RT-QuIC detection of chronic wasting disease prion in platelet samples of white-tailed deer.

BACKGROUND: Chronic wasting disease (CWD) is a prion disease of captive and free-ranging cervids. Currently, a definitive diagnosis of CWD relies on immunohistochemistry detection of PrPSc in the obex and retropharyngeal lymph node (RPLN) of the affected cervids. For high-throughput screening of CWD in wild cervids, RPLN samples are tested by ELISA followed by IHC confirmation of positive results. Recently, real-time quacking-induced conversion (RT-QuIC) has been used to detect CWD positivity in various types of samples. To develop a blood RT-QuIC assay suitable for CWD diagnosis, this study evaluated the assay sensitivity and specificity with and without ASR1-based preanalytical enrichment and NaI as the main ionic component in assay buffer. RESULTS: A total of 23 platelet samples derived from CWD-positive deer (ELISA + /IHC +) and 30 platelet samples from CWD-negative (ELISA-) deer were tested. The diagnostic sensitivity was 43.48% (NaCl), 65.22% (NaI), 60.87% (NaCl-ASR1) or 82.61% (NaI-ASR1). The diagnostic specificity was 96.67% (NaCl), 100% (NaI), 100% (NaCl-ASR1), or 96.67% (NaI-ASR1). The probability of detecting CWD prion in platelet samples derived from CWD-positive deer was 0.924 (95% CRI: 0.714, 0.989) under NaI-ASR1 experimental condition and 0.530 (95% CRI: 0.156, 0.890) under NaCl alone condition. The rate of amyloid formation (RFA) was greatest under the NaI-ASR1 condition at 10-2 (0.01491, 95% CRI: 0.00675, 0.03384) and 10-3 (0.00629, 95% CRI: 0.00283, 0.01410) sample dilution levels. CONCLUSIONS: Incorporation of ASR1-based preanalytical enrichment and NaI as the main ionic component significantly improved the sensitivity of CWD RT-QuIC on deer platelet samples. Blood test by the improved RT-QuIC assay may be used for antemortem and postmortem diagnosis of CWD.

A microfluidic biosensor for the diagnosis of chronic wasting disease.

Cervids are affected by a neurologic disease that is always fatal to individuals and has population effects. This disease is called chronic wasting disease (CWD) and is caused by a misfolded prion protein. The disease is transmitted via contact with contaminated body fluids and tissue or exposure to the environment, such as drinking water or food. Current CWD diagnosis depends on ELISA screening of cervid lymph nodes and subsequent immunohistochemistry (IHC) confirmation of ELISA-positive results. The disease has proven to be difficult to control in part because of sensitivity and specificity issues with the current test regimen. We have investigated an accurate, rapid, and low-cost microfluidic microelectromechanical system (MEMS) biosensing device for the detection of CWD pathologic prions in retropharyngeal lymph nodes (RLNs), which is the current standard type of CWD diagnostic sample. The device consists of three novel regions for concentrating, trapping, and detecting the prion. The detection region includes an array of electrodes coated with a monoclonal antibody against pathologic prions. The experimental conditions were optimized using an engineered prion control antigen. Testing could be completed in less than 1 hour with high sensitivity and selectivity. The biosensor detected the engineered prion antigen at a 1:24 dilution, while ELISA detected the same antigen at a 1:8 dilution. The relative limit of detection (rLOD) of the biosensor was a 1:1000 dilution of a known strong positive RLN sample, whereas ELISA showed a rLOD of 1:100 dilution. Thus, the biosensor was 10 times more sensitive than ELISA, which is the currently approved CWD diagnostic test. The biosensor's specificity and selectivity were confirmed using known negative RPLN samples, a negative control antibody (monoclonal antibody against bovine coronavirus BCV), and two negative control antigens (bluetongue virus and Epizootic hemorrhagic disease virus). The biosensor's ability to detect pathogenic prions was verified by testing proteinase-digested positive RLN samples.

Aflatoxins and fumonisins in feed from a broiler operation system from São Paulo state, Brazil / Aflatoxinas e fumonisinas em rações de um sistema de produção de frangos de corte no estado de São Paulo, Brasil

ABSTRACT: The aim of the present study was to assess the occurrence of aflatoxins (AFs) and fumonisins (FBs) in feed ingredients (corn and soybean meal) and finishing feed in a broiler operation system, as well was to evaluate their effect on the productivity of 20 batches of broilers produced and the histology status of broilers' liver after slaughter. Corn samples presented the highest frequencies of AFs and FBs, at mean levels of 29.1 and 2,100µg/kg, respectively. Soybean samples presented mean levels of 1.5 and 70µg/kg for AFs and FBs, respectively. Batches of broilers receiving feed containing FB levels higher than 1,000µg/kg had lower weight gain and higher mortality rates, while those fed rations with AFs equal or above the limit of quantification (LOQ) of the analytical method presented higher scores of histological changes in the liver. A dilution effect was observed for AFs and FBs from ingredients, especially corn, to feed during manufacture, whilst not enough to prevent losses in productivity. Results of this trial highlighted the need for strict control of mycotoxins in corn intended for broilers.

RESUMO: O objetivo do presente trabalho foi verificar a ocorrência de aflatoxinas (AFs) e fumonisinas (FBs) em ingredientes (milho e farelo de soja) e na ração de abate sobre a produtividade de uma empresa integradora de frangos de corte, bem como avaliar seus efeitos sobre produtividade de 20 lotes de frangos produzidos pela empresa e a histologia dos fígados dos frangos após o abate. As amostras de milho apresentaram as maiores frequências de AFs e FBs, em concentrações médias de 29,1 e 2.100µg/kg, respectivamente. As amostras de farelo de soja apresentaram níveis médios de 1,5 e 70µg/kg para AFs e FBs, respectivamente. Os lotes de aves que receberam ração contendo níveis de FBs maiores que 1,000µg/kg apresentaram menor ganho de peso e maior percentual de mortalidade, enquanto que as que receberam ração com AFs iguais ou superiores ao limite de quantificação (LQ) do método analítico apresentaram maior grau de alteração histopatológica no fígado. Houve efeito de diluição de AFs e FBs dos ingredientes, especialmente o milho, à ração no processo de fabricação, porém não suficiente para evitar perdas na produtividade. Os resultados do estudo reforçam a necessidade do controle estrito de micotoxinas no milho destinado à alimentação de frangos de corte.

Avaliação do desempenho de frangos de corte alimentados com rações contendo probiótico e diferentes níveis de nucleotídeos / Performance evaluation of broilers fed diets containing probiotic and different nucleotides levels

objetivo deste trabalho foi avaliar o desempenho de frangos de corte alimentados com ração contendo um probiótico comercial e diferentes níveis de nucleotídeos. Foram utilizados 1050 pintos de 01 dia, machos da linhagem Ross 308 totalizando trinta e cinco aves por boxe, em um delineamento inteiramente casualizado com cinco repetições por tratamento. As aves foram criadas até 42 dias de idade, e receberam as rações experimentais a base de milho e farelo de soja contendo 6 níveis de nucleotídeos (0; 100; 200; 300; 400 e 500 gramas por tonelada de ração). Os nucleotídeos foram utilizados na fase inicial (1 a 21 dias) e fase de crescimento (22 a 35 dias). Durante a fase final (36 a 42 dias) os nucleotídeos foram removidos da ração . Houve melhora linear no desempenho dos frangos no período de 1 a 21 dias, indicando que, quanto maior o nível de nucleotídeos na dieta, maior o peso corporal das aves. A conversão alimentar também melhorou linearmente nesse período à medida que aumentou o nível de nucleotídeos na ração. O peso no período de 35 dias, também teve um comportamento linear, semelhante ao período de 1 a 21 dias, indicando que, o nível de nucleotídeos na ração melhorou o desempenho. A concentração plasmática de acido úrico demonstrou efeito quadrático no período de 1 a 21 dias, indicando 231,59 gramas de nucleotídeos por tonelada de ração, como o melhor, em níveis mínimos de ácido úrico, por outro lado, no período de 35 dias de idade, estimou-se o nível de 208,99 g de nucleotídeos por tonelada de ração; como o melhor em níveis mínimos de ácido úrico no sangue. No período final (35 a 42 dias) e período total (1 a 42 dias de idade) não foi possível o observar efeito dos contrastes testados neste trabalho.

The objective of this study was to evaluate the performance of broilers fed diets containing a commercial probiotic and different levels of nucleotides. One thousand and fifty chicks 1-d male were reared in a randomized experimental design with five replications of each treatment, distributed in 30 experimental boxes with 35 birds each. The diets contained corn and soybean meal with six different nucleotídes levels (0; 100; 200; 300; 400 and 500 grams for ton of ration), and the different nucleotides levels were used in the initial phase (1 to 21 days of age) and growth phase (22 to 35 days of age). During the final phase (36 to 42 days) nucleotides were removed from the feed. There was improvement on broilers performance in the period from 1 to 21 days of age, demonstrating proportionality between nucleotides level in the diet of broilers and body weight of the birds. Feed conversion at 21 days of age was directly proportional to nucleotides level in the diet. Body weight at 35 days of age, also had a linear behavior, similar to the period from 1 to 21 days, indicating that the nucleotides level in the feed improved the performance. Plasma uric acid concentration demonstrated quadratic effect at 21 days of age, showing that 231,59 grams of nucleotides for ton of feed had the minimum level of plasma uric acid concentration. At 35 days of age, concentration of 208,99 g of nucleotides for ton of feed had the minimum level of plasma uric acid concentration. No effects were observed in the final period (35 to 42 days of age) and total period (1 to 42 days of age) it was not demonstrated effect of the contrasts tested in this study.

Suplementação de acidificantes em rações de leitõesdesmamados: desempenho e digestibilidade / Supplementation of acidifiers in diets of weaned pigs: performance and digestibility

Em dois ensaios experimentais avaliou-se efeito dietético da suplementação de acidificantes sobre o desempenho (ensaio1) e coeficientes de digestibilidade aparente de nutrientes (ensaio 2) em suínos. No ensaio 1, com duração de 42 dias,120 leitões desmamados aos 21 dias foram distribuídos em oit8 blocos experimentais com três leitões por baia, foramaplicados cinco tratamentos, sendo um controle e4quatro com a inclusão de acidificantes. No ensaio 2,0dez leitões compeso médio inicial de 16,4 kg foram distribuídos em dois blocos experimentais, cada um com cinco repetições, sob doistratamentos (ração sem acidificante ou com 1,0% de ácido fumárico). No estudo de desempenho, a adição de ácidofumárico nas rações determinou aumentos no consumo de ração nos períodos de 0 aos 15 dias, 0 aos 32 dias e ganhode peso de 0 aos 42 dias, quando comparado ao tratamento controle. No ensaio 2, a adição de 1,0% de ácido fumáricona ração não alterou os coeficientes de digestibilidade aparente da matéria seca e demais componentes químicos dasdietas. A ausência de diferenças nos coeficientes de digestibilidade aparente dos nutrientes dietéticos com a inclusão doacidificante provavelment, deveu-se ao curto período de avaliação. A inclusão de ácido fumárico nas rações de leitõesdesmamados favoreceu o desempenho dos leitões.

In two experimental assays it was evaluated the diet acidifier supplementation effect on performance (assay 1) and onnutrient apparent digestibility coefficients (assay 2). During 42 days in assay 1, 120 piglets weaned at 21-days years oldwere allotted in8eight experimental block design with3three pigs per experimental unit. The treatments were a controland4four acidified diets. In assay 2,0ten piglets with an average weight of 16,4 kg were allotted in two experimentalblock design receiving two treatments under five replications (control diet without acidifier or supplied with 1,0%fumaric acid). On performance study the fumaric acid inclusion in the diet permitted a feed intake increase from 0 to15 days, and weight gain from 0 to 32 days and from 0 to 42 days. In assay 2, the diet 1,0% of fumaric acid inclusion didnot modified the apparent digestibility coefficients of dry matter and moreover diet chemical compounds. The similarapparent digestibility coefficient of dietetic nutrients with the acidifier inclusio, probabl, occurred due to the shortperiod of evaluation. The fumaric acid inclusion in weaned piglet diets improved performance of piglets.

Effects of aflatoxin B(1) and fumonisin B(1) on blood biochemical parameters in broilers.

The individual and combined effects of dietary aflatoxin B(1 )(AFB(1)) and fumonisin B(1) (FB(1)) on liver pathology, serum levels of aspartate amino-transferase (AST) and plasma total protein (TP) of broilers were evaluated from 8 to 41 days of age. Dietary treatments included a 3 × 3 factorial arrangement with three levels of AFB(1 )(0, 50 and 200 µg AFB(1)/kg), and three levels of FB(1 )(0, 50 and 200 mg FB(1)/kg). At 33 days post feeding, with the exception of birds fed 50 mg FB(1 )only, concentrations of AST were higher (p < 0.05) in all other treatment groups when compared with controls. Plasma TP was lower (p < 0.05) at six days post feeding in groups fed 200 µg AFB(1)/kg alone or in combination with FB(1). At day 33 days post feeding, with the exception of birds fed the highest combination of AFB(1 )and FB(1 )which had higher plasma TP than control birds(, )plasma TP of birds fed other dietary treatments were similar to controls. Broilers receiving the highest levels of AFB(1) and FB(1) had bile duct proliferation and trabecular disorder in liver samples. AFB(1) singly or in combination with FB at the levels studied, caused liver damage and an increase in serum levels of AST.

Mycoflora and co-occurrence of fumonisins and aflatoxins in freshly harvested corn in different regions of Brazil.

Natural mycoflora and co-occurrence of fumonisins (FB(1), FB(2)) and aflatoxins (AFB(1), AFB(2), AFG(1) and AFG(2)) in freshly harvested corn grain samples from four regions of Brazil were investigated. Fusarium verticillioides was predominant in all samples. Analysis of fumonisins showed that 98% of the samples were contaminated with FB(1) and 74.5% with FB(1) + FB(2), with toxin levels ranging from 0.015 to 9.67 microg/g for FB(1) and from 0.015 to 3.16 microg/g for FB(2). Twenty-one (10.5%) samples were contaminated with AFB(1), seven (3.5%) with AFB(2) and only one (0.5%) with AFG(1) and AFG(2) Co-contamination with aflatoxins and fumonisins was observed in 7% of the samples. The highest contamination of fumonisins and aflatoxins was observed in Nova Odessa (SP) and Várzea Grande (MT), respectively. The lowest contamination of these mycotoxins was found in Várzea Grande and Nova Odessa, respectively.

Efeitos de diferentes relações dietéticas de energia metabolizável: proteína bruta e do peso inicial de pintos sobre o desempenho e o rendimento de carcaça em frangos de corte fêmeas / Effect of differents dietary relationship metabolizable energy: crude protein and the initial weight of chicks on the performance and yield of carcass in females broilers

O estudo foi realizado para verificar o efeito de diferentes relações dietéticas de energia metabolizável: proteína bruta e do peso inicial de pintos de corte de 01 sobre o desempenho e rendimento de carcaça em frangos de corte. Foram utilizados 640 pintos, fêmeas, de uma linhagem comercial para corte (Cobb). O delineamento experimental utilizado foi de blocos ao acaso, em esquema fatorial 2 x 2, sendo empregados dois níveis de peso de pintos de 01 dia (38g e 46g) e dois níveis de relação EM:PB (Alto – 149,8; 174,4 e; 194,4 e, Baixo – 130,0;150,0 e; 166,7, para ração inicial, crescimento e final, respectivamente) totalizando, assim, 4 tratamentos, cada um com 4 repetições de 40 aves, criados até 48 dias de idade. Foram avaliados o Consumo de Ração (CR), Ganho de Peso (GP), Conversão Alimentar (CA) durante o período experimental e, Rendimento de Carcaça e Rendimento de Cortes (Asa, coxa+sobrecoxa, peito, cabeça, pé e dorso) no final doperíodo experimental. Nas variáveis CR e GP não foram observados efeitos significativos (P>0,05) em nenhum dos tratamentos e períodos. Na variável CA, observou-se efeito significativo (P<0,05)no período de 1 a 35 dias de idade onde as aves alimentadas com adieta com Relação EM:PB baixa apresentaram uma pior conversão alimentar, independente do peso inicial. No rendimento de carcaça houve efeito significativo (P<0,05), onde as aves com maior peso inicial obtiveram uma melhor porcentagem de rendimento quando receberam, durante todo o período de criação, dietas com relação EM:PB alta

This study was accomplished to verify the effect of the differents dietary relationship metabolizable energy: crude protein and the initial weight of chicks on the performance and yield of carcass in broilers. There were used 640 female chickens of the commercial ancestry (Cobb). A completely randomized trial was applied, in factorial outline 2x2, with two levels of chicks’ weight (38g and 46g) and two levels of relationship ME:CP(High - 149,8; 174,4 e; 194,4 and, Low - 130,0; 150,0 e; 166,7, for the initial, growth and end ration, respectively), totalizing 4 treatments, each one of them with 4 repetitions of 40 chicks, ranging until 48 days ofage. There were evaluated the Feed Intake (FI), Weight Gain (WG), Feed Conversion (FC) and Mortality, during all the experimental period and, performance and chemical composition of carcass in the end of the experimental period. There was no significant difference (P>0,05) in feed intake and weight gain in the tested treatments. However, there was significant difference (P<0,05) at the FC, when the broilers were fed with Low Relationship ME:CP ration and showed the worst result, independent of the initial weight, during the 1 to 35 days of age. In the composition of carcass there was significant effect (P<0,05), where the high initial weight broilers fed with High Relationship ME:CP ration showed better results