and weight loss; on the 62th day, lateral decubitus evolved to sternal decubitus, with a rotation of the neck towards the flank. At necropsy, marked edema was observed on the face and dewlap, and a slight accumulation of liquid; slightly yellowish material was observed in the abdominal cavity. There were discrete blackened areas on the capsular surface in the liver. Histologically, the liver showed mild centrilobular fibrosis associated with mild dissociation of hepatocyte cords and mild vacuolar degeneration of the hepatocyte cytoplasm. Goat 1 showed no clinical signs; at necropsy, discrete multifocal areas were observed in the liver on the capsular surface. Histologically, diffuse intracytoplasmic vacuolar degeneration of hepatocytes was detected. The clinical picture and anatomopathological findings differ between the species, proving the lower susceptibility of goats to Tephrosia cinerea ingestion (compared to sheep), with differences in the pathogenesis and epidemiological aspects of poisoning.


A intoxicação espontânea e experimental por Tephrosia cinerea no semiárido nordestino só foi descrita em ovinos. Patologicamente, tal intoxicação leva a ascite e fibrose hepática centrolobular. No entanto, esses efeitos requerem um estudo experimental em caprinos. Este estudo teve como objetivo determinar a suscetibilidade de caprinos à ingestão de T. cinerea e a dose tóxica mínima, descrevendo os principais achados clínicos e anatomopatológicos. A intoxicação foi reproduzida experimentalmente em um ovino que recebeu 10g/kg da planta moída e em dois caprinos, o primeiro recebendo a dose de 5g/kg e o segundo recebendo 10g/kg da planta moída. O ovino apresentou distensão abdominal 34 dias após o início da ingestão da planta, desenvolvendo decúbito esternal, dificuldade respiratória, opistótono, trismo mandibular, salivação, disfagia, vocalização e movimentos de pedalada no 50º dia do experimento. Foi observado acúmulo de líquido na cavidade abdominal e fígado via necropsia, com superfície capsular irregular e levemente esbranquiçada. Histologicamente, as principais lesões observadas no fígado foram fibrose moderada, distensão sinusoidal acentuada, acompanhada de hemorragia acentuada, por vezes formando pontes entre as regiões centrolobulares, associada à dissociação dos cordões de hepatócitos. Havia discretos astrócitos de Alzheimer tipo II na substância cinzenta na região do córtex occipital no sistema nervoso. A cabra 2 apresentou apatia, sonolência e perda de peso; no 62º dia, decúbito lateral evoluiu para decúbito esternal, com rotação do pescoço em direção ao flanco. Na necropsia, observou-se edema acentuado na face e barbela, e leve acúmulo de líquido; foi observado material levemente amarelado na cavidade abdominal. Havia áreas enegrecidas discretas na superfície capsular no fígado. Histologicamente, o fígado apresentava leve fibrose centrolobular associada à discreta dissociação dos cordões de hepatócitos e leve degeneração vacuolar do citoplasma dos hepatócitos. A cabra 1 não apresentou sinais clínicos; na necropsia, discretas áreas multifocais foram observadas no fígado na superfície capsular. Histologicamente, foi detectada degeneração vacuolar intracitoplasmática difusa dos hepatócitos. O quadro clínico e os achados anatomopatológicos diferem entre as espécies, comprovando a menor suscetibilidade dos caprinos à ingestão de Tephrosia cinerea (em relação aos ovinos), com diferenças na patogênese e aspectos epidemiológicos da intoxicação.


Assuntos
Animais , Intoxicação por Plantas/veterinária , Cabras , Ovinos , Tephrosia/intoxicação , Tephrosia/toxicidade , Plantas Tóxicas
5.
Acta sci. vet. (Online) ; 47(suppl.1): Pub. 391, June 6, 2019. ilus, tab
Artigo em Português | VETINDEX | ID: vti-21088

RESUMO

Background: Tephrosia cinerea is a toxic plant responsible for liver fibrosis, which results in ascites and weight loss insheep and probably goats. Although T. cinerea is widespread in Brazil, reports of poisoning are described in the Eastern“Seridó” region of Rio Grande do Norte state, Central “Sertão” region of Ceará state, and “Sertão” of Paraíba state. Thus,this paper aimed to report clinical-epidemiological, laboratorial, pathological and ultrasonographic findings of sheepspontaneously poisoned by T. cinerea in the Western region of Rio Grande do Norte state, Northeastern Brazil.Cases: The evaluated cases occurred in sheep raised on properties located in the municipalities of Areia Branca and Tibau,Western region of Rio Grande do Norte state, Northeastern Brazil. In all visited farms, the pasture had a marked predominance of the T. cinerea. Clinical signs included progressive weight loss, dehydration, bilateral abdominal distension, andrespiratory dyspnea. Other less frequent clinical signs were hyporexia, pale mucosae, rough hair coat and polyuria. Hematology revealed leukocytosis by neutrophilia, while serum biochemical analysis revealed increased activities of GGTand ALT and reduced levels of total proteins, albumin and globulins. Abdominal ultrasonography was performed in onesheep, revealing a large amount of anechoic peritoneal effusion without floating echogenic debris or spots, and distentionof hepatic vessels and portal veins. Gross pathological findings included severe ascites, moderate hydrothorax and hydropericardium, and liver showing irregular nodular surface, whitish areas and hardened consistency. Microscopic evaluationof liver revealed hepatocyte necrosis, diffuse deposition of collagen fibers, and...(AU)


Assuntos
Animais , Tephrosia/toxicidade , Intoxicação por Plantas/veterinária , Ovinos , Plantas Tóxicas , Hepatopatias/diagnóstico , Cirrose Hepática/veterinária , Hepatopatias/veterinária
6.
Acta sci. vet. (Impr.) ; 47(suppl.1): Pub.391-2019. ilus, tab
Artigo em Português | VETINDEX | ID: biblio-1458155

RESUMO

Background: Tephrosia cinerea is a toxic plant responsible for liver fibrosis, which results in ascites and weight loss insheep and probably goats. Although T. cinerea is widespread in Brazil, reports of poisoning are described in the Eastern“Seridó” region of Rio Grande do Norte state, Central “Sertão” region of Ceará state, and “Sertão” of Paraíba state. Thus,this paper aimed to report clinical-epidemiological, laboratorial, pathological and ultrasonographic findings of sheepspontaneously poisoned by T. cinerea in the Western region of Rio Grande do Norte state, Northeastern Brazil.Cases: The evaluated cases occurred in sheep raised on properties located in the municipalities of Areia Branca and Tibau,Western region of Rio Grande do Norte state, Northeastern Brazil. In all visited farms, the pasture had a marked predominance of the T. cinerea. Clinical signs included progressive weight loss, dehydration, bilateral abdominal distension, andrespiratory dyspnea. Other less frequent clinical signs were hyporexia, pale mucosae, rough hair coat and polyuria. Hematology revealed leukocytosis by neutrophilia, while serum biochemical analysis revealed increased activities of GGTand ALT and reduced levels of total proteins, albumin and globulins. Abdominal ultrasonography was performed in onesheep, revealing a large amount of anechoic peritoneal effusion without floating echogenic debris or spots, and distentionof hepatic vessels and portal veins. Gross pathological findings included severe ascites, moderate hydrothorax and hydropericardium, and liver showing irregular nodular surface, whitish areas and hardened consistency. Microscopic evaluationof liver revealed hepatocyte necrosis, diffuse deposition of collagen fibers, and...


Assuntos
Animais , Cirrose Hepática/veterinária , Hepatopatias/diagnóstico , Intoxicação por Plantas/veterinária , Ovinos , Plantas Tóxicas , Tephrosia/toxicidade , Hepatopatias/veterinária
7.
Pesqui. vet. bras ; 38(4): 635-641, abr. 2018. tab, graf
Artigo em Português | LILACS, VETINDEX | ID: biblio-955396

RESUMO

A intoxicação por Tephrosia cinerea causa fibrose hepática periacinar em ovinos na região semiárida do Nordeste, com quadro clínico de ascite acentuada, e, ocasionalmente, com sinais neurológicos. Neste trabalho foram estudadas 16 ovinos em 6 surtos de intoxicação por T. cinerea. Todos os ovinos apresentaram lesões histológicas de fibrose periacinar e seis apresentaram, no encéfalo, vacuolização da substância branca e da junção entre a substância branca e a cinzenta com presença de astrócitos de Alzheimer tipo II na substância cinzenta. A doença foi reproduzida experimentalmente em dois ovinos que apresentaram ascite, desvios vasculares (shunts) porto-sistêmicos e sinais nervosos com lesões histológicas semelhantes a dos casos espontâneos. Na técnica de imuno-histoquímica houve marcação fraca ou ausente do citoplasma astrocitário para o anticorpo anti-GFAP em seis ovinos evidenciando uma alteração degenerativa, em que os astrócitos acumulam corpos densos e reduzem o volume de GFAP. Houve marcação positiva para o anticorpo anti-S100 em oito ovinos, incluindo os dois ovinos experimentais o que sugere reatividade celular, com proliferação mitocondrial e de retículo endoplasmático liso. Estas alterações são caraterísticas dos efeitos da amônia nos astrócitos. Conclui-se que na intoxicação por T. cinerea em alguns ovinos ocorrem sinais nervosos em consequência da encefalopatia hepática.(AU)


In the semiarid region of northeastern Brazil, Tephrosia cinerea causes periacinar hepatic fibrosis in sheep with severe ascites and, occasionally, nervous signs. Sixteen sheep from six outbreaks of T. cinerea poisoning were studied. All sheep had histologic lesion of periacinar fibrosis and six showed, in the brain, vacuolization (spongy degeneration) of the white matter and junction between grey and white matter and presence of Alzheimer type II astrocytes in the grey matter. The disease was produced experimentally in two sheep, that presented porto-sistemic shunts and similar histologic lesions as those observed in the spontaneous cases. Immunohistochemistry revealed weak labelling with anti-GFAP antibodies suggesting a degenerative alteration of astrocytes with accumulation of dense bodies and reduction of the GFAP. There was strong labelling with anti-S100 antibodies suggesting cellular reactivity with proliferation of mitochondria and endoplasmatic reticulum. Such alterations are characteristic of the effects caused by ammonia on the astrocytes. It is concluded that in poisoning by T. cinerea nervous signs due to hepatic encephalopathy occur in some sheep.(AU)


Assuntos
Animais , Ovinos/fisiologia , Encefalopatia Hepática/veterinária , Tephrosia/toxicidade
8.
Pesqui. vet. bras ; 38(4): 635-641, abr. 2018. tab, graf, ilus
Artigo em Português | VETINDEX | ID: vti-19475

RESUMO

A intoxicação por Tephrosia cinerea causa fibrose hepática periacinar em ovinos na região semiárida do Nordeste, com quadro clínico de ascite acentuada, e, ocasionalmente, com sinais neurológicos. Neste trabalho foram estudadas 16 ovinos em 6 surtos de intoxicação por T. cinerea. Todos os ovinos apresentaram lesões histológicas de fibrose periacinar e seis apresentaram, no encéfalo, vacuolização da substância branca e da junção entre a substância branca e a cinzenta com presença de astrócitos de Alzheimer tipo II na substância cinzenta. A doença foi reproduzida experimentalmente em dois ovinos que apresentaram ascite, desvios vasculares (shunts) porto-sistêmicos e sinais nervosos com lesões histológicas semelhantes a dos casos espontâneos. Na técnica de imuno-histoquímica houve marcação fraca ou ausente do citoplasma astrocitário para o anticorpo anti-GFAP em seis ovinos evidenciando uma alteração degenerativa, em que os astrócitos acumulam corpos densos e reduzem o volume de GFAP. Houve marcação positiva para o anticorpo anti-S100 em oito ovinos, incluindo os dois ovinos experimentais o que sugere reatividade celular, com proliferação mitocondrial e de retículo endoplasmático liso. Estas alterações são caraterísticas dos efeitos da amônia nos astrócitos. Conclui-se que na intoxicação por T. cinerea em alguns ovinos ocorrem sinais nervosos em consequência da encefalopatia hepática.(AU)


In the semiarid region of northeastern Brazil, Tephrosia cinerea causes periacinar hepatic fibrosis in sheep with severe ascites and, occasionally, nervous signs. Sixteen sheep from six outbreaks of T. cinerea poisoning were studied. All sheep had histologic lesion of periacinar fibrosis and six showed, in the brain, vacuolization (spongy degeneration) of the white matter and junction between grey and white matter and presence of Alzheimer type II astrocytes in the grey matter. The disease was produced experimentally in two sheep, that presented porto-sistemic shunts and similar histologic lesions as those observed in the spontaneous cases. Immunohistochemistry revealed weak labelling with anti-GFAP antibodies suggesting a degenerative alteration of astrocytes with accumulation of dense bodies and reduction of the GFAP. There was strong labelling with anti-S100 antibodies suggesting cellular reactivity with proliferation of mitochondria and endoplasmatic reticulum. Such alterations are characteristic of the effects caused by ammonia on the astrocytes. It is concluded that in poisoning by T. cinerea nervous signs due to hepatic encephalopathy occur in some sheep.(AU)


Assuntos
Animais , Ovinos/fisiologia , Encefalopatia Hepática/veterinária , Tephrosia/toxicidade
9.
Braz. arch. biol. technol ; 61: e18180028, 2018. graf
Artigo em Inglês | LILACS | ID: biblio-974111

RESUMO

ABSTRACT Extracts of the seeds of Tephrosia vogelii Hook. f. were studied in relation to its chemical composition and toxicity to the brown stink bug Euschistus heros (F.). The extracts were obtained in ethyl acetate and ethanol in the sequence according to the polar nature of the solvents. Extracts were sprayed in concentration of 1.0, 2.5, 5.0, 7.5 and 10% on third-instars nymphs and adults, and mortality was recorded. Presence two rotenoids in ethyl acetate was detected, with analyzed with gas chromatography-mass spectrometry (GC-MS). Crude fraction analyses confirmed the presence of these rotenoids (tephrosin - 2.71% in ethyl acetate and 3.66% in methanol; and deguelin - 10.46% in ethyl acetate and 1.22% in methanol) and three other rotenoids in small amounts. Eight days after applications, ethyl acetate caused more stink bugs mortality and on less time than ethanol extract, because great quantity of rotenoids, as polarity. Concentrations above to 1 and 2.5% of the ethyl acetate extracts caused mortality above 80% of the nymphs and adults of E. heros, respectively. Concentration were considered high, thus chemist analyzes demonstrated high rotenoids presence. In conclusion, seed T. vogelli extracts, rich in deguelin and tephrosin (3:1), cause mortality of E. heros, however, high concentration are necessary.


Assuntos
Glycine max , Cimicidae , Tephrosia/química , Glicina
10.
Rev. biol. trop ; 64(3): 1129-1141, jul.-sep. 2016. tab, ilus
Artigo em Inglês | LILACS | ID: biblio-958201

RESUMO

AbstractLocal communities in some Asian, African and American countries, use plant toxins in fish poisoning for fishing activities; however, the effects of this practice on the particular wild fish assemblages is unknown. This study was conducted with the aim to investigate the effects of fish poisoning using Tephrosia candida, on freshwater fish diversity and abundance in streams at the boundary of the World Natural Heritage site, Sinharaja Forest Reserve, Sri Lanka. A total of seven field trips were undertaken on a bimonthly basis, from May 2013 to June 2014. We surveyed five streams with similar environmental and climatological conditions at the boundary of Sinharaja forest. We selected three streams with active fish poisoning practices as treatments, and two streams with no fish poisoning as controls. Physico-chemical parameters and flow rate of water in selected streams were also measured at bimonthly intervals. Fish were sampled by electrofishing and nets in three randomly selected confined locations (6 x 2 m stretch) along every stream. Fish species were identified, their abundances were recorded, and Shannon-Weiner diversity index was calculated for each stream. Streams were clustered based on the Bray-Curtis similarity matrix for fish composition and abundance. Physico-chemical parameters of water were not significantly different among streams (P > 0.05). A total of 15 fish species belonging to four different orders Cypriniformes, Cyprinodontiformes, Perciformes and Siluriformes were collected; nine species (60 %) were endemic, and six (40 %) were native species. From these, 13 fish species were recorded in streams with no poisoning, while five species were recorded in streams where poisoning was practiced. Four endemic and one native fish species were locally extinct in streams where fish poisoning was active. Fish abundance was significantly higher in control streams (32-39/m2) when compared to treatment streams (5-9/m2) (P < 0.05). We concluded that fish poisoning with T. candida may have resulted in a significant reduction in species richness, total abundance and Shannon-Weiner diversity index of fish species in the studied streams at the boundary of Sinharaja forest. We recommend that this fishing practice should be strictly regulated, and to inform local communities about the legal status of fish poisoning, its consequences and the importance of fish diversity for local livelihoods and conservation purposes. Rev. Biol. Trop. 64 (3): 1129-1141. Epub 2016 September 01.


ResumenLas comunidades de algunos países asiáticos, africanos y americanos utilizan las toxinas de las plantas para pescar, sin embargo, los efectos de esta práctica en grupos de peces silvestres son desconocidos. Este estudio se llevó acabo con el objetivo de investigar los efectos del envenenamiento de peces con Tephrosia candida en la diversidad y abundancia de peces de agua dulce en riachuelos de la frontera la Reserva Sinharaja en Sri Lanka. En total se realizaron siete giras bimensuales al campo de mayo 2013 a junio 2014. Se muestrearon cinco riachuelos con condiciones ambientales y climáticas similares en la frontera de la reserva de Sinharaja. Como tratamientos se seleccionaron tres riachuelos con práctica activa de envenenamiento de peces y dos riachuelos sin envenenamiento de peces como controles. También, en intervalos bimensuales, se midieron los parámetros físico-químicos y de corriente del agua en riachuelos seleccionados. Se utilizó la electropesca y redes en tres sitios (6 x 2 m) seleccionados al azar a lo largo de cada riachuelo para el muestreo de peces. Se identificaron los peces a nivel de especie, se anotó su abundancia y se calculó el índice de diversidad de Shannon-Weiner para cada riachuelo. Con base en la matriz de similitud de Bray-Curtis se agruparon los riachuelos para composición y abundancia de peces. Los parámetros físicoquímicos del agua fueron no significativamente distintos entre los riachuelos (P > 0.05). Se recolectó un total de 15 especies de peces que pertenecen a cuatro órdenes: Cypriniformes, Cyprinodontiformes, Perciformes y Siluriformes; nueve especies (60 %) fueron endémicas y seis (40 %) nativas. Trece especies se encontraron en riachuelos donde no se practica el envenenamiento mientras que cinco especies se encontraron en riachuelos donde sí se daba esta práctica. Cuatro especies endémicas y una nativa estaban extintas en riachuelos donde la práctica del envenenamiento era activa. La abundancia de peces fue significativamente alta en los riachuelos control (32-39/m2) al compararse con los tratamientos (5-9/m2) (P < 0.05). Se concluye que el envenenamiento de peces con T. candida puede haber resultado en una reducción significativa de la riqueza de especies, la abundancia total y el índice de diversidad de Shannon-Weiner de las especies de peces en los riachuelos estudiados en la frontera de la reserva Sinharaja. Se recomienda que esta práctica de pesca sea estrictamente regulada y que se informe a las comunidades locales acerca del estado legal del envenenamiento de peces, sus consecuencias y de la importancia de la diversidad de peces para el sustento local y para propósitos de conservación.


Assuntos
Animais , Tephrosia/intoxicação , Rios/química , Peixes , Especificidade da Espécie , Sri Lanka , Florestas , Análise de Variância , Densidade Demográfica , Estatísticas não Paramétricas , Biodiversidade
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA