ABSTRACT
Cassava is an important African food crop, where it is a staple to about 250 Million people. It is a household name in Nigeria, the world largest producer of the root crop. It is propagated from stem cuttings and well known for its adaptation to wide range of adaphoclimatic conditions and including those unfavourable for other crops. However cassava production, exploitation, utilization and acceptance are limited by diseases and pests, cyanogenesis, low protein content and quality, and post-harvest physiological deterioration. The breeding research activities of IITA (International Institute of Tropical Agriculture) Ibadan, Nigeria, CIAT (International Centre of Tropical Agriculture) located in Cali, Colombia and National Root Crop Research Institute (NRCRI), Umudike, Nigeria have transformed cassava to double as a food security crop as well as a cash and industrial crop. Of recent, Bio Cassava Plus, an initiative sponsored by Bill and Melinda Gates, has been using experimental biotechnology approaches to address several of the main constraints to African cassava. This review presents the many advantages of cassava to the small-scale farmer and its potentials for industrial applications. It also describes the roles of biotic and abiotic factors hampering the production yield, root quality, nutritional adequacy, marketability and acceptance, and commercial processes. The use of conventional breeding and biotechnology in unravelling the milieu of these constraints is discussed as well.
ABSTRACT
Passiflora foetida is mentioned as a toxic plant by farmers in northeastern Brazil. This research aimed to establish the toxicity of P. foetida for goats, in different seasons of the year, and to determine its toxic compound. Initially, the plant collected two days before administration was non toxic at the daily dose of 40g per kg of body weight (g/kg) given during two days. Furthermore, the plant was administered immediately after collection at a dose of 4-8g/kg to four goats. The animal that ingested 8g/kg showed severe clinical signs, but recovered after treatment with sodium thiosulfate. The other three goats showed mild signs of poisoning and recovered spontaneously. The plant was then administered during different seasons to 23 goats at the dose of 10g/kg. The plant was significantly (P<0.05) more toxic during the dry season than during the rainy season; 11 out of 14 goats that received the plant in the dry season showed clinical signs, but only 3 out of 13 goats that ingested the plant during the rainy season had signs. All goats with clinical signs recovered after the administration of sodium thiosulfate. Clinical signs were apathy, tachycardia and tachypnea, jugular venous pulse, incoordination, bellowing, mydriasis, and sternal recumbence followed by lateral recumbence. Before each administration the plant was tested for cyanide by the picric acid paper test to estimate the cyanide concentration in the plant, which was defined as slight, moderate, high, and very high. Samples with slight reaction were not toxic, those with moderate reaction induced mild signs of poisoning, and those with high reaction induced severe clinical signs. Samples with very high concentrations of cyanide were not observed. The results demonstrated that P. foetida is a cyanogenic plant, which causes poisoning after the ingestion of fresh leaves, mainly during the dry period.
Passiflora foetida é mencionada por produtores da região Nordeste como causa de intoxicação espontânea em animais. Este trabalho teve por objetivos avaliar a toxicidade de P. foetida em caprinos e determinar seu princípio ativo e a época do ano em que a mesma é tóxica. Inicialmente a planta administrada em duas doses diárias de 40g por kg de peso animal (g/kg) coletada dois dias antes da administração não resultou tóxica. Posteriormente a planta administrada imediatamente após a coleta resultou tóxica nas doses que variaram de 4 a 8 g/kg, em quatro caprinos. O animal que recebeu 8g/kg apresentou sinais clínicos graves e recuperou-se após a administração de tiossulfato de sódio. Os demais caprinos apresentaram sinais menos graves e se recuperaram espontaneamente. Posteriormente, a planta foi administrada em diferentes épocas a 23 caprinos na dose de 10g/kg. A planta foi significativamente mais tóxica (P<0,05) na época seca; no total, dos 14 caprinos que receberam a planta na época seca, 11 apresentaram sinais clínicos de intoxicação e dos 13 caprinos que receberam a planta na época das chuvas, apenas 3 apresentaram sinais clínicos. Todos os animais que apresentaram sinais clínicos, se recuperaram após a administração de tiosulfato de sódio. Os sinais clínicos caracterizavam-se por apatia, pulso venoso positi-vo, ataxia, berros, taquicardia e taquipneia, midríase e decúbito esternal seguido por decúbito lateral. Antes de cada administração era feito o teste do papel picrosódico para estimar o teor de cianeto na planta, classificando a reação em discreta, leve, moderada e acentuada. As amostras com reação discreta não apresentaram toxicidade, as com reação leve induziram sinais leves e as com reação moderada causaram sinais graves ou moderados de intoxicação. Não foram observados testes com reação acentuada. Os resultados do trabalho demonstram que P. foetida é uma planta cianogênica que causa intoxicação após a ingestão das folhas frescas[...]
Subject(s)
Animals , Plants, Toxic/poisoning , Plants, Toxic/toxicity , RuminantsABSTRACT
Cnidoscolus phyllacanthus (Euphorbiaceae), com nome popular de favela, é uma planta normalmente espinhosa comum na caatinga. É considerada como forrageira e os animais, principalmente durante a seca, consomem as folhas que estão ao seu alcance ou as folhas secas caídas. A intoxicação espontânea por esta planta é relatada por fazendeiros no semi-árido quando animais têm acesso a plantas ou ramos recentemente cortados. Diferentes partes da planta moídas e secas, diluídas em água, são utilizadas por caçadores para matar pássaros. Para determinar a toxicidade de C. phyllacanthus, folhas verdes de plantas sem espinhos foram administradas a uma cabra em pequenas quantidades por via oral. Após o consumo de 4,7g por kg de peso do animal (g/kg) a cabra apresentou taquicardia, taquipneia, dispnéia, nistagmo, opistótono e decúbito esterno abdominal seguido de decúbito lateral. A morte ocorreu 30 minutos após o começo dos sinais. Folhas frescas de plantas sem espinho foram administradas a 8 caprinos em doses de 0,5-2,5g/kg sem que causassem sinais clínicos. Três animais apresentaram sinais clínicos após a ingestão de 3g/kg. Os sinais clínicos foram similares aos observados na intoxicação por ácido cianídrico e dois animais tratados com uma solução de tiossulfato de sódio a 20 por cento, na dose de 0,5ml/kg se recuperaram rapidamente em seguida ao tratamento. O terceiro recuperou-se espontaneamente. Folhas das mesmas plantas foram secadas ao sol durante períodos varáveis de 8-30 dias. O caprino que ingeriu a planta que tinha sido secada por 8 dias morreu após a ingestão de 3g/kg. O caprino que ingeriu a planta secada por 9 dias apresentou sinais clínicos após a ingestão de 1,13g/kg e se recuperou. Os caprinos que ingeriram a planta exposta ao sol por 10-29 dias apresentaram sinais clínicos após a ingestão de 3g/kg e se recuperaram espontaneamente ou mediante tratamento com tiossulfato de sódio. O caprino que ingeriu a planta que tinha sido exposta...
Cnidoscolus phyllacanthus (Euphorbiaceae), with the common name favela, is a generally spiny plant of the Brazilian semiarid. Mainly during the dry season livestock browse its leaves from the shrubs or ingest the dry leaves fallen to the ground. Farmers report the spontaneous poisoning by this plant when livestock has access to shrubs or branches that had been cut. Different parts of the ground fresh plant, diluted in water, are used by people in the semiarid to hunt birds. To determine the toxicity of C. phyllacanthus, leaves of the non-spiny plant were fed by hand to a goat by putting small amount into its mouth. After the consumption of 4.7g/kg body weight, the goat had tachycardia, tachypnoea, dyspnoea, nystagmus, opisthotonos and sternal recumbence. The death occurred 30 minutes after the onset of clinical signs. Fresh leaves from the same plants were given to 8 goats at doses of 0.5-2.5g/kg without causing clinical signs. Three goats showed clinical signs after the ingestion of 3g/kg. Clinical signs were similar to those observed in cyanide poisoning. Two goats given 0.5mg/kg of a 20 percent solution of sodium thiosulphate recovered immediately after treatment. Another goat recovered spontaneously. Leaves from the same plants were sun-dried during variable periods for 8-30 days, and then given to 8 goats. The goat that ingested the plant dried at the sun during 8 days died after the ingestion of 3 g/kg. The goat that ingested the plant, exposed to the sun for 9 days, showed clinical signs after the ingestion of 1.13g/kg, but recovered spontaneously. The goats that ingested the leaves exposed to the sun during 10-29 days showed clinical signs after the ingestion of 3g/kg, but recovered spontaneously or after treatment with sodium thiosulphate. No clinical signs were observed in the goat that ingested the plant that had been exposed to the sun during 30 days. In another experiment ground leaves of the plant were dried at the sun for...
Subject(s)
Animals , Euphorbiaceae/adverse effects , Euphorbiaceae/toxicity , Goats , Mortality , Thiosulfates/administration & dosageABSTRACT
Observations on the developement of pathological changes of rat brain, together with dynamic detection of CN- concentrations in blood and brain tissue and quantitive analysis of brain cytochrome oxidase activity, are carried out within 24 h after acute cyanide intoxication (4.5mg/kg i.p.) . The results indicate that in the cyanide poisoning with the dose under lethality (80%LD) , the pathological changes in rat brain appear, especially in cytochrome oxidase poorly- contained areas, including! 1 ) degeneration and necrosis of neurons and gliocytes; 2) degeneration, swelling and lysis of different cell projection components; 3) the myelinoclasis of myelinated nerve fibers. Those changes undergo a dynamic course divided into three phases: 1 ) the phase of metabolic disturbance; 2) of response to injury; and 3) of restoration. The authors consider that the acute poisoning displayed by the animal after NACN injection is directly caused by the intense inhibation of brain cytochrome oxidase; the secondary lesions of brain structure may be responsible for the manifestations such as trembling, unstable, and ataxia etc.occur later. The mechanisms of the brain pathological changes after cyanide intoxication are also disscussed.
ABSTRACT
The toxicity of HCN inhaled via the respiratory tract in dogs and the therapeutic effects of DMAP and AmNO2 for such form of HCN intoxication were studied. The LD50 of HCN when inhaled was 850.4?80.4?g/kg.When the dosage of 2?LD50 of HCN was given to the experimental animals, the signs of intoxication developed rapidly. Uneasiness, struggling, strident barking, and respiratory excitation were observed several seconds after the exposure. Subsequently there was spasm of the extensors and rigidity of the extremities. Finally general inhibition and paralysis ensued. Respiration and heart beat stopped 6 and 7 minutes after exposure. If DMAP (3.25 mg/kg intramuscularly) or AmNO2 (2 ampules through inhalation) was administered 15 seconds after exposure, the survival rate of the animals was 90% or 100% respectively.When the dosage of 4?LD50 of HCN was inhaled and the two drugs were administered 45 seconds after exposure, the survival rate of the animals treated with DMAP remained as high as 90% (9/10) .But the survival rate of those treated with two ampules of AmNO2 or even three ampules reduced to 20% or 40% respectively.The amount of HCN inhaled during respiratory intoxication, the problems of early diagnosis and the administration of DMAP at the site of accident were analyzed and discussed.
ABSTRACT
The toxicity of HCN was determined first.The experimental animals were intoxicated with a HCN concentration of 1103.8?48.32 Y/L and were exposed for 4.55?2.04 minutes.The mortality rate in 24 hrs was recorded.The LDEO,sLD50,and LD99 were calculated as 844.31?/kg,172.39?/kg and 959.18?/kg respectively.Two preparations of DMAP injection were found to have preserved rather good anti-HCN potency even though they had been kept under room temperature for about one year.All the 11 dogs survigd a dose of 4 LD50 of HCN in halation poisoning when DMAP was injected intramuscularly 1 minute after exposure.Another 5 dogs inflicted with similar HCN intoxication were also all saved when intravenous DMAP injection was given at the time of respiratory arrest. The cyanide level in the blood of the dogs after inhalation of HCN was determined by spectrophotofluorometry with pyridoxal.The blood concentration after inhalation of a lethal dose of HCN was 110?26.6?/100 ml at the moment of respiratory arrest.DMAP after intramuscular injection can shift the cyanide combined with cytochrome oxidase to red blood cells to form ferrihemoglobin cyanide,and cell respiration is then restoredEventually the dogs could survive the 4 LD50 HCN intoxication.
ABSTRACT
This paper reports the antagonistic effect of sodium cobaltinitrite by intramus-cular injection on cyanide intoxication. The sodium cobaltinitrite (10%) dime-thylsulfoxide solution was administrated intramuscularly when convulsion appeared in dogs 5-10 min after intramuscular injection of potassium cyanide(1-2.5LD) or 15s after inhalation of hydrocyanic acid (2LD50). The animal survival rate was 20/22 and 8/10, respectively. The cats intoxicated by lethal dose of hydrocyanic acidinhalation were given sodium cobaltinitrite intramuscularly, and a good therapeutic effect was also obtained.This study provides an experiment basis in search of an antagonist of cyanide, which takes effect rapidly, is administrated conveniently and is suitable rescue in the field, with a convenient administrating means.