Members of the B7 family costimulate the proliferation of lymphocytes during the initiation and maintenance of antigen-specific humoral and cell-mediated immune responses. While B7-1 and -2 are restricted to lymphoid tissues, and activate naïve T cells, recently identified members including B7-H2 and -H3 are widely expressed on nonlymphoid tissues, and regulate effector lymphocytes in the periphery. B7-H3 has properties that suggested it may display antitumor activity, including the ability to stimulate Th1 and cytotoxic T-cell responses. Here, we test this notion by determining whether intratumoral injection of an expression plasmid encoding a newly described mouse homologue of B7-H3 is able to eradicate EL-4 lymphomas. Intratumoral injection of a mouse B7-H3 pcDNA3 expression plasmid led to complete regression of 50% tumors, or otherwise significantly slowed tumor growth. Mice whose tumors completely regressed resisted a challenge with parental tumor cells, indicating systemic immunity had been generated. B7-H3-mediated antitumor immunity was mediated by CD8 + T and NK cells, with no apparent contribution from CD4 + T cells. In summary, the results indicate that B7-H3 interactions may play a role in regulating cell-mediated immune responses against cancer, and that B7-H3 is a potential therapeutic tool.
A meta-analysis was carried out in order to study the association of mycotoxins with performance and organ weights in growing pigs. A total of 85 articles published between 1968 and 2010 were used, totaling 1012 treatments and 13 196 animals. The metaanalysis followed three sequential analyses: graphical, correlation and variance-covariance. The presence of mycotoxins in diets was seen to reduce the feed intake by 18% and the weight gain in 21% compared with the control group. Deoxynivalenol and aflatoxins were the mycotoxins with the greatest impact on the feed intake and growth of pigs, reducing by 26% and 16% in the feed intake and by 26% and 22% in the weight gain. The mycotoxin concentration in diets and the animal age at challenge were the variables that more improved the coefficient of determination in equations for estimating the effect of mycotoxins on weight gain. The mycotoxin effect on growth proved to be greater in younger animals. In addition, the residual analysis showed that the greater part of the variation in weight gain was explained by the variation in feed intake (87%). The protein and methionine levels in diets could influence the feed intake and the weight gain in challenged animals. The weight gain in challenged pigs showed a positive correlation with the methionine level in diets (0.68). The mycotoxin effect on growth was greater in males compared with the effect on females. The reduction in weight gain was of 15% in the female group and 19% in the male group. Mycotoxin presence in pig diets has interfered in the relative weight of the liver, the kidneys and the heart. Mycotoxins have an influence on performance and organ weight in pigs. However, the magnitude of the effects varies with the type and concentration of mycotoxin, sex and the animal age, as well as nutritional factors.Keywords: aflatoxins, deoxynivalenol, nutrition, swine, trichothecenes ImplicationsThe mycotoxin effect on animal performance is recognized. However, this effect may be modified by several factors, which are noticeable in the large variability observed in previous results. This study is innovative, because it seeks to understand and quantify the interactions among mycotoxins and other factors such as nutrition, sex or growth phase of the pigs. The meta-analysis used the complementarities among previous studies in order to highlight gaps in mycotoxicology, which is hardly studied in traditional experimental designs. Furthermore, it aimed to assist in understanding the mycotoxin effects that this approach can support in the determination of dynamic growth standards for challenged animals.
A meta-analysis was carried out to study the association of mycotoxins with performance, productive indices, and organ weights in broilers. Ninety-eight papers published between 1980 and 2009 were used, totaling 1,401 diets and 37,371 animals. Meta-analysis followed 3 sequential analyses: graphical, correlation, and variance-covariance. The mycotoxin presence in diets reduced (P < 0.05) feed intake by 12% and weight gain by 14% compared with control group. Ochratoxins and aflatoxins were the mycotoxins with the greatest effect on feed intake and bird growth, reducing (P < 0.05) feed ingestion by 17 and 11%, respectively, and weight gain by 20 and 11%, respectively. The mycotoxin concentration in diets and the animal age at challenge were the variables that more improved the coefficient of determination for equations to estimate mycotoxin effect on weight gain. The mycotoxin effect on growth proved to be greater in young poultry. The residual analysis revealed that 65% of the variation in weight gain was explained by feed intake. The variation in weight gain of challenged broilers in relation to nonchallenged broilers was also influenced by ingestion of nutrients such as protein and methionine. Mortality was 8.8 and 2.8 times greater (P < 0.05) in groups that received diets with deoxynivalenol and aflatoxins, respectively. Mycotoxins also increased (P < 0.05) the relative weight of liver by 15%, of kidneys by 11%, of lungs by 9%, and of gizzard by 3%. Mycotoxins influenced broiler performance, productive indices, and organ weights. However, the magnitude of the effects varied with type and concentration of mycotoxin, animal age, and nutritional factors.
Milk fat enriched in conjugated linoleic and VAs suppresses inflammation and changes to the airways in an animal model of allergic airway disease.
Heat waves usually result in losses of animal production since they are exposed to thermal stress inducing an increase in mortality and consequent economical losses. Animal science and meteorological databases from the last years contain enough data in the poultry production business to allow the modeling of mortality losses due to heat wave incidence. This research analyzes a database of broiler production associated to climatic data, using data mining techniques such as attribute selection and data classification (decision tree) to model the impact of heat wave incidence on broiler mortality. The temperature and humidity index (THI) was used for screening environmental data. The data mining techniques allowed the development of three comprehensible models for estimating specifically high mortality during broiler production. Two models yielded a classification accuracy of 89.3% by using Principal Component Analysis (PCA) and Wrapper feature selection approaches. Both models obtained a class precision of 0.83 for classifying high mortality. When the feature selection was made by the domain experts, the model accuracy reached 85.7%, while the class precision of high mortality was 0.76. Meteorological data and the calculated THI from meteorological stations were helpful to select the range of harmful environmental conditions for broilers 29 and 42 days old. The data mining techniques were useful for building animal production models.
ABSTRACT:The relationship between thermal environment and chick performance has widely been evaluated, however the consideration that the assessment of the comfort may be estimated by interpreting both amplitude and frequency of bird vocalization under tropical housing conditions is a new concept. This research had as objective of estimating thermal comfort for chicks during the heating phase using this new concept. An experiment was carried out inside a climate controlled chamber (A) for establishing the behavioral pattern related to environmental temperature limits. Forty five chicks were reared inside a 2.3 m 2 box. A video camera was placed 2.0 m above the birds and the images were captured and registered in a computer. From the pattern determined in the controlled chamber an evaluation of the results was proceeded in a commercial broiler farm (experiment B) using similar bird density in order to validate the data. Environmental temperature, and both amplitude and frequency of the vocalizations of the chick group reared under heating were continuously recorded in both experiments. A correlation between group behavioral pattern and their vocalization, was found, evaluated not only by the noise amplitude but also by the noise frequency spectrum. When the thermal inertia is maintained by adequate use of curtains the birds vocalized less which is coincident with the low sudden variation of the temperature of the environmental. It was possible to estimate the thermal comfort for chicks at the heating stage by recording the amplitude and the frequency of the noise emitted by the reared group. Key words: broiler production, analysis of signals, thermal environment, behavior ANÁLISE DE RUÍDO PARA A AVALIAÇÃO DO CONFORTO TÉRMICO DE PINTINHOSRESUMO: A relação entre o ambiente térmico e o desempenho de pintinhos tem sido estudada, entretanto a consideração de que a medida de conforto térmico possa ser estimada pela interpretação da amplitude e da freqüência da vocalização, em condições tropicais de alojamento é um conceito novo. Esta pesquisa teve como objetivo estimar uma medida de bem-estar térmico para pintinhos em fase de aquecimento, pela medida de amplitude e freqüência do ruído emitido pelo grupo alojado. Inicialmente foi feito um experimento em câmara climática (A), para se estabelecer padrões de comportamento a partir de limites de temperatura ambiental. Foram alojados 45 pintos em um box de 2,3 m 2 . Uma câmera foi colocada a 2,0 m acima das aves e a captura das imagens foi registrada em um computador. A partir dos padrões determinados no primeiro experimento, foi feita uma avaliação desses resultados em uma granja comercial (experimento B) utilizando densidade de aves semelhante, de maneira a possibilitar uma validação. Foram medidas continuamente: a temperatura ambiental e a amplitude e freqüência de ruídos, do grupo de pintos alojados durante a fase de aquecimento em ambos experimentos. Houve correlação entre um padrão de comportamento de agrupamento e a vocalização, medida não somente pela amplitude do ru...
Climate may affect broiler production, especially where there are heat waves, which may cause high mortality rates due to the heat stress. Heat wave prediction and characterization may allow early mitigation actions to be taken. Data Mining is one of the tools used for such a characterization, particularly when a large number of variables is involved. The objective of this study was to classify heat waves that promote broiler chicken mortality in poultry houses equipped with minimal environmental control. A single day of heat, a heat-shock day, is capable of producing high broiler mortality. In poultry houses equipped with fans and evaporative cooling, the characterization of heat waves affecting broiler mortality between 29 days of age and market age presented 89.34% Model Accuracy and 0.73 Class Precision for high mortality. There was no influence on high mortality (HM) of birds between 29 and 31 days of age. Maximum temperature humidity index (THI) above 30.6 ºC was the main characteristic of days when there was a heat wave, causing high mortality in broilers older than 31 days. The high mortality of broilers between 31 and 40 days of age occurred when maximum THI was above 30.6 ºC and maximum temperature of the day was above 34.4 ºC. There were two main causes of high mortality of broilers older than 40 days: 1) maximum THI above 30.6 ºC and minimum THI equal or lower than 15.5 ºC; 2) maximum THI above 30.6 ºC, minimum THI lower than 15.5 ºC, and the time of maximum temperature later than 15:00h. The heat wave influence on broiler mortality lasted an average of 2.7 days
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