• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 210
  • 154
  • 20
  • 17
  • 15
  • 11
  • 10
  • 9
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 3
  • Tagged with
  • 481
  • 238
  • 146
  • 86
  • 68
  • 60
  • 54
  • 49
  • 38
  • 36
  • 35
  • 34
  • 32
  • 32
  • 31
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
231

In vitro cytotoxic effects of selected Nigerian medicinal plant extracts on cancer cell lines

Baatjies, Lucinda January 2012 (has links)
Cancer is a disease that imposes a heavy burden on public health and poses a challenge to science. The World Health Organization estimates that 80 percent of people in developing countries of the world rely on traditional medicine for their primary health needs, and about 85 percent of traditional medicine involves the use of plant extracts. This is particularly true in Africa where a large percentage of the population depends upon medicinal plants for health care. Therefore, detailed screening and evaluation of bioactive substances for chemotherapeutic purposes of African plants are urgently warranted. Furthermore, this will serve to validate the efficacy and safety of African traditional medicine. The current study investigated the in vitro cytotoxic effects of 17 ethanolic extracts of the following 16 plants used in traditional anticancer medicine in Nigeria: Sapium ellipticum leaves, Sapium ellipticum stembark, Combretum paniculatum, Celosia trigyna, Pupalia lappacea, Justica extensa, Hedranthera barteri leaves, Alternanthera sessilis, Ethulia conyzoides leaves, Lannea nigritana stembark, Combretum zenkeri root, Combretum molle leaves, Adenanthera parvoniana, Lannea acida, Cyathula achyranthoides, Drymaria cordata, Cyathula prostrata, against HeLa cancer cells. Five of the most promising extracts (Sapium ellipticum leaves, Combretum paniculatum, Celosia trigyna, Drymaria cordata, Cyathula prostrata) were selected for further screening against HT29 and MCF-7 cancer cells. Of the five, the first two were investigated further based on their activities in the screening phase. The S. ellipticum leaf extract yielded IC50 values of 88.60 ± 0.03 and 93.03 ± 0.03 μg/ml against HeLa and MCF-7, respectively. The toxicity was also evaluated on normal cells and an IC50 of 77.66 μg/ml was obtained for peripheral blood mononuclear cells (PBMCs). The IC50 values for proliferating and confluent Chang liver cells were both >125 μg/ml. These results suggest that the extract may be selective for specific cell types. Bio-assay guided fractionation of the S. ellipticum ethanolic extract yielded two active fractions; chloroform and ethyl acetate. Two compounds isolated from the chloroform extract were screened against the three cancer cell lines and found to be inactive. Three compounds were isolated from the ethyl acetate fraction and revealed IC50 values < 62.5 and < 31 μg/ml against MCF-7. Unfortunately these two compounds soon lost activity before any further work could be done on them and work was continued with the crude extract.
232

Evaluation of plant extracts : artemisia afra and annona muricata for inhibitory activities against mycobacterium tuberculosis and human immunodeficiency virus

Pruissen, Megan Colleen January 2013 (has links)
Mycobacterium tuberculosis and Human Immuno-Deficiency Virus (HIV) have a high prevalence in South Africa. The development and spread of drug resistant tuberculosis is a serious problem which is exacerbated by tuberculosis (TB) co-infection in HIV patients. Traditional medicinal plants like Annona muricata and Artemisia afra are used for respiratory ailments and antiviral therapies respectively. The aim of this study was to evaluate Annona muricata (ethanolic extract) and Artemisia afra (ethanolic and aqueous extracts) for inhibitory activities against M. tuberculosis and HIV. In vitro bioassays for anti-TB activity included: microplate alamar blue assay (MABA), flow cytometry and ρ-iodonitrotetrazolium chloride assays while anti-HIV activity was determined using an HIV-1 reverse transcriptase colorimetric ELISA kit and an HIV-1 integrase colorimetric immunoassay. Cytotoxicity of plant extracts were assessed by the MTT assay on Chang Liver and HepG2 cells. Potential synergistic effects were determined using the basis of Combination Index. Potential interactions of plant extracts with drug metabolic pathways were evaluated with the Glutathione-S-Transferase assay kit as well as the CYP3A4 assay kit. A. muricata ethanolic extract exhibited anti-TB activity with MIC 125 μg/mL. MABA was shown to be the most sensitive and effective method for the detection of anti-TB activity. Artemisia afra aqueous extract showed HIV-1 reverse transcriptase inhibition exhibiting ˃85 percent inhibition at 1 mg/mL while the ethanolic extracts of A. afra and A. muricata showed inhibition of HIV-1 integrase activity at ˃86.8 percent and ˃88.54 percent respectively at concentrations >0.5 - 4 mg/mL. The aqueous extract of A. afra displayed inhibition of HIV-1 integrase ˃52.16 percent at 0.5 mg/mL increasing to 72.89 percent at 4 mg/ml of the extract. A. muricata was cytotoxic at an IC50 of 30 μg/mL and 77 μg/mL on Chang Liver and HepG2 cells respectively, whilst A. afra aqueous and ethanol extracts were not cytotoxic to both cell lines. The ethanolic extract of A. muricata showed both antagonistic and synergistic properties at various IC values, when used in conjunction with rifampicin. A. afra ethanolic extract interrupted GST activity while aqueous extracts of A. afra and A. muricata had a slight effect. All extracts interrupted CYP3A4 activity, however the ethanolic extracts of A. muricata and A. afra showed greater inhibition than the aqueous extract of A. afra. These extracts should be investigated further as they could be an important source of compounds for treatment of M. tuberculosis and HIV respectively.
233

Assessment of the antibacterial properties of n-Hexane extract of Cocos Nucifera and its interactions with some conventional antibiotics

Akinyele, Taiwo Adesola January 2011 (has links)
Cocos nucifera belong to the family Aracaceae (palm Family). The English name is coconut and it is used extensively as medicinal remedies against infections such as urinary tract infections, gastro intestinal infections, skin and wound infections. The in vitro antibacterial (including anti-listerial and anti-vibrio) properties as well as the evaluation of the combination potentials of the plant extract with six front-line antibiotics were evaluated in this study using standard procedures. The in vitro anti-listerial properties of the crude aqueous and n-Hexane extract of the husk of Cocos nucifera were carried out against 37 Listeria isolates. Twenty-nine of the test organisms were susceptible to the aqueous extract while thirty were susceptible to the n-Hexane extract both at the screening concentration of 25 mg/ml. Minimum Inhibitory Concentration (MIC) values for all the susceptible bacteria ranged between 0.6 - 5.0 mg/ml. For the aqueous extract, average log reduction in viable cell count ranged between 0.32 Log10 and 4.8 Log10 CFU/ml after 8 hours interaction in 1 × MIC and 2 × MIC. For the n-Hexane extract, the log reduction ranged between 2.4 Log10 and 6.2 Log10 CFU/ml after 8 hours interaction in 1 × MIC and 2 × MIC. The time-kill characteristics of the two extracts suggest that at higher concentration (2 × MIC) and longer duration of interaction (8 hr), more bacteria were killed. In vitro anti-vibrio and antibacterial properties experiment revealed that of all the 45 vibrio and 25 bacteria strains that was tested, 37 were susceptible to the aqueous extract and 38 to the n-Hexane extract, while 17 were susceptible to the aqueous extract and 21 to the n-Hexane extract. Minimum Inhibitory Concentration (MIC) values for all the susceptible bacteria ranged between 0.3 - 5.0 mg/ml. viii The time kill studies revealed that for the aqueous extract, average log reduction in viable cell count in time kill assay ranged between 0.12 Log10 and 4.2 Log10 CFU/ml after 8 hr interaction at 1 × MIC and 2 × MIC. For the n-Hexane extract, the log reduction ranged between 0.56 Log10 and 6.4 Log10 CFU/ml after 8 hr interaction in 1 × MIC and 2 × MIC. In the test for the combination interactions, the checkerboard method revealed synergy of 67% and indifferent of 33%, while the time kill assay detected synergy in 72% and indifferent in 28% of the combinations tested. The synergy detected was not specific to any of the antibiotics or the Gram reaction of the bacteria, and no antagonism was detected. We conclude that the aqueous and n-Hexane extract of the husk of C. nucifera contains potential broad spectrum antibiotics resistance modulating compounds that could be relevant in the treatment of infections caused by these pathogens. In addition, the husk which is being discarded as agro waste will opens up a vista of opportunities for utilization for therapeutic purposes
234

Effect of processing on the efficacy and safety of Solanum Aculeastrum Dunal berries

Aboyade, Oluwaseyi Mayode January 2009 (has links)
General Abstract There has been a steady increase in the use of medicinal plants in the last two decades in both developed and developing countries for prevention, management and treatment of diseases. This increase has been due to reasons such as ease of access, better cultural acceptability and compatibility, cost effectiveness and also the bid to “go natural”. Unfortunately, the notion that herbal medicines are relatively safe because they are natural has led to serious and potentially fatal consequences in phytotherapy. The lack of rigorous research to prove the effectiveness and safety of many medicinal plants is of great concern to the health care system. This thesis therefore addresses not just the efficacy, but also the safety of the extracts of the berry of Solanum aculeastrum - a medicinal plant used, among other things, for the treatment of breast cancer in the Eastern Cape Province of South Africa. Particular attention was paid to the possible effect of different processing methods of the berry extracts on inflammation, cytotoxicity, and toxicity. In studying the comparative effects of various processing methods, four different preparations of the extracts were investigated. These include fresh, dried, boiled fresh, and boiled dried berries. While the effect of processing on the anti-inflammatory properties of the extracts was not dose dependent, the percentage reduction in inflammation was highly significant and more prominent in both concentrations of the boiled fresh berries than the reference drug, indomethacin. Furthermore, the four extracts varied in their ability to act either centrally or peripherally in their effect on pain. Assessment of the analgesic response using the formalin test showed that, at both concentrations tested, none of the extracts inhibited the first phase of the formalin test. Furthermore, it was observed that boiling had differing results on the activity of the iii fresh and dried extracts. While boiling of the dried berries reduced pain in the rats, the opposite trend was observed with the boiled fresh berries. Results of the influence of processing of the berries on cytotoxicity indicated that the extracts are potent inhibitors of human breast, cervical and colonic carcinoma cells and the non-cancerous cells (both the actively dividing and confluent Chang liver cells). Although, in terms of relative potency, the fresh berries appeared to be the most active of the extracts, processing of the berries caused an increase in apoptotic cells and a subsequent decrease in the necrotic cells. The effect of processing on the safety of the berry of S. aculeastrum on the rats fed for 28 days was also investigated. The various doses (1, 10 and 25 mg/kg body weight) of all the four extracts did not alter the activity and the weight of the animals throughout the period of treatment. A reduction in organ to body weight ratio of the heart, kidney, liver and spleen was observed in all the extracts. Regarding the haematological parameters, different patterns of effect were observed between the extracts and within the treated doses. The observed alterations in the biochemical parameters by the various extract of Solanum aculeastrum berries at all the doses may have consequential effects on the normal functioning of these organs. In conclusion, this study has shown that there is some justification for the traditional use of the berries of Solanum aculeastrum in the treatment of inflammation related ailments and cancer. However, the medicinal use of the plant also poses considerable health risks. Investigation conducted into the plant’s safety revealed that the berry extracts were nephrotoxic, hepatotoxic, haematotoxic and at higher doses, fatal. Another concern with regard to the plant’s safety is the non-selectivity of its extracts in the inhibition of carcinoma, actively dividing and un-dividing cells. Assessment of the effect of the processing on the berry’s efficacy and safety as herbal iv remedy produced mixed results. On the one hand, processing seemed to improve the extract’s anti-inflammatory and analgesic activity, while reducing its cytotoxic potential. On the other hand, a reduction in the toxicity was observed on the processed extracts compared to the fresh ones. This may be an indication that processing has an overall beneficial effect on the medicinal properties of the plant and should thus be considered as a method of making the berries of Solanum aculeastrum safer for use as a herbal remedy.
235

Epigallocatechin-3-gallate and recombinant human activated protein C and the modulation of acute pancreatitis

Idicula Babu, Benoy January 2012 (has links)
Effective management of acute pancreatitis has for centuries eluded mankind. The disease has a wide spectrum of presentation; the milder form is usually a self limiting condition, whereas the severe form presents as a highly morbid and frequently lethal attack. The ability to predict disease progression on admission would aid in the comprehensive and multidisciplinary management of patients. The perfect predictor of disease progression has been an elusive factor hindering the management of the disease. On systematically reviewing literature and identifying appropriate biochemical markers in predicting progression of acute pancreatitis, the ideal predictor would be a combination of biochemical, clinical and contemporary organ dysfunction scoring systems. Early prediction of disease progression however, is important in the better management of the disease. The pathophysiological changes of acinar cell injury and death are the earliest events that occur in acute pancreatitis. Identification of potential pharmacological interventions offered through valuable insight in to experimental and clinical acute pancreatitis may lead on to the development of various natural and synthetic potential disease modifiers. Green Tea Extracts (GTE) consumed in many parts of the world has been examined as a potential therapeutic medication. Experimental results have demonstrated the effect of GTE on the oxidative pathway significantly ameliorating the effects of pancreatic injury. The various green tea catechins especially Epigallocatechin-3- gallate (EGCG) can perhaps be useful lead compounds for new drug discovery. With no specific targeted therapy for severe acute pancreatitis at present, various medications have been tested. The possibility of targeting initial acinar cell injury may not be a feasible option as patient presentation and management would usually be after this phase. As the disease progresses, severe acute pancreatitis is characterised by inflammation and necrosis. The hypothesis of preserving pancreatic parenchymal microvascular patency and thus ameliorating pancreatic injury through the early administration of recombinant human Activated Protein C (rhAPC) has identified a potential treatment for acute pancreatitis. rhAPC converted from its inactive precursor, protein C, by thrombin acts through fibrinolysis and inhibition of thrombosis. Studies on rhAPC in experimental acute pancreatitis examined the modulation of rhAPC on inflammatory markers, morphology, microvascular thrombosis and apoptosis. The encouraging results from initial experimental work helped set up the Phase 2 clinical trial of administering rhAPC early on in severe acute pancreatitis. Prior to taking this significant step from bench to bed side, the variation in functional protein C levels with the severity of the disease was examined as a precursor to the Phase 2 trial.
236

Insect growth inhibitors from asteraceous plant extracts

Salloum, Gregory Stewart January 1987 (has links)
Petrol and ethanolic extracts of six asteraceous weeds were added to artificial diet and screened for inhibition of larval growth on variegated cutworm, Peridroma saucia (Hbn.). Petrol and ethanolic extracts of Artemisia tridentata and Chamomilla suaveolens and ethanolic extracts of Chrysothamnus nauseosus and Centaurea diffusa were highly inhibitory at five times the naturally occurring concentrations. The two C. suaveolens extracts and the ethanol extract of A. tridentata were active at the natural concentration (100%) and were further examined at 20, 40, 60, and 80% of this level. Inhibition of larval growth was directly related to concentration for each of the three extracts tested. EC₅₀'S (effective concentration to inhibit growth by 50% relative to controls) for the three extracts were 36-42% of the naturally occurring level in the plants. Nutritional indices were calculated for second instar P. saucia feeding on the active ethanolic A. tridentata extract and the petrol extract from C. suaveolens. The relative growth rate (RGR) of P. saucia larvae fed the ethanolic extract of A. tridentata in artificial diet was significantly lower than that in larvae fed diet with the petrol extract of C. suaveolens and larvae on control diet. Dietary utilization was significantly lower for larvae fed the A. tridentata extract. Results of a field trial indicated that a single treatment of A. tridentata extract at the equivalent of 0.2 g/ml could protect cabbage significantly better than the carrier solvent (30% aq ethanol) or distilled water as measured by a visual damage estimate. An insecticide standard, deltamethrin (17.9 µg/1 with 0.4% Superspred TM ), suppressed pest damage significantly better than the A. tridentata-extract treatment. A residual oviposition deterrency to Pieris rapae was found in the field results. Caged experiments in the laboratory confirmed the contact oviposition deterrency of the A. tridentata extract at 0.2 g/ml. Offspring of field-collected P. saucia larvae grew 2.5-fold heavier than larvae from the laboratory colony. However, diet with the A. tridentata extract inhibited both field-collected and laboratory reared saucia larvae equally when compared to their respective controls fed untreated diet. In summary, these results indicate the potential benefit of using specific unrefined plant extracts for growth inhibitors and oviposition deterrents against insect pests. The contribution of individual phytochemicals in the A. tridentata ethanolic extract to growth inhibition or oviposition deterrency is currently speculative. / Land and Food Systems, Faculty of / Graduate
237

Utilização de extratos comerciais derivados de plantas em produtos cárneos : avaliação da atividade antioxidante / Plant-derived commercial extracts on meat products : study on the antioxidant activity

Paglarini, Camila de Souza, 1989- 04 June 2015 (has links)
Orientador: Marise Aparecida Rodrigues Pollonio / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-27T13:09:44Z (GMT). No. of bitstreams: 1 Paglarini_CamiladeSouza_M.pdf: 1935100 bytes, checksum: aef936b63826838b7627e9db7c6d5e14 (MD5) Previous issue date: 2015 / Resumo: Os produtos cárneos são muito susceptíveis à oxidação lipídica, uma das principais reações de deterioração e a causa principal de sabor e odor desagradáveis, redução do valor nutricional e da vida útil, além da formação de compostos tóxicos. O consumo excessivo de produtos cárneos está relacionado com o aumento do risco de algumas doenças, tais como doenças cardiovasculares, câncer, hipertensão e obesidade e assim pesquisas vem sendo desenvolvidas para elaboração de produtos mais saudáveis, dentre os quais destacam-se aqueles com redução de aditivos sintéticos. Neste contexto, o objetivo do presente estudo foi avaliar a atividade antioxidante de extratos comerciais derivados de plantas em matéria-prima cárnea (carne de frango mecanicamente separada - CFMS) e em produto cárneo reestruturado elaborado com diferentes matérias-primas (carne bovina, suína, de frango e CFMS). As concentrações dos extratos naturais foram de 0,125, 0,25, 0,5 e 1,0%, m/m. Os extratos foram caracterizados quanto ao teor de compostos fenólicos, flavonóides totais, atividade antioxidante ORAC, DPPH e ABTS. A oxidação lipídica foi avaliada pela análise de substâncias reativas ao ácido tiobarbitúrico - TBARS. A matéria-prima cárnea foi avaliada crua em ambiente refrigerado (4 °C) nos dias 0, 2, 4, 6, 8 e 10 e o produto cárneo foi avaliado cozido refrigerado (4 °C) nos dias 0, 3 e 6 e cru congelado (-18 °C) nos dias 0, 30 e 60 de vida útil. Quando caracterizados, todos os extratos naturais apresentaram atividade antioxidante, com destaque para os extratos de semente de uva e chá verde. Na CFMS todos os extratos apresentaram potencial antioxidante, sendo que o extrato de romã foi o menos efetivo e assim não foi aplicado no produto cárneo. O extrato de chá verde foi o mais efetivo contra a oxidação nos hambúrgueres cozidos e crus. No entanto os extratos de semente de uva, alecrim e mate também aumentaram a vida útil dos hambúrgueres cozidos. Nos hambúrgueres congelados a vida útil foi aumentada pelos extratos de semente de uva e alecrim. Os extratos naturais apresentaram maior potencial antioxidante nos hambúrgueres quando comparados com o antioxidante sintético BHT. Os resultados obtidos sugerem que extratos comerciais derivados de plantas podem ser utilizados como antioxidantes naturais em produtos cárneos, no entanto, estudos sensoriais tornam-se necessários para viabilizar sua adição. Com relação à oxidação lipídica, é possível a utilização de extratos comerciais derivados de plantas em produtos cárneos, melhorando a sua qualidade nutricional / Abstract: Meat products are very susceptible to lipid oxidation, a major degradation reaction and primary cause of off-flavors, reduction in the nutritional value and shelf life, and formation of toxic compounds. Increased consumption of meat products has been associated with a high risk of developing cardiovascular disease, cancer, hypertension and obesity. Therefore, several studies have focused on the manufacture of healthier products, among which the products with less synthetic additives have stood out. In this context, the aim of this study was to evaluate the antioxidant activity of plant-derived commercial extracts on meat raw materials (mechanically separated poultry - MSP) and restructured meat product made with different raw materials (beef or pork or chicken or MSP). The natural extracts concentrations were 0.125, 0.25, 0.5, and 1.0% w / w. The extracts were characterized for phenolics content, total flavonoids, and antioxidant activity using ORAC, DPPH, and ABTS assays. Lipid oxidation was evaluated by measuring thiobarbituric acid reactive substances - TBARS. The chilled (4 °C) fresh raw material was evaluated at days 0, 2, 4, 6, 8, and 10, while the cooked product (4 °C) was evaluated at days 0, 3, and 6, and the fresh frozen product (-18 °C) was evaluated at days 0, 30 and 60 of storage. All natural extracts exhibited antioxidant activity, especially the grape seed and green tea extracts. In the MSP, all extracts presented antioxidant potential, and the pomegranate extract was less effective and therefore has not been used in the product formulation. The green tea extract was the most effective against oxidation in cooked and raw burgers. However, the grape seed, rosemary, and mate extracts also increased shelf life of the cooked burgers. With respect to the frozen hamburgers, the shelf life was also increased by grape seed and rosemary extracts. A higher antioxidant potential of the natural extracts was observed when compared to the synthetic antioxidant BHT. The results suggest that despite commercial plant-derived extracts can be used as natural antioxidants in meat products, sensory studies are necessary to enable their addition. With regard to lipid oxidation, it is possible to use commercial plant-derived extracts in meat products, improving nutritional quality / Mestrado / Tecnologia de Alimentos / Mestra em Tecnologia de Alimentos
238

Ação de extratos botânicos no controle da formiga cortadeira Atta sexdens rubropilosa (Hym: Formicidae) / Botanical extracts action to control of the leaf-cutting ants Atta sexdens rubropilosa (Hym: Formicidae)

Leite, Rafael Gervasoni Ferreira 17 September 2015 (has links)
Submitted by Michele Mologni (mologni@unoeste.br) on 2017-06-09T18:06:27Z No. of bitstreams: 1 Rafael Gervasoni Ferreira Leite.pdf: 551041 bytes, checksum: 2d93c9ae3fe4163e7faba1743109a057 (MD5) / Made available in DSpace on 2017-06-09T18:06:27Z (GMT). No. of bitstreams: 1 Rafael Gervasoni Ferreira Leite.pdf: 551041 bytes, checksum: 2d93c9ae3fe4163e7faba1743109a057 (MD5) Previous issue date: 2015-09-17 / The control of leafcutter ants is constant in agroecosystems, in which, among the different methods adopted, the chemical one (toxic baits) is the most used. Substances that are extracted from plants, as insecticides, have many advantages when compared to the use of synthetic products. This project’s objective was to evaluate the insecticidal and/or fungicidal potential of the plants Asclepias curassavica, Rosmarinus officinalis and Equisetum ssp. in the control of the leaf-cutting ants Atta sexdens rubropilosa. We made use of 40 colonies of Atta sexdensbred in a laboratory. The plants were collected, dried in a high temperature test chamber for 48 hours, grinded in a Wiley mill and macerated in ethanol 96º up to exhaustion. After being filtered, the product obtained was evaporated under reduced pressure for the production of ethanolic extracts. We conducted reagent acceptance tests, topical application of ethanolic extracts at 4% on the back of the ants and topical application of baits made with plant extracts at 4%. All of the plant extracts adopted affected the de development of the fungi garden negatively. Asclepias-curassavica-based baits provoked the mortality of 22.5% of the colonies in a 7-day period. / O controle de formigas cortadeiras é constante nos agroecossistemas sendo empregados diferentes métodos, onde o químico (iscas tóxicas) é o mais utilizado. Substâncias extraídas de plantas, na qualidade de inseticidas, têm inúmeras vantagens quando comparado ao emprego dos sintéticos. A pesquisa teve como objetivo avaliar o potencial inseticida e/ou fungicida das plantas Asclepias curassavica (falsa-erva-de-rato), Rosmarinus officinalis (alecrim) e Equisetum ssp. (cavalinha) no controle de formigas cortadeiras Atta sexdens rubropilosa. Foram utilizadas 40 colônias de Atta sexdens rubropilosa mantidas em laboratório. As plantas foram colhidas, secas em estufa de ar circulante durante 48 horas, trituradas em moinho tipo Willye e maceradas em etanol 96º até exaustão. Após a filtragem, o produto obtido foi evaporado sob pressão reduzida para obtenção dos extratos etanólicos. Foram realizados teste de aceitação do reagente, aplicação tópica dos extratos etanólicos dos vegetais a 4% no dorso das formigas e aplicação de iscas confeccionadas com extratos vegetais a 4%. Todos os extratos vegetais utilizados influenciaram negativamente o desenvolvimento do jardim de fungo. Iscas produzidas a base de Asclepias curassavica provocaram mortalidade de 22,5% das colônias num período de 7 dias.
239

Uso de extratos vegetais como promotores do crescimento em frangos de corte / Use of plant extracts as growth promoters for broiler chickens

Marina Sígolo Rodrigues Barreto 02 July 2007 (has links)
Nas últimas décadas, a produção de carne de frango vem se intensificando por expressivos avanços tecnológicos. Nutricionalmente, os promotores de crescimento antimicrobianos (antibióticos e quimioterápicos) foram essenciais, beneficiando o desempenho e a eficiência alimentar, quando utilizados como aditivos nas dietas, em doses subterapêuticas. Apesar da comprovada contribuição no desempenho das aves, os antibióticos promotores de crescimento passaram a ser vistos como fatores de risco para a saúde humana, devido ao potencial desenvolvimento da resistência bacteriana cruzada em humanos. Recentemente, têm sido desenvolvidas diversas alternativas aos antibióticos promotores de crescimento, incluindo probióticos, prebióticos, ácidos orgânicos, enzimas e extratos vegetais. Seguindo essa tendência, este estudo teve o objetivo de avaliar a eficácia do uso de extratos vegetais como alternativas aos antimicrobianos promotores de crescimento em dietas de frangos de corte. Foram realizados dois experimentos com frangos de corte para avaliar os efeitos de diferentes extratos vegetais no desempenho, na energia metabolizável da dieta e na morfometria dos órgãos. O experimento de desempenho envolveu 1200 frangos de corte machos criados em galpão experimental no período de 1 a 42 dias de idade, separados em grupos de 40 aves por boxe. O delineamento experimental foi em blocos casualizados, sendo seis tratamentos e cinco repetições. O ensaio de metabolismo contou com 96 frangos machos em crescimento alojados em gaiolas metabólicas para coleta total de excretas, foram seis tratamentos e quatro repetições em delineamento interiramente casualizado. Ambos os experimentos receberam os mesmos tratamentos: dieta controle (DC); DC + 10 ppm de Avilamicina; DC + 1000 ppm de extrato de orégano; DC + 1000 ppm de extrato de cravo; DC + 1000 ppm de extrato de canela e DC + 1000 ppm de extrato de pimenta vermelha. Os produtos à base de extratos vegetais consistiram de microencapsulados contendo 20% do óleo essencial. As variáveis determinadas foram: peso vivo, ganho de peso, consumo de ração, conversão alimentar, mortalidade, energia metabolizável aparente (EMAn) das dietas e peso relativo dos órgãos. Os resultados foram submetidos à análise de variância e as médias comparadas pelo teste de Tukey. Não foi possível observar diferenças significativas (P>0.05) entre os tratamentos propostos para as variáveis de desempenho analisadas em todo o período de criação das aves. Da mesma maneira, a suplementação dos extratos nas dietas não interferiu (P>0.05) nos valores de EMAn das mesmas. A morfometria dos órgãos, em geral, também não foi alterada pela utilização dos extratos vegetais. Pôde ser observado que, os animais que receberam ração controle apresentaram maior peso relativo do fígado em relação aos demais tratamentos, diferindo significativamente (P<0.05) das aves alimentadas com a dieta suplementada com extrato de pimenta, que foi o menor valor observado. / Broiler meat production has experienced expressive technological improvements in the last decades. Nutritionally, the antimicrobial growth promoters (antibiotics and chemotherapeutics) contributed to that, when utilized as feed additives. These antimicrobials are very effective in performance improvement, but there are human health risks associated to their use because of the possibility of development of bacterial cross resistance. In recent years, several alternatives to the antibiotic growth promoters have been proposed including probiotics, prebiotics, organic acids, enzymes and plant extracts. In this context, the objective of the present study was to evaluate the efficacy of plant extracts as alternative growth promoters to the antibiotics as feed additives in chicken diets. Two experiments were conducted to determine the effects of different plant on the metabolizable energy of the diet and performance and organ morphometry of broiler chickens. The performance trial involved 1,200 male chicks raised from 1 to 42 days of age, in groups of 40 birds per pen, in a experimental poultry house. A randomized complete block design, with 6 treatments and 5 blocks, was used. In the metabolism trial, 96 chickens in the grower period were allotted to battery cages and total excreta collection was conducted with 6 treatments and 4 replicates in a completely randomized design. The treatments for both experiments were: Corn-soybean meal control diet (C); C + 10 ppm Avilamycin; C + 1,000 ppm oregano extract; C + 1,000 ppm clove extract; C + 1,000 ppm cinnamon extract; C + 1,000 ppm red pepper extract. The plant extract products added consisted of microencapsulated preparations containing 20% essential oil. The variables evaluated were liveweight, weight gain, feed intake, feed conversion, mortality, apparent metabolizable energy (AMEn) of the diets and organ weights. The results were statistically analyzed by ANOVA and means compared using Tukey&#39;s test. It was not detected any significant (P>0.05) difference among the treatments for the performance variables of the chickens along the growth period. Likewise, the plant extracts supplementation did not affect the AMEn of the diets (P>0.05). Organ morphometry was also, in general, not influenced by the additives. The only significant effect was a higher liver relative weight of the control birds (P<0.05) compared to the red pepper fed birds.
240

Desempenho produtivo e microbiota intestinal de frangos de corte suplementados com ß-ácidos do lúpulo (Humulus lupulus) após desafio com Eimeria acervulina e E. tenella / Performance and intestinal microbiota of broiler chickens supplemented with hops ß-acids (Humulus lupulus) following challenge with Eimeria acervulina and E. tenella

Cristiano Bortoluzzi 04 February 2014 (has links)
Este estudo teve por objetivos avaliar diferentes níveis de suplementação de ?-ácidos do lúpulo como aditivos de rações para frangos de corte sobre o desempenho e a manutenção do equilíbrio da microbiota intestinal após desafio com Eimeria. No experimento 1, foram alojados 1440 pintos de corte da linhagem Cobb 500, no período de 1 a 42 dias de idade, com 6 tratamentos e 6 repetições. Os tratamentos utilizados foram: controle negativo, ração sem antimicrobiano; controle positivo, ração com 30 mg/kg de bacitracina de zinco e rações com 30, 60, 120 ou 240 mg/kg de ?-ácidos do lúpulo, compondo 4 tratamentos adicionais. Os ?-ácidos foram microencapsulados com 30%de extrato. As rações foram formuladas à base de milho e farelo de soja, com inclusão de 5% de farelo de trigo e 5% de farinha de penas e vísceras. Aos 7 dias de idade todas as aves foram vacinadas contra coccidiose. As aves e as rações foram pesadas semanalmente para cálculo de desempenho. No experimento 2, foram alojados 1440 pintos de corte da linhagem Ross 308, no período de 1 a 42 dias de idade, com 6 tratamentos e 6 repetições. Os tratamentos foram: controle negativo, dieta basal; controle positivo, ração com 30 mg/kg de bacitracina de zinco; controle negativo mais desafio; controle positivo mais desafio; controle negativo suplementado com 30 mg/kg de ?-ácidos mais desafio; controle negativo suplementado com 240 mg/kg de ?-ácidos mais desafio. As rações foram formuladas à base de milho e farelo de soja com inclusão de 5% de farinha de penas e vísceras. Aos 14 dias de idade, as aves dos tratamentos 3, 4, 5 e 6 foram desafiadas, via oral, com 2x105 e 5x104 oocistos de Eimeria acervulina e E. tenella, respectivamente. As aves e as rações foram pesadas semanalmente para obtenção dos dados de desempenho. Aos 21 e 35 dias de idade das aves, coletou-se o conteúdo do intestino delgado e cecos das aves para análise da microbiota intestinal, com auxílio de técnicas moleculares. No experimento 1, aos 21 dias de idade as aves os tratamentos com 30 ou 60 mg/kg de ?-ácidos apresentaram desempenho semelhante às do controle positivo. Aos 42 dias houve melhora na conversão alimentar das aves recebendo 30 e 240 mg/kg de ?-ácidos ou antimicrobiano. No segundo experimento, a coccidiose causou significativa redução no desempenho das aves e nenhum dos aditivos utilizados foi capaz de reverter esta situação. Houve aumento de bactérias do gênero Clostridium no intestino delgado aos 21 dias, em consequência do desafio, entretanto, o maior nível de ?-ácidos reduziu esta população. Aos 35 dias de idade a infecção de coccidiose não alterou a comunidade bacteriana do intestino delgado, mas nos cecos houve aumento do gênero Bacteroides.Os ?-ácidos possuem potencial para serem utilizados nas dietas de frangos de corte em situações de baixo desafio, e podem auxiliar no controle da proliferação de Clostridium, embora ineficazes contra a Eimeria. / The objective was to evaluate increasing level of hops ?-acids in the feed on performance of broiler chickens. A pen trial using 1440 one-day old chickens, from 1 to 42 days, with 6 treatments and 6 replicates was conducted (Experiment 1). The experimental treatments were: negative control, basal diet; positive control, basal diet supplemented with zinc bacitracin, 30 mg/kg; and basal diet supplemented with 30, 60, 120 or 240 mg/kg of hops ?-acids, for 4 additional treatments. The corn soybean meal basal diet was formulated with inclusion of 5% poultry by-product meal and 5% wheat bran. At 7 days of age all birds were vaccinated against coccidiosis. The chickens and the feed were weighted weekly to calculate the performance. In the second experiment, the objective was to evaluate the supplementation of hops ?-acids on performance and the balance of intestinal microbiota of broilers, following challenge with Eimeria acervulina and E. tenella. A pen trial using 1440 one-day-old chickens, from 1 to 42 days, with 6 treatments and 6 replicates was conducted. The experimental treatments were: negative control, basal diet; positive control, basal diet supplemented witn zinc bacitracin, 30 mg/kg; negative controle + challenge; Positive control + challenge; negative control supplemented with 30 mg/kg of hops ?-acids + challenge; negative control supplemented with 240 mg/kg of hops ?-acids + challenge. The corn soybean meal basal diet was formulated with inclusion of 5% poultry byproduct meal. At 14 days of age, the birds in treatments 3, 4, 5 and 6 were challenged with 2x105 and 5x104 oocists of Eimeria acervulina and E. tenella, respectively. The chickens and the feed were weighted weekly to calculate the performance. At 21 and 35 days of age, the small intestine and ceca content was collected to analyze the intestinal microbiota, using molecular techniques. In the first experiment, at 21 days of age the treatment with 30 or 60 mg/kg of ?-acids had the same performance of chickens in positive control. At 42 days, the treatments containing 30 or 240 mg/kg of ?-acids and positive control had improved feed conversion. In the second experiment, there was worse performance in broilers chickens challenged with coccidiosis and the additives were not able to oppose this situation. There was increase in the Clostridium population in the small intestine at 21 days, due to challenge, however, the highest level of ?-acids decreasead this genus. At 35 days, the coccidiosis did not alter the bacterial community in the small intestine, although the ceca had higher level of Bacteroides. The hops ?-acids have the potential to be used in the diets of broiler chickens, under low level of challenge, and to proliferation of Clostridium, although ineffective against Eimeria.

Page generated in 0.0455 seconds