RESUMO: Para avaliar o sucesso de um protocolo de desmame precoce segregado medicado para a eliminação de Actinobacillus pleuropneumoniae, dez lotes consecutivos de 100 suínos por lote desmamados aos 7-9 dias de idade foram monitorados às 21-22 semanas de idade procurando a presença de tosse produtiva, presença de anticorpos contra o agente e lesões pulmonares compatíveis com pleuropneumonia no abate. Além disso, as tonsilas inteiras foram processadas para a identificação de A. pleuropneumoniae por isolamento bacteriológico e nested PCR usando um método direto. Os resultados serológicos (1,4%) e PCR (3,5%) positivos sugerem que não foi possível erradicar em todos os lotes, mesmo usando um protocolo de desmame precoce segregado medicado.

ABSTRACT: To assess the success of a segregated medicated early weaning protocol for elimination of Actinobacillus pleuropneumoniae, ten consecutive batches of 100 pigs per batch weaned at 7-9 days of age were monitored at 21-22 weeks of age looking for presence of productive cough, presence of antibodies against the agent and pleuropneumonia-compatible lung lesions at slaughter. Also, whole tonsils were processed for A. pleuropneumoniae identification by both bacteriological isolation and nested-PCR using a direct method. Positive serological test (1.4%) and PCR (3.5%) results, suggested that A. pleuropneumoniae could not be eradicated in all batches, even using segregated medicated early weaning protocol.

The objective of the study was to determine Mycoplasma hyopneumoniae infection and the presence of swine enzootic pneumonia (SEP) in pigs of herds from Mendoza province. In each of five herds, 18 to 20-week-old pigs were observed looking for non-productive cough and 20 of these pigs were sampled for PCR (nasal swab). The pigs were slaughtered at abattoir, where their lungs were inspected looking for SEP-compatible macroscopic lesions. Prevalence of lung lesions, percentage of affected area, and pneumonia index were calculated. In addition, 20 lung samples were collected for histopathology and bronchoalveolar lavage (BAL) for PCR. The presence of the agent in BAL samples (20% - 90%) was observed in all herds, as well as a high percentage of macroscopic (57% - 97%) and microscopic (10% - 40%) lung SEP-compatible lesions and non-productive cough (6% - 25%). The results obtained in the present study would indicate that more than half of 50- 500 sow herds in Mendoza province are infected with M. hyopneumoniae and that the impact of the NEP is important in these herds.

El objetivo del trabajo fue determinar la infección por Mycoplasma hyopneumoniae y la presencia de neumonía enzoótica porcina (NEP) en cerdos de granjas porcinas de la provincia de Mendoza. En cada una de cinco granjas, cerdos de 18-20 semanas de edad fueron observados en busca de tos no productiva y 20 de ellos muestreados para PCR (hisopado nasal). Los cerdos fueron faenados en frigorífico, donde se inspeccionaron sus pulmones en busca de lesiones macroscópicas compatibles con NEP y se calculó la prevalencia de lesiones, el área pulmonar afectada y el índice de neumonía. Además se tomó de 20 animales muestra de lesión para histopatología y de lavado broncoalveolar (LBA) para PCR. Se observó la presencia del agente en muestras de LBA (20% - 90%) en todas las granjas, así como también un alto porcentaje de lesiones pulmonares macroscópicas (57% - 97%) y microscópicas (10% - 40%) compatibles con NEP y tos no productiva (6% - 25%). Los resultados obtenidos indicarían que más de la mitad de las piaras de entre 50 y 500 madres de la provincia de Mendoza están infectadas con M. hyopneumoniae y que el impacto de la NEP es importante en estas piaras.

It is important to identify distinct Mycoplasma hyopneumoniae genotypes to improve the study and understanding of some epidemiological aspects of the disease it produces. MLVA (Multiple-Locus Variable-number tandem-repeats Analysis) methodology would be the most adequate for typing this pathogen from clinical samples. The objective of the present study was to design nested PCR assays for VNTR (Variable Number of Tandem Repeats) loci P97, H4, and H5 with the aim to obtain a high analytical sensitivity. To evaluate them, DNA samples positive for M. hyopneumoniae were analyzed by the nested PCR assays in parallel to conventional PCR assays, and the proportion of positive results with each approach were compared. Taking into account the higher sensitivity of the PCR assays developed in this study, it was concluded that the recommended approach to type M. hyopneumoniae from clinical samples - even when they contain a low load of the agent- is to perform nested PCR assays for these loci, along with the other one previously informed for P146.

Identificar distintos genotipos de Mycoplasma hyopneumoniae es importante para estudiar y entender mejor algunos aspectos epidemiológicos de la enfermedad que éste produce. La metodología de MLVA (Multiple-Locus Variable-number tandem-repeats Analysis) sería la más adecuada para la tipificación del patógeno a partir de muestras clínicas. El objetivo del presente trabajo fue diseñar PCR anidadas para los loci VNTR (Variable Number of Tandem Repeats) P97, H4 y H5 con la finalidad de obtener pruebas de mayor sensibilidad analítica. Para evaluarlas se analizaron muestras de ADN positivas para M. hyopneumoniae en paralelo con una PCR convencional para cada locus y se compararon las proporciones de positivos con cada formato. Dada la mayor sensibilidad de las reacciones desarrolladas en el presente estudio, se recomienda utilizar reacciones anidadas de estos loci para la tipificación de M. hyopneumoniae en muestras clínicas, y realizarlas en conjunto con la PCR anidada para el locus P146 previamente informada

Mycoplasma bovis is the most important cause of mycoplasmal mastitis in dairy cows and has been diagnosed in our country and worldwide. MLVA analysis seems to be a suitable tool to type this pathogen, for epidemiological studies of outbreaks. In the present work, 7 strains of M. bovis were analyzed. They had been obtained from 2 different herds (milk samples from bulk tank milk and mammary quarters of cows with and without mastitis´s clinical signs) and had been previously identified. Four tandem repeat regions (TR) were studied. Among the TR loci studied, variability was found in only one of them (TR52), in which 2 possible alleles were observed in samples from cows with clinical mastitis. According to the author´s knowledge this is the first report of the use of MLVA for the genetic subtyping of M. bovis strains in Argentina.

Mycoplasma bovis es el mycoplasma causante de mastitis más importante en vacas lecheras y ha sido diagnosticado en nuestro país así como a nivel mundial. Para realizar estudios epidemiológicos de brotes, el análisis por MLVA parece ser una herramienta adecuada para la tipificación genética del patógeno. En el presente trabajo se analizaron 7 cepas de M. bovis provenientes de 2 tambos distintos (muestras de leche de tanque de enfriado, y cuartos mamarios de vacas con y sin signos de mastitis) que habían sido previamente identificadas. Se estudiaron por PCR 4 regiones que comprenden secuencias repetidas en tándem (TR). Dentro de los loci TR analizados, sólo se encontró variabilidad en TR 52, en el cual se observaron 2 posibles alelos en muestras que provenían de vacas con mastitis clínica. Según el conocimiento de los autores es la primera vez que se informa la utilización del análisis MLVA para detectar subtipos genéticos entre cepas de M. bovis en Argentina

The diagnosis of tuberculosis in live animals is carried out using primarily by the tuberculin test (TT), however only few reports only show the results of this diagnostic test in swine. The objective of this study was to compare the TT with pathological and microbiological findings in swine. A total of 307 sows were injected with avium PPD and bovine PPD following the standard technique. Tissues samples for bacteriological tests and histological exams were collected from 171 animals after slaughter. The following results were obtained: 14.4% (44) tested positive to avium PPD, 1.9% (6) to bovine PPD, 3.9% (12) to both PPD and 79.8% (245) were negatives. Only 4 samples were culture positives typified by Mycobacterium bovis, M. avium, M. fl avescens y M. scrofulaceum. Neither macroscopic nor histological examinations revealed lesions compatible with TB.

El diagnóstico de tuberculosis en animales vivos se realiza casi exclusivamente mediante la prueba intradérmica tuberculínica (IDR), aunque en los porcinos son escasos los reportes de resultados utilizando dicha técnica. El objetivo de este trabajo fue comparar resultados obtenidos realizando la IDR en porcinos con hallazgos patológicos y microbiológicos. Se tuberculinizaron 307 hembras con DPP aviar y DPP bovino. Del total, 171 se inspeccionaron a la faena tomando muestras para exámenes bacteriológicos e histopatológicos. Los resultados de la IDR fueron: 14.4% (44) positivos a DPP aviar, 1.9% (6) a DPP bovino, 3.9% (12) a ambos DPP y 79.8% (245) negativos. Cuatro muestras fueron positivas al cultivo, tipificándose como Mycobacterium bovis, M. avium, M. flavescens y M. scrofulaceum. En la observación macroscópica e histopatológica no se hallaron lesiones compatibles. Concluimos que la IDR sería útil para indicar una infección predial aunque tendría limitaciones en el diagnóstico individual y en el estudio comparativo con la presencia de lesiones y aislamiento del agente.

Determinou-se, por meio de um sistema de monitoramento de suínos em fase de crescimento e em matadouro, a presença de patologias como indicadoras de problemas na população de referência. O estudo foi realizado em uma criação intensiva de ciclo completo, durante nove semanas. Foram determinadas as prevalências dos diagnósticos clínico-patológicos obtidos durante um período de nove semanas. Utilizaram-se cinco grupos de 43 leitões, com pesos de até 19kg, considerados de baixa performance. Estimaram-se, por intervalos de confiança de 95%, as prevalências acumuladas em cada monitoramento. Obteve-se correlação de 0,99 (P<0,0001) entre as prevalências anuais com as nove semanas de estudo, mostrando correspondência com o achado em matadouro. Amostras em semanas alternadas de três grupos de 43 animais são bons indicadores das patologias que afetam os suínos em crescimento, mesmo aquelas de baixa freqüência ou muito letais.

The prevalence of different pathologies as an indicator of health problems in a particular population by means of slaughterhouse monitoring of growing pigs was determined. The work was carried out in an indoor intensive farrow to finish swine farm during 9 weeks. The prevalence of diseases was determined by means of clinical and pathological diagnosis. For the slaughterhouse inspection, five groups of 43 pigs each weighting up to 19kg, considered as poor performers, were put together. These animals were sent to the slaughterhouse and were observed for the presence or absence of skin and joint lesions of arms and legs and also lesions of serous membranes and parenchimal organs. An estimative with a confidence interval level of 95% was performed on cumulated prevalence in each monitoring session for 43, 86, 129, 172 and 215 animals. Annual prevalence from clinical and pathological diagnosis and 9-week-period had correlations (r=0.99; P<0.0001) and correspondence with slaughterhouse observations. In conclusion, samplings in alternate weeks of three groups of 43 pigs seem to be a good indicator of pathologies affecting growing swines, even those of very low prevalence or highly lethal.

The goal of this work was to find a process to extract and separate carotene from natural sources using supercritical carbon dioxide. A high pressure extraction process was compared with a combined extraction-adsorption process. The experiments were performed with a pilot plant which can be operated up to 50 MPa and 100ºC. A technique using an on-line photometer, was used to estimate the concentration of carotenoids in the fluid phase, to monitor the different steps of the process. During the extraction of paprika powder, a time fractionation of pigments was observed: a low concentration fraction of free carotenoids at the beginning of the process and an enriched esterified carotenoid fraction at the end. With the combined extraction-adsorption process, using silica gel as adsorbent, a selective adsorption occurred. Red pigments (mainly esterified carotenoid) were adsorbed but the yellow ones (mainly free carotenoid) remained in supercritical phase which were collected in a separation step at lower pressure.

Supercritical CO2 extraction has shown great potential in separating vegetable oils as well as removing undesirable oil residuals from natural products. The influence of process parameters, such as pressure, temperature, mass flow and particle size, on the mass transfer kinetics of different natural products has been studied by many authors. However, few publications have focused on specific features of the raw material (moisture, mechanical pretreatment, bed compressibility, etc.), which could play an important role, particularly in the scale-up of extraction processes. A review of the influence of both process parameters and specific features of the material on oilseed extraction is given in Eggers (1996). Mechanical pretreatment has been commonly used in order to facilitate mass transfer from the material into the supercritical fluid. However, small particle sizes, especially when combined with high moisture contents, may lead to inefficient extraction results. This paper focuses on the problems that appear during scale-up in processes on a lab to pilot or industrial plant scale related to the pretreatment of material, the control of initial water content and vessel shape. Two applications were studied: deoiling of wheat gluten with supercritical carbon dioxide to produce a totally oil-free (< 0.1 % oil) powder (wheat gluten) and the extraction of oil from rose hip seeds. Different ways of pretreating the feed material were successfully tested in order to develop an industrial-scale gluten deoiling process. The influence of shape and size of the fixed bed on the extraction results was also studied. In the case of rose hip seeds, the present work discusses the influence of pretreatment of the seeds prior to the extraction process on extraction kinetics.