Duration of an induced resistance of sheep to acute poisoning by Crotalaria retusa seeds / Duração da resistência induzida por Crotalaria retusa em ovinos

The aim of this study was to determine the duration of the resistance after the end of the ingestion of non-toxic doses of Crotalaria retusa seeds. Ten sheep were divided into 3 groups of 3 animals each and a control group with 1 sheep. To induce resistance, sheep in groups 1, 2 and 3 received 20 daily doses of 2g kg-1 of C. retusa seeds, followed by 7 daily doses of 4g kg-1. To determine the duration of resistance the sheep in groups 1, 2 and 3 were challenged orally, 3, 7 and 15 days, respectively, after receiving the last dose of 4g kg-1, with a single dose of 5g kg-1. Sheep of groups 1 and 2 did not develop overt signs of poisoning. Two sheep of group 3, challenged 15 days after the end of the resistance induction period, showed signs of acute poisoning and died. These results suggest that the induced resistance of sheep to acute poisoning by C. retusa seeds is of short duration, from 7 to 15 days.

O objetivo deste estudo foi determinar a duração da resistência após a ingestão de doses não tóxicas de sementes de Crotalaria retusa. Dez ovinos foram divididos em três grupos com três animais cada e um grupo controle com um ovino. Para induzir resistência, ovinos dos grupos 1, 2 e 3 receberam 20 doses diárias de 2g kg-1 de sementes de Crotalaria retusa, seguidos de sete doses de 4g kg-1 durante 7 dias. Para determinar a duração da resistência, ovinos dos grupos 1, 2 e 3 foram desafiados oralmente, 3, 7 e 15 dias, respectivamente, após receberem a última dose de 4g kg-1, com uma dose única de 5g kg-1. Ovinos dos grupos 1 e 2 não desenvolveram sinais de intoxicação. Dois ovinos do grupo 3, desafiados 15 dias após o período de indução de resistência, apresentaram sinais de intoxicação aguda e morreram. Estes resultados sugerem que a resistência induzida de ovinos à intoxicação aguda por sementes de C. retusa é de curta duração, de 7 a 15 dias.

Duration of an induced resistance of sheep to acute poisoning by Crotalaria retusa seeds / Duração da resistência induzida por Crotalaria retusa em ovinos

The aim of this study was to determine the duration of the resistance after the end of the ingestion of non-toxic doses of Crotalaria retusa seeds. Ten sheep were divided into 3 groups of 3 animals each and a control group with 1 sheep. To induce resistance, sheep in groups 1, 2 and 3 received 20 daily doses of 2g kg-1 of C. retusa seeds, followed by 7 daily doses of 4g kg-1. To determine the duration of resistance the sheep in groups 1, 2 and 3 were challenged orally, 3, 7 and 15 days, respectively, after receiving the last dose of 4g kg-1, with a single dose of 5g kg-1. Sheep of groups 1 and 2 did not develop overt signs of poisoning. Two sheep of group 3, challenged 15 days after the end of the resistance induction period, showed signs of acute poisoning and died. These results suggest that the induced resistance of sheep to acute poisoning by C. retusa seeds is of short duration, from 7 to 15 days.(AU)

O objetivo deste estudo foi determinar a duração da resistência após a ingestão de doses não tóxicas de sementes de Crotalaria retusa. Dez ovinos foram divididos em três grupos com três animais cada e um grupo controle com um ovino. Para induzir resistência, ovinos dos grupos 1, 2 e 3 receberam 20 doses diárias de 2g kg-1 de sementes de Crotalaria retusa, seguidos de sete doses de 4g kg-1 durante 7 dias. Para determinar a duração da resistência, ovinos dos grupos 1, 2 e 3 foram desafiados oralmente, 3, 7 e 15 dias, respectivamente, após receberem a última dose de 4g kg-1, com uma dose única de 5g kg-1. Ovinos dos grupos 1 e 2 não desenvolveram sinais de intoxicação. Dois ovinos do grupo 3, desafiados 15 dias após o período de indução de resistência, apresentaram sinais de intoxicação aguda e morreram. Estes resultados sugerem que a resistência induzida de ovinos à intoxicação aguda por sementes de C. retusa é de curta duração, de 7 a 15 dias.(AU)

Pulmonary and hepatic lesions caused by the dehydropyrrolizidine alkaloid-producing plants Crotalaria juncea and Crotalaria retusa in donkeys.

The effects and susceptibility of donkeys to Crotalaria juncea and Crotalaria retusa poisoning were determined at high and low doses. Seeds of C. juncea containing 0.074% of dehydropyrrolizidine alkaloids (DHPAs) (isohemijunceines 0.05%, trichodesmine 0.016%, and junceine 0.008%) were administered to three donkeys at 0.3, 0.6 and 1 g/kg body weight (g/kg) daily for 365 days. No clinical signs were observed and, on liver and lung biopsies, the only lesion was a mild liver megalocytosis in the donkeys ingesting 0.6 and 1 g/kg/day. Two other donkeys that received daily doses of 3 and 5 g seed/kg showed initial respiratory signs 70 and 40 days after the start of the administration, respectively. The donkeys were euthanized following severe respiratory signs and the main lung lesions were proliferation of Clara cells and interstitial fibrosis. Three donkeys ingested seeds of C. retusa containing 5.99% of monocrotaline at daily doses of 0.025, 0.05 and 0.1 g/kg for 365 days. No clinical signs were observed and, on liver and lung biopsies, the only lesion was moderate liver megalocytosis in each of the three donkeys. One donkey that received a single dose of 5 g/kg of C. retusa seeds and another that received 1 g/kg daily for 7 days both showed severe clinical signs and died with diffuse centrilobular liver necrosis. No lung lesions were observed. Another donkey that received a single dose of 2.5 g/kg of C. retusa seeds showed no clinical signs. The hepatic and pneumotoxic effects observed are consistent with an etiology involving DHPAs. Furthermore, the occurrence of lung or liver lesions correlates with the type of DHPAs contained in the seeds. Similarly as has been reported for horses, the data herein suggest that in donkeys some DHPAs are metabolized in the liver causing liver disease, whereas others are metabolized in the lung by Clara cells causing lung disease.

Evaluation of the leishmanicide action of ethanol extracts of Crotalaria retusa L (Fabaceae) / Avaliação da ação leishmanicida do extrato etanólico da Crotalaria retusa L (Fabaceae)

The purpose of the present work is to conduct an evaluation of the cytotoxicity of ethanol extracts and the total alkaloid fraction (TAF) from Crotalaria retusa for procyclic promastigotes cells of Leishmania chagasi. The kinetic study of extraction assisted by ultrasound of the total alkaloids present in Crotalaria retusa made it possible the optimization of the extraction parameters. It was evaluated the leishmanicide action of the TAF which did not show toxic activity for cells of the parasite in high concentrations. It was observed a powerful leishmanicide action of the ethanol extracts (10 and 30 percent) after the concentration of 5.6 mg/mL of Crotalaria retusa, and the ethanol present in the extractive solution (10 and 30 percent) in the concentration from 70 and 210 x 10-4 percent, respectively. These results suggest that the cytotoxicity of the ethanol extract of Crotalaria retusa at 10 and 30 percent for cells of Leishmania chagasi, can be associated only to the concentration of the alcohol present in the extract.

O presente trabalho se propõe avaliar a atividade citotóxica do extrato etanólico bruto e da fração dos alcalóides totais (FAT) da planta Crotalaria retusa para células promastigotas metacíclicas de Leishmania chagasi. O estudo da cinética de extração por ultra-som para os alcalóides totais da Crotalaria retusa, tornou possível a otimização dos parâmetros de extração. Foi avaliada a ação leishmanicida da FAT da planta em estudo, a qual não mostrou atividade citotóxica em altas concentrações. Foi observado uma potente ação leishmanicida para os extratos etanólicos (10 e 30 por cento) após a concentração de 5,6 mg/mL de Crotalaria retusa e do etanol presente na solução extrativa (10 e 30 por cento) nas concentrações de 70 e 210 x 10-4 por cento, respectivamente. Estes resultados sugerem a citotoxicidade do extrato etanólico da Crotalaria retusa de 10 a 30 por cento para células de Leishmania chagasi, associada possivelmente à concentração do etanol presente no extrato.