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  • 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.
21

Efeitos da exposição prolongada de aflatoxina B1 e fumonisina B1 em codornas: avaliação de parâmetros de desempenho e de qualidade dos ovos / Effects of prolonged intoxication of aflatoxin B1 and fumonisin B1 in laying Japanese quail: evaluation of productivity and egg quality

Ogido, Rony 27 June 2003 (has links)
O projeto avaliou os efeitos da aflatoxina B1 (AFB1) e fumonisina B1 (FB1), isoladas e associadas, sobre a produtividade e a qualidade dos ovos de codornas poedeiras (Coturnix coturnix japonica). Duzentas e oitenta e oito aves, adquiridas com idade de 8 semanas, foram subdivididas em 6 grupos experimentais (48 aves por grupo) e submetidas a 6 tipos de tratamentos, constituídos por rações contendo AFB1 e FB1 nas concentrações: (0 AFB1+0 FB1), (0 AFB1+10 mg/kg FB1), (50 &microg/kg AFB1+0 FB1), (50 µg/kg AFB1+10 mg/kg FB1), (200 µg/kg AFB1+0 FB1), e (200 µg/kg AFB1+10 mg/kg FB1). As aves foram alimentadas durante 140 dias (5 ciclos de 28 dias). Os parâmetros de produtividade foram avaliados semanalmente, através do consumo de ração, peso dos ovos, índice de conversão alimentar e curva de produção. A qualidade dos ovos foi avaliada a cada ciclo de 28 dias, cada ovo produzido nesse dia foi analisado individualmente para a determinação do valor de unidade Haugh, gravidade específica e percentual do peso da casca. Ao final do 5º período experimental, o peso médio dos ovos foi significativamente menor (p < 0,05) nas aves alimentadas com 10 mg FB1/kg, 50 &microg/kg AFB1, 200 µg/kg AFB1 e com o tratamento de associação de 10 mg FB1/kg + 50 µg/kg AFB1. Em relação à produção de ovos, as codornas alimentadas com 10 mg FB1/kg apresentaram uma diminuição significativa (p < 0,05), ao final do 3º, 4º e 5º ciclos. O consumo médio diário de ração foi significativamente menor (p< 0,05) nas aves alimentadas com 10 mg FB1/kg, ao final do 4º e 5º ciclos, enquanto que os níveis de 50 ou 200 µg/kg AFB1 provocaram uma diminuição significativa (p < 0,05), ao final do 5º período experimental. Ao final do 1º, 2º e 5º ciclos, o consumo médio de ração foi significativamente menor (p< 0,05) nas aves tratadas com 10 mg FB1/kg + 50 µg/kg AFB1. Os índices de conversão alimentar e os valores de Unidades Haugh não foram afetados (p > 0,05) pelos tratamentos. A gravidade específica dos ovos foi significativamente menor (p < 0,05) ao final do 5º ciclo, nas aves tratadas com 10 mg FB1/kg + 200 µg/kg AFB1. Observou-se uma diminuição significativa (p < 0,05) na porcentagem do peso de casca, nas aves tratadas com 10 mg FB1/kg ao final do 1º ciclo, entretanto, houve um aumento significativo (p < 0,05) nos tratamentos com 200 µg/kg AFB1 e também com 10 mg/kg FB1 + 50 µg/kg AFB1 ao final do 1º ciclo. Já ao final do 5º ciclo, o aumento na porcentagem de peso de casca (p < 0,05) ocorreu somente nas aves tratadas com 10 mg/kg FB1 + 200 µg/kg AFB1. Os resultados demonstraram que a administração prolongada de FB1 e AFB1, isoladas ou associadas nos níveis utilizados no presente experimento, pode causar prejuízos econômicos aos produtores de ovos de codornas. / This study evaluated the individual and combined effects of aflatoxin B1 (AFB1) and fumonisin B1 (FB1) on egg quality and performance of laying Japanese quail (Coturnix coturnix japonica). Two hundred twenty-eight birds were purchased at 8 week of age and randomly distributed into 6 experimental groups and given rations containing AFB1 and FB1 at the following levels: (0 AFB1+0 FB1), (0 AFB1+10 mg/kg FB1), (50 &microg/kg AFB1+0 FB1), (50 &microg/kg AFB1+10 mg/kg FB1), (200 &microg/kg AFB1+0 FB1), e (200 &microg/kg AFB1+10 mg/kg FB1). The birds were fed for 140 days (5 28-day laying periods). Each treatment consisted of four replicates of twelve quail. Egg production and individual egg weight were checked daily. Feed consumption and feed utilization were determined weekly. Eggs laid in the last day of each 28-day laying period were collected and submitted to individual analysis for specific gravity, Haugh units and percent egg shell. Results showed that average egg weight at the end of the fifth cycle was significantly lower (p < 0,05) for groups fed 10 mg FB1/kg, 50 &microg/kg AFB1, 200 &microg/kg AFB1 and also for the group fed 10 mg FB1/kg + 50 &microg/kg AFB1. Average egg production significantly decreased (p < 0,05) for groups fed 10 mg FB1/kg by the end of the third, fourth and fifth cycles. Feed consumption was significantly lower (p < 0,05) for group exposed to 10 mg FB1/kg, by the end of fourth and fifth cycles, whereas birds fed 50 or 200 &microg/kg AFB1 showed a significant decrease (p < 0,05) on feed consumption, by the end of fifth cycle. Birds exposed to 10 mg FB1/kg + 50 &microg/kg AFB1 also showed lower values (p < 0,05) of feed consumption, by the end of first, second and fifth cycles. Feed utilization and Haugh units were not affected (p > 0,05) by AFB1 and FB1. Average egg specific gravity was significantly lower (p < 0,05) for group fed 10 mg FB1/kg + 200 &microg/kg AFB1, by the end of fifth cycle. Percent egg shell was significantly lower (p < 0,05) for group exposed to 10 mg FB1/kg, by the end of the first cycle, however, birds exposed to 200 &microg/kg AFB1 and also to 10 mg/kg FB1 + 50 &microg/kg AFB1, showed a significantly increase (p < 0,05) of percent egg shell, by the of the first cycle. Percent egg shell was significantly higher (p < 0,05) for group fed 10 mg/kg FB1 + 200 &microg/kg AFB1 , by the end of fifth cycle. The results obtained in the present study showed that the prolonged administration of FB1 and AFB1, singly or combined at the levels checked, may cause economic losses to the quail egg producers.
22

Determinação de biomarcadores de aflatoxina B1 e aplicabilidade na avaliação da eficiência de adsorventes em frangos de corte / Determination of Aflatoxin B1 biomarkers and its aplicability on efficience avaliation of adsorbents in broiler chickens

Carão, Agatha Cristina de Pinho 29 February 2016 (has links)
As aflatoxinas são metabólitos secundários produzidos por fungos toxigênicos das espécies Aspergillus flavus, A. parasiticus e A. nomius. São amplamente encontradas em matérias-primas de rações animais, em especial o milho, e têm a capacidade de levar a quadros clínicos agudos ou crônicos de aflatoxicose, caracterizados por, desde a morte por hepatite aguda até a diminuição do desempenho zootécnico por diminuição de peso ou consumo de ração. A aflatoxina B1 tem sido considerada o metabólito mais perigoso, uma vez que possui alto poder hepatotóxico, além de ser mutagênica e carcinogênica. Atualmente a ciência trabalha rumo à descoberta de substâncias que sejam indicadoras confiáveis de contaminação por componentes tóxicos em homens e em animais, os chamados biomarcadores, que medem uma mudança celular, biológica ou molecular em um meio biológico (tecidos humanos, células ou fluídos) que fornecem informação a respeito de uma doença ou exposição a uma determinada substância. Sua detecção pode auxiliar na identificação, no diagnóstico e no tratamento de indivíduos afetados que podem estar sob risco, mas ainda não exibem os sintomas. Sendo assim, com o auxílio de análises que confirmem a patogenicidade da aflatoxina B1 (determinação da atividade de enzimas hepáticas, da avaliação da função renal, de hematologia, da dosagem de minerais séricos e da avaliação de desempenho zootécnico), o objetivo deste trabalho foi avaliar a aplicabilidade da determinação de resíduos hepáticos de aflatoxinas e do aduto sérico AFB1-lisina na avaliação da eficiência de adsorventes em frangos de corte. Utilizou-se 240 pintos de 1 dia, machos, de linhagem Cobb 500&reg;, distribuídos aleatoriamente em 4 dietas experimentais: Controle Negativo: Ração Basal (RB); RB &#43; 0,5% de adsorvente ((aluminosilicato de cálcio e sódio hidratado/HSCAS); RB &#43; 0,5% de adsorvente &#43; 500 &micro;g de AFB1/kg de ração e; RB &#43; 500 &micro;g de AFB1/kg de ração.Os resultados experimentais mostram que o efeito deletério da AFB1, na concentração utilizada, é mais pronunciado que os efeitos protetores do HSCAS sobre os parâmetros de saúde dos animais. Não houve ação efetiva do adsorvente utilizado sobre quase nenhuma variável estudada, apenas para a redução das lesões histopatológicas em fígado, na redução da concentração de gama-glutamiltransferase (GGT), fósforo e aumento da contagem de hemáceas aos 21 dias de idade. Porém, influenciou positivamente a redução de resíduos hepáticos de aflatoxina G1 aos 21 dias e as concentrações de AFB1-lisina sérica aos 21 e aos 42 dias de idade. Estes dados são importantes porque permite concluir que, embora sintomatologicamente o HSCAS não tenha exercido função efetiva, molecularmente foi capaz de mostrar de eficácia sobre os alguns biomarcadores de aflatoxinas no organismo das aves / Aflatoxins are secondary metabolites produced by toxigenic fungi of the species Aspergillus flavus, A. parasiticus and A. nomius. They are widely found in raw materials of animal feed, in particular corn, and have the ability to lead to clinical cases of acute or chronic aflatoxicosis, characterized by acute hepatites leading to death until lower performance by decreased weight or feed intake. Aflatoxin B1 has been considered the most dangerous metabolite, since it has high hepatotoxic power, besides being mutagenic and carcinogenic. Nowadays science works toward the discovery of substances that are reliable indicators of contamination by toxic components in humans and animals, called biomarkers, which measure a cell change, biological or molecular in a biological medium (human tissues, cells or fluids) that provide information regarding a disease or exposure to a particular substance. Its detection can assist in the identification, diagnosis and treatment of affected individuals who may be at risk, but still do not exhibit symptoms. Thus, with the help of analysis that confirm aflatoxin B1 pathogenicity (determination of liver enzymes activity, assessment of renal function, hematology, dosage of serum minerals and evaluation of animal performance), the objective of this work was to evaluate the applicability of the determination of aflatoxin liver residues and serum AFB1-lysine adduct in the evaluation of the adsorbents efficiency in broiler chickens. Two hundred and fourty day-old male chicks, Cobb 500&reg; lineage, were randomly distributed into 4 experimental diets: Negative Control: Basal Feed (BF); BF &#43; 0.5% adsorbent (hydrated sodium calcium aluminosilicate/HSCAS); RB &#43; 0.5% adsorbent &#43; 500 &micro;g AFB1/kg of feed; and RB &#43;500 &micro;g AFB1/kg of feed. The experimental results show that the deleterious effect of AFB1, at the concentration used, is more pronounced that the protective effects of HSCAS on animal health parameters. There was no effective action of the adsorbent used on almost any variable studied, only for the reduction of the histopathological lesions in the liver, reduction of gamma-glutamyltransferase (GGT) and phosphorus concentration, and increased count of red blood cells at 21 days. However, influenced positively the reduction of aflatoxin G1 liver residues at 21 days and the concentrations of serum AFB1-lysine at 21 and 42 days. These are important data because they allow to conclude that, although symptomatically the HSCAS has not exercised effective function, molecularly was able to show some efficacy on aflatoxin biomarkers in the birds body
23

Mutação pontual do códon 249 do TP53 no carcinoma hepatocelular / Mutation of TP53 codon 249 in the hepatocellular carcinoma

Nogueira, Jeronimo de Alencar 01 February 2008 (has links)
Mutação 249Ser no TP53 no Carcinoma Hepatocelular (CHC), frequente em países da África e Ásia, é uma evidência molecular de exposição à aflatoxina. O objetivo deste estudo é analisar a freqüência de 249Ser em 74 amostras de CHC no Brasil. A mutação foi analisada por RFLP e sequenciamento. A presença de vírus da hepatite B (VHB) foi analisada por PCR em tempo real. 249Ser foi encontrada em 13/74 (28%) e VHB em 13/74 (16%). A mutação foi encontrada em maior freqüência em tumores indiferenciados (OR = 2,415, IC = 1,001 - 5,824). O tamanho médio de tumores com 249Ser foi de 9,4 cm contra 5,5 cm de amostras sem a mutação (p=0,012). Não foi encontrada relação entre VHB e 249Ser. Os resultados indicam que 249Ser é um fator importante na carcinogênese do CHC no Brasil sendo associada à uma forma maior e menos diferenciada de tumor. / TP53 249Ser mutation has been proved a molecular evidence for aflatoxin-related Hepatocellular Carcinoma (HCC) and is frequent in Africa and Asia. The aim of our study was to analyze the frequency of 249Ser mutation in HCC from Brazil. We studied 74 samples of paraffin embedded HCC. 249Ser mutation was analyzed by RFLP and sequencing. Presence of HBV DNA was determined by Real-Time PCR. 249Ser was found in 21/74 (28%) samples while HBV DNA was found in 13/74 (16%). Poorly differentiated HCC was more likely to have 249Ser mutation (OR = 2.415, IC = 1.001 - 5.824). The mean tumor size of 249Ser HCC was 9.4 cm versus 5.5cm on wild type (p=0.012). HBV DNA was not related with 249Ser. Results indicate that 249Ser is an important factor of HCC carcinogenesis in Brazil and is associated with large and poorly differentiated tumors.
24

An?lises micol?gicas e micotoxicol?gicas em ra??es de frangos de corte no munic?pio de S?o Jos? do Vale do Rio Preto-RJ. / Mycological and mycotoxicological survey in poultry feeds from S?o Jos? do Vale do Rio Preto-RJ.

Oliveira, Glenda Ribeiro de 24 November 2006 (has links)
Made available in DSpace on 2016-04-28T20:17:26Z (GMT). No. of bitstreams: 1 2006- Glenda Ribeiro de Oliveira.pdf: 475801 bytes, checksum: 8ca6884856073fd041daad94f50fca0e (MD5) Previous issue date: 2006-11-24 / The intake of mycotoxin-contamined feeds may lead to nutrient losses and can have adverse effects on animal health and on productivity. The aims of this study were: 1) to determine the mycobiota present in poultry feed samples, obtained from three factories in the region of S?o Jos? do Vale do Rio Preto, RJ, Brazil; 2) to evaluate the natural occurrence of aflatoxin B1 (AFB1), fumonisin B1 (FB1) and zearalenone using the method enzyme linked immunosorbent assay (ELISA) competitive, commercial kits of Beacon Analytical Systems Inc, USA and 3) to verify the data results by the ELISA to AFB1 and FB1 comparing them with the high precision liquid chromatography methodology (HPLC) Fungal counts were similar between all culture media tested (103 CFU.g-1). Penicillium spp. (41,26%) was the most prevalent genus followed by Aspergillus spp. (33,33%) and Fusarium spp. (20,63%). Aflatoxin B1 was found in 66,27% samples examined by ELISA kits and values ranged between 2 and 21&#956;g.kg-1. Fumonisin B1 was found in 97,87% and levels ranged between 0,3 and 9,1&#956;g.g-1, cooccurring with aflatoxin B1 in 66,7% of the samples. Low concentrations of zearalenone were found (<1 &#956;g.g-1) in 77,1% poultry feed samples. Correlation between the ELISA kits (AFB1 and FB1) and the HPLC analysis was obtained. Values were r2= 0,9922 and r2=0,9823, respectively. In general, the highest mycotoxin levels were found during the hottest month of sampling. The present study shows the simultaneous occurrence of two carcinogenic mycotoxins, aflatoxin B1 and fumonisin B1 together with another Fusarium mycotoxin (zearalenone) in feed intended for poultry consumption. Many samples contained AFB1 levels near the maximum permissible and it could affect young animals. A synergistic toxic response is possible in animals under simultaneous exposure. / A ingest?o de ra??es contaminadas por micotoxinas pode acarretar perdas no seu valor nutritivo e causar efeitos adversos ? sa?de animal e ? produtividade. Os objetivos desse estudo foram: 1)estabelecer a freq??ncia e a preval?ncia da micobiota presente em amostras de ra??es de frangos de corte provenientes de tr?s f?bricas em S?o Jos? do Vale do Rio Preto-RJ, 2)verificar a ocorr?ncia natural de aflatoxina B1 (AFB1), fumonisina B1 (FB1) e zearalenona (ZEA), utilizando a t?cnica biol?gica de imunoensaios-ELISA competitivo, com kits comerciais (Beacon Analytical Systems Inc, USA) e 3)verificar os resultados obtidos pelo m?todo de ELISA, comparando-os com a t?cnica de Cromatografia L?quida de Alta Efici?ncia (CLAE) para AFB1 e FB1. A contagem dos prop?gulos f?ngicos foi similar entre todos os meios de cultura testados (103 UFC g-1). Penicillium spp (41,26%) foi o g?nero de maior preval?ncia seguido por Aspergillus spp (33,33%) e Fusarium spp. (20,63%). Aflatoxina B1 foi encontrada em 66,27% das amostras analisadas pelos kits de ELISA,com valores variando entre 2 e 21&#956;g.kg-1. Fumonisina B1 foi encontrada em 97,87% e os valores variaram entre 0,3 e 9,1&#956;g.g-1, co-ocorrendo com aflatoxinaB1 em 66,7% das amostras. Baixas concentra??es de zearalenona foram encontradas (< 1&#956;g.g-1)em 77,1% das amostras de ra??o. Foi obtida correla??o entre os kits de ELISA (AFB1 e FB1) e as an?lises em CLAE, com valores de r2= 0,9922 e 0,9823, respectivamente. Em geral, os maiores n?veis de micotoxinas foram encontrados durante os meses mais quentes do ano. O presente estudo mostra a ocorr?ncia simult?nea de duas micotoxinas carcinog?nicas, AFB1 e FB1, juntamente com outra Fusarium micotoxina (zearalenona) em ra??es destinadas ao consumo de frangos. Algumas amostras apresentaram n?veis de AFB1 pr?ximos ao m?ximo permitido, o que poderia afetar aves jovens. Uma resposta t?xica sin?rgica ? poss?vel em animais sob exposi??o simult?nea.
25

Potencijal biosinteze aflatoksina B1 u različitim vrstama Triticum spp. / Potential biosynthesis of aflatoxin B1 in different species of Triticum spp.

Krulj Jelena 11 January 2019 (has links)
<p style="text-align: justify;">Prisustvo plesni i mikotoksina u hrani predstavlja vi&scaron;estruku opasnost, kako sa aspekta bezbednosti hrane, tako i sa aspekta globalne trgovine. Učestalost i intenzitet pojave plesni na uzorcima zrna hlebne p&scaron;enice i spelte prikupljenih u regionu Vojvodine određeni su nakon žetve tokom trogodi&scaron;njeg perioda (2015-2017). Istraživanja su obuhvatila identifikaciju i karakterizaciju 38 izolata A. flavus primenom polifaznog pristupa koji uključuje klasične mikrobiolo&scaron;ke i molekularne metode. Ispitivanjem potencijala biosinteze AFB<sub>1</sub> izolata A. flavus utvrđeno je da su dva izolata poreklom sa zrna hlebne p&scaron;enice pokazala aflatoksigeni potencijal. Ve&scaron;tačka inokulacija različitih Triticum vrsta: hlebne p&scaron;enice, spelte, korasan i hibrida p&scaron;enice toksigenim izolatama izvr&scaron;ena je u fazi cvetanja u cilju poređenja otpornosti ovih vrsta na pojavu A. flavus i produkciju AFB<sub>1</sub>. Visok nivo AFB<sub>1</sub> (256 &mu;g/kg) je kvantifikovan samo u zrnu spelte, dok kod drugih Triticum vrstama, zrno nije bilo kontaminirano AFB<sub>1</sub> (&lt;LOD). Određivanjem fizičko-hemijskih karakteristika plevičastih omotača Triticum vrsta potvrđen je njihov potencijalni uticaj na rast i razvoj A. flavus i biosintezu AFB<sub>1</sub>. Efekti različitih temperatura (15, 23, 30 i 37&deg;C) i aktivnosti vode (0,85; 0,90; 0,95 i 0,99) na biosintezu AFB<sub>1</sub> ispitani su na ve&scaron;tački inokulisanim uzorcima spelte sa plevičastim omotačima kao i prethodno olju&scaron;tenim zrnima. Optimalni uslovi za biosintezu tj. uslovi pri kojima je ostvaren najveći prinos AFB<sub>1</sub> bili su temperatura 30 &deg;C i aw 0,99 u svim tipovima uzoraka (zrna spelte inkubirana bez plevičastih omotača - ZBPO, plevičasti omotači - PO i zrna nakon lju&scaron;tenja tj. olju&scaron;tena zrna - OZ). Rezultati su pokazali da je prisustvo plevičastih omotača bilo za&scaron;titna barijera za razvoj infekcije i akumulaciju AFB<sub>1</sub> u zrnu. Matematički modeli, razvijeni primenom faktora sa visokom značajno&scaron;ću kao &scaron;to su temperatura skladi&scaron;tenja i aktivnost vode, mogu biti kori&scaron;ćeni u predviđanju akumulacije AFB<sub>1</sub> u zrnu spelte &scaron;to predstavlja ključni korak u proceni rizika. Ispitivanjem uticaja različitih nivoa kontaminacije spelte AFB<sub>1</sub> u poređenju sa kontrolnim nekontaminiranim uzorkom ukazano je na smanjenje određenih parametara tehnolo&scaron;kog kvaliteta i potencijalne gubitke pecivnih svojstava speltinog bra&scaron;na pri sadržaju AFB<sub>1</sub> od&nbsp;&nbsp; 50 &mu;g/kg i 250 &mu;g/kg.</p> / <p>The presence of fungi and mycotoxins in food presents a multiple risk, both from the aspect of food safety and from the aspect of global trade. The frequency and incidence of mycobiota on common wheat and spelt grains samples collected in the region of Vojvodina were determined after harvest during the three-year period (2015-2017). The research covered the identification and characterization of 38 A. flavus isolates using a polyphase approach including classical microbiological and molecular methods. Testing the A. flavus isolates for AFB<sub>1</sub> biosynthesis, it was found that two isolates originating from wheat grains possess the aflatoxigenic potential. Artificial inoculation of different Triticum species: common wheat, spelt, khorasan and hybrid wheat with toxigenic isolates was carried out in the flowering stage in order to compare the resistance of these species to the occurrence of A. flavus and the production of AFB<sub>1</sub>. The highest AFB<sub>1</sub> level (256 &mu;g/kg) was determined only in the dehulled spelt grains, in comparison to other species where AFB<sub>1</sub> was not detected in dehulled grains. In order to investigate the impact of wheat hulls on development of A. flavus, including the biosynthesis of toxic fungal metabolites, physico-chemical and structural properties of different Triticum spp. hulls were characterized. The effects of different temperatures (15, 23, 30 and 37 &deg; C) and water activity (0.85; 0.90; 0.95 and 0.99) on AFB<sub>1</sub> biosynthesis were examined on artificially inoculated hull-less as well as hulled spelt grains. The optimal conditions for AFB<sub>1</sub> biosynthesis (the conditions in which the highest AFB<sub>1</sub> yield was achieved) were temperature 30 &deg;C and 0.99 aw in the all tested spelt samples (hull-less grain, dehulled grains and hulls). Accumulation of AFB<sub>1</sub> was significantly higher in hull-less than in dehulled grains that implicate the protective effect of spelt hulls. Mathematical models, developed using high-significance factors such as storage temperature and water activity, can be used to predict the accumulation of AFB<sub>1</sub> in spelt grains, which is a key step in risk assessment. By examining the influence of different levels contamination levels of spelt grain with AFB<sub>1</sub> and comparing to the control (uncontaminated) sample, the reduction in certain technological quality parameters and the potential loss of dough properties of spelt flour with AFB<sub>1</sub> content of 50 &mu;g/kg and 250 &mu;g/kg was pointed out.</p>
26

INVESTIGATION OF THE ROLE OF OXIDATIVE DNA DAMAGE IN AFLATOXIN B1-INDUCED PULMONARY CARCINOGENESIS

Guindon, Katherine 16 December 2008 (has links)
Studies described in this thesis were aimed at characterizing the mechanism(s) of aflatoxin B1 (AFB1) pulmonary carcinogenesis by addressing the formation, prevention, and repair of AFB1-induced oxidative DNA damage. The ability of AFB1 to cause oxidative DNA damage in different lung cell types of the A/J mouse was examined. The formation of 8-hydroxy-2’-deoxyguanosine (8-OHdG) in freshly isolated mouse lung alveolar macrophages, alveolar type II cells, and nonciliated bronchial epithelial (Clara) cells, was assessed by high performance liquid chromatography with electrochemical detection. An increase in 8-OHdG formation occurred in macrophage and Clara cell preparations isolated from A/J mice two hours following in vivo treatment with a single tumourigenic dose of AFB1. Prior treatment with polyethylene glycol-conjugated catalase (PEG-CAT) prevented the AFB1-induced increase in 8-OHdG levels in all mouse lung cell preparations. These results support the possibility that oxidative DNA damage in mouse lung cells contributes to AFB1 carcinogenicity. Mouse lung tumourigenesis was assessed following treatment of A/J mice with PEG-CAT and/or AFB1. Unexpectedly, the mean number of tumours per mouse and tumour size in the PEG-CAT + AFB1 group were greater than those of the group treated with AFB1 alone. There was no difference in K-ras exon 1 mutation spectrum or in the histological diagnosis of tumours between treatment groups. In vitro incubation with mouse liver catalase (CAT) resulted in conversion of [3H]AFB1 into a DNA-binding species, a possible explanation for the results observed in vivo. These results demonstrate that PEG-CAT is not protective against AFB1 carcinogenicity in mouse lung despite preventing DNA oxidation. The effect of in vivo treatment of mice with AFB1 on pulmonary and hepatic base excision repair (BER) activities and levels of 8-oxoguanine DNA glycosylase (OGG1) was investigated. AFB1 treatment increased 8-OHdG levels and BER activity in mouse lung, but did not significantly affect either in liver. Levels of OGG1 immunoreactive protein were increased in both mouse lung and liver. These results indicate that oxidative DNA damage may be an important mechanism in the carcinogenicity of AFB1. However, BER activity is increased by AFB1 treatment, possibly representing a compensatory response to the production of oxidative DNA damage. / Thesis (Ph.D, Pharmacology & Toxicology) -- Queen's University, 2008-12-12 10:00:44.81
27

ATOXIGENIC ASPERGILLUS FLAVUS ISOLATES AS CANDIDATE BIOCONTROL AGENTS IN MAIZE

MAURO, ANTONIO 23 February 2012 (has links)
Le aflatossine sono tra i composti naturali conosciuti più cancerogeni. Queste molecole, tossiche sia per gli animali sia per l’uomo, sono prodotte su importanti colture, quali mais, arachidi e cotone da differenti specie fungine di Aspergillus in particolare quelli afferenti alla sezione Flavi. In Italia il principale fungo responsabile della contaminazione da aflatossine su mais è A. flavus e l’area più esposta alla contaminazione è il nord della penisola dove si localizza circa il 90% della coltivazione del mais. Generalmente, le condizioni climatiche in questa area non sono favorevoli alla contaminazione da aflatossine; comunque stress idrico e alte temperature possono verificarsi durante il ciclo di crescita del mais favorendo la produzione di AFB1 da parte del fungo e determinando un accumulo superiore ai limiti di legge, come accadde nel 2003. Infatti, a partire dal 2003 più attenzione è stata dedicata alla caratterizzazione della popolazione italiana di A. flavus associate alla coltivazione del mais e allo sviluppo di una valida tecnica, come il controllo biologico degli isolati tossigeni mediante l’utilizzo di isolati non tossigeni, per ridurre la contaminazione da aflatossine. / Aflatoxins are the most carcinogenic natural compound known in nature. These molecules, toxic for animal and humans, are produced on important economic commodities worldwide by the secondary metabolism of several fungal species of Aspergilli of the section Flavi. In Italy the principal responsible of aflatoxins contamination on maize is A. flavus and the more exposed area to contamination is the northern of the peninsula where almost 90% of the cultivation is located. Generally, climatic conditions in this area are not favourable for aflatoxins contamination; however, reduced rainfall and increased temperature during maize developing season can occur along with associated levels of AFB1 exceeding the legal limits, as happened in 2003. Since this year, more attention has been dedicated to characterize Italian A. flavus populations associated with maize cultivation and to develop a useful tool to reduce aflatoxins contamination. To accomplish this goal, vegetative compatibility analysis, identification of atoxigenic isolates, evaluation of the ability of atoxigenic isolates to reduce in vitro aflatoxins produced by toxigenic isolates in vitro, selection of atoxigenic isolates potentially useful as biocontrol agents, individuate deletions in the aflatoxin biosynthesis gene cluster of selected atoxigenic isolates and biocontrol field trial with the selected potential biocontrol agents were achieved.
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Vliv plísní a jejich metabolitů na zdravotní stav zvěře / Influence of fungi and their metabolites on the health status of wildgame.

BOHÁČKOVÁ, Lenka January 2018 (has links)
The aim of this thesis was to evaluate the examined samples of liver tissue to find out the amount of aflatoxin in deer game. A total of 221 samples were examined for analysis purposes using the RIA method. Samples were obtained from dead and captured heads of deer game coming from private game reserves and game reserves belonging to the Forests of the Czech Republic. Samples of deer game were divided into groups according to their types, sex, and age. Sex was determined visually, and age via the development and grinding of the teeth. The highest concentration of B1 aflatoxin in liver was measured in a 6 year-old dead female (7,39 g.kg-1). According to the statistical evaluation (P <0,05), a significant difference was proven between dead and captured heads, between males and females, and even between age groups. There is a higher aflatoxin B1 concentration in dead heads´ liver, approximately in 2,12 g.kg-1 higher than in captured heads. Females´ liver proved to contain a higher concentration of B1 aflatoxin, approximately in 0,63 g.kg-1 higher than in males. Age groups have proven that the older the animals, the higher the B1 aflatoxin concentration in their liver.
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Efeitos da administração da aflatoxina, fumonisina e curcumina, isoladas ou associadas, sobre a resposta imunológica humoral e determinação de produtos de biotransformação em frangos de corte / Effects of aflatoxin, fumonisin and curcumin, alone or in combination, on the humoral immune response and determination of biotransformation products in broiler chickens

Diane Valgañon de Neeff 12 September 2016 (has links)
O objetivo da pesquisa foi avaliar os efeitos da AFB1 e FB1, isoladas e associadas e com ou sem a inclusão de um antioxidante (cúrcuma) em frangos de corte, utilizando-se os seguintes tratamentos (T): T1 (controle): 0 AFB1 + 0 FB1 + 0 Cúrcuma; T2: 0 AFB1 + 0 FB1 + 222 mg/kg Cúrcuma; T3: 0 AFB1 + 20 mg/kg FB1 + 0 Cúrcuma; T4: 0 AFB1 + 20 mg/kg FB1 + 222 mg/kg Cúrcuma; T5: 0,5 mg/kg AFB1 + 0 FB1 + 0 Cúrcuma; T6: 0,5 mg/kg AFB1 + 0 FB1 + 222 mg/kg Cúrcuma; T7: 0,5 mg/kg AFB1 + 20 mg/kg FB1 + 0 Cúrcuma; T8: 0,5 mg/kg AFB1 + 20 mg/kg FB1 + 222 mg/kg Cúrcuma. Os parâmetros avaliados incluíram: conversão alimentar, ganho de peso, consumo alimentar, proteínas séricas, hematologia, enzimas hepáticas, histopatologia de vísceras, resposta vacinal, resíduos de aflatoxinas e fumonisina em vísceras e músculos. Os dados foram analisados como um fatorial 2 x 2 x 2 por análise de variância. Não houve interação significativa para os três fatores analisados no desempenho zootécnico, porém houve diferença significativa nas dietas contendo aflatoxina, quando comparada com as outras dietas, para todas as variáveis analisadas. A AST e LDH foram as únicas variáveis significativas para a interação de todos os fatores (AFB1, FB1 e CMT), porém as outras variáveis, exceto a GGT, apresentaram diferença significativa nas dietas contendo aflatoxina, quando comparada com as outras dietas, para todas as variáveis analisadas. As lesões histopatológicas no fígado, rim e bursa de Fabricius foram aumentando gradualmente do tratamento controle até o tratamento contendo adição de aflatoxina e fumonisina, com ou sem cúrcuma, sendo que o efeito mais severo foi observado nos órgãos desses tratamentos. Não houve diferença significativa com a inclusão da cúrcuma. Não houve nenhuma variável significativa para a interação de todos os fatores avaliados para a biometria dos órgãos, porém fígado, rim e coração apresentaram diferença significativa nas dietas contendo aflatoxina, quando comparada com as outras dietas, para todas as variáveis analisadas. Nenhuma variável foi significativa para a interação de todos os fatores avaliados para o hemograma aos 21 dias, porém aos 42 dias, leucócitos, linfócitos e basófilos apresentaram diferença significativa para a interação de todos os fatores. Não houve diferença estatística para a interação dos três fatores analisados para os títulos de anticorpos para a doença de Newcastle. Os resíduos de FB2 no fígado e AFB2 no músculo peitoral foram as únicas variáveis significativas para a interação de todos os fatores analisados. Os resultados obtidos indicam que não houve efeito da cúrcuma na diminuição dos efeitos deletérios da aflatoxina e fumonisina. / The objective of this research project was to evaluate the effects of AFB1 and FB1, alone or in combination and associated or not with an antioxidant (turmeric) in broiler chickens, using the following treatments (T): T1 (control): 0 AFB1 + 0 FB1 + 0 Turmeric; T2: 0 AFB1 + 0 FB1 + 222 mg/kg Turmeric; T3: 0 AFB1 + 20 mg/kg FB1 + 0 Turmeric; T4: 0 AFB1 + 20 mg/kg FB1 + 222 mg/kg Turmeric; T5: 0.5 mg/kg AFB1 + 0 FB1 + 0 Turmeric; T6: 0.5 mg/kg AFB1 + 0 FB1 + 222 mg/kg Turmeric; T7: 0.5 mg/kg AFB1 + 20 mg/kg FB1 + 0 Turmeric; T8: 0.5 mg/kg AFB1 + 20 mg/kg FB1 + 222 mg/kg Turmeric. The parameters evaluated included: feed conversion, weight gain, food intake, serum proteins, hematology, liver enzymes, histopathology of viscera, vaccine response and residues of aflatoxin and fumonisin in tissues of viscera and muscles. Data were analyzed as a 2 x 2 x 2 factorial by analysis of variance. There was no significant interaction for the three analyzed factors on the performance, but there were significant differences in the diets containing aflatoxin when compared to the other diets, for all variables analyzed. AST and LDH were the only significant variables for the interaction of all factors (AFB1, FB1 e CMT), but other variables, with the exception of GGT, showed significant difference in diets containing aflatoxin when compared to other diets for all the variables analyzed. Histopathological lesions in the liver, kidney and bursa of Fabricius were gradually increased from the control treatment to aflatoxin and fumonisin treatment, with or without turmeric, with the most severe effect being observed in the organs of these treatments. There was no significant variable for the interaction of all factors evaluated for organ biometry, but liver, kidney and heart showed a significant difference in diets containing aflatoxin when compared to other diets for all variables analyzed. No variable was significant for the interaction of all factors evaluated for the blood test at 21 days, but at 42 days leukocytes, lymphocytes and basophils showed significant differences for the interaction of all factors. There was no statistical difference for the interaction of all factors analyzed for antibody titers to Newcastle disease. The residues of FB2 in the liver and AFB2 in the pectoral muscle were significant for the interaction of all the factors. The results showed no effect of turmeric powder in reducing the deleterious effects of aflatoxin and fumonisin.
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Determinação de biomarcadores de aflatoxina B1 e aplicabilidade na avaliação da eficiência de adsorventes em frangos de corte / Determination of Aflatoxin B1 biomarkers and its aplicability on efficience avaliation of adsorbents in broiler chickens

Agatha Cristina de Pinho Carão 29 February 2016 (has links)
As aflatoxinas são metabólitos secundários produzidos por fungos toxigênicos das espécies Aspergillus flavus, A. parasiticus e A. nomius. São amplamente encontradas em matérias-primas de rações animais, em especial o milho, e têm a capacidade de levar a quadros clínicos agudos ou crônicos de aflatoxicose, caracterizados por, desde a morte por hepatite aguda até a diminuição do desempenho zootécnico por diminuição de peso ou consumo de ração. A aflatoxina B1 tem sido considerada o metabólito mais perigoso, uma vez que possui alto poder hepatotóxico, além de ser mutagênica e carcinogênica. Atualmente a ciência trabalha rumo à descoberta de substâncias que sejam indicadoras confiáveis de contaminação por componentes tóxicos em homens e em animais, os chamados biomarcadores, que medem uma mudança celular, biológica ou molecular em um meio biológico (tecidos humanos, células ou fluídos) que fornecem informação a respeito de uma doença ou exposição a uma determinada substância. Sua detecção pode auxiliar na identificação, no diagnóstico e no tratamento de indivíduos afetados que podem estar sob risco, mas ainda não exibem os sintomas. Sendo assim, com o auxílio de análises que confirmem a patogenicidade da aflatoxina B1 (determinação da atividade de enzimas hepáticas, da avaliação da função renal, de hematologia, da dosagem de minerais séricos e da avaliação de desempenho zootécnico), o objetivo deste trabalho foi avaliar a aplicabilidade da determinação de resíduos hepáticos de aflatoxinas e do aduto sérico AFB1-lisina na avaliação da eficiência de adsorventes em frangos de corte. Utilizou-se 240 pintos de 1 dia, machos, de linhagem Cobb 500&reg;, distribuídos aleatoriamente em 4 dietas experimentais: Controle Negativo: Ração Basal (RB); RB &#43; 0,5% de adsorvente ((aluminosilicato de cálcio e sódio hidratado/HSCAS); RB &#43; 0,5% de adsorvente &#43; 500 &micro;g de AFB1/kg de ração e; RB &#43; 500 &micro;g de AFB1/kg de ração.Os resultados experimentais mostram que o efeito deletério da AFB1, na concentração utilizada, é mais pronunciado que os efeitos protetores do HSCAS sobre os parâmetros de saúde dos animais. Não houve ação efetiva do adsorvente utilizado sobre quase nenhuma variável estudada, apenas para a redução das lesões histopatológicas em fígado, na redução da concentração de gama-glutamiltransferase (GGT), fósforo e aumento da contagem de hemáceas aos 21 dias de idade. Porém, influenciou positivamente a redução de resíduos hepáticos de aflatoxina G1 aos 21 dias e as concentrações de AFB1-lisina sérica aos 21 e aos 42 dias de idade. Estes dados são importantes porque permite concluir que, embora sintomatologicamente o HSCAS não tenha exercido função efetiva, molecularmente foi capaz de mostrar de eficácia sobre os alguns biomarcadores de aflatoxinas no organismo das aves / Aflatoxins are secondary metabolites produced by toxigenic fungi of the species Aspergillus flavus, A. parasiticus and A. nomius. They are widely found in raw materials of animal feed, in particular corn, and have the ability to lead to clinical cases of acute or chronic aflatoxicosis, characterized by acute hepatites leading to death until lower performance by decreased weight or feed intake. Aflatoxin B1 has been considered the most dangerous metabolite, since it has high hepatotoxic power, besides being mutagenic and carcinogenic. Nowadays science works toward the discovery of substances that are reliable indicators of contamination by toxic components in humans and animals, called biomarkers, which measure a cell change, biological or molecular in a biological medium (human tissues, cells or fluids) that provide information regarding a disease or exposure to a particular substance. Its detection can assist in the identification, diagnosis and treatment of affected individuals who may be at risk, but still do not exhibit symptoms. Thus, with the help of analysis that confirm aflatoxin B1 pathogenicity (determination of liver enzymes activity, assessment of renal function, hematology, dosage of serum minerals and evaluation of animal performance), the objective of this work was to evaluate the applicability of the determination of aflatoxin liver residues and serum AFB1-lysine adduct in the evaluation of the adsorbents efficiency in broiler chickens. Two hundred and fourty day-old male chicks, Cobb 500&reg; lineage, were randomly distributed into 4 experimental diets: Negative Control: Basal Feed (BF); BF &#43; 0.5% adsorbent (hydrated sodium calcium aluminosilicate/HSCAS); RB &#43; 0.5% adsorbent &#43; 500 &micro;g AFB1/kg of feed; and RB &#43;500 &micro;g AFB1/kg of feed. The experimental results show that the deleterious effect of AFB1, at the concentration used, is more pronounced that the protective effects of HSCAS on animal health parameters. There was no effective action of the adsorbent used on almost any variable studied, only for the reduction of the histopathological lesions in the liver, reduction of gamma-glutamyltransferase (GGT) and phosphorus concentration, and increased count of red blood cells at 21 days. However, influenced positively the reduction of aflatoxin G1 liver residues at 21 days and the concentrations of serum AFB1-lysine at 21 and 42 days. These are important data because they allow to conclude that, although symptomatically the HSCAS has not exercised effective function, molecularly was able to show some efficacy on aflatoxin biomarkers in the birds body

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