Heat stress impairs egg production in commercial laying hens infected by fowl typhoid.

Salmonella Gallinarum (SG) is an avian-restricted pathogen that causes fowl typhoid in poultry. Although it has been reported frequently over many decades in poultry flocks worldwide, the microorganism is more commonly associated with poultry in developing countries, particularly those with high ambient temperatures, where the acute form of the disease results in considerable economic losses. A more detailed investigation of environmental factors that affect the course of disease may assist in identifying effective prevention and control measures. Heat stress is known to impair the immunological response to a variety of pathogens and clearly may be an important contributory factor in the prevalence of disease in countries with warm or hot climates. Thus, the objective of the present study was to evaluate the effects of heat stress on chickens infected with SG. For this, light and semi-heavy commercial laying hens were distributed randomly within four groups as follows: infected and non-infected groups in rooms held at ambient temperature, and infected and non-infected groups under heat stress. Clinical signs, egg production, and mortality were recorded daily. Bacteriological counts in liver and spleen samples were estimated at 2, 5, 7, and 14 days post-infection. The results showed that both SG infection and heat stress had similar effects on egg production and a synergistic effect of the two stressors was observed. The data show an interaction between disease and heat stress which could point towards environmental and biosecurity approaches to resolving the possible 30% fall in production observed in such countries.

Características definidoras da Resposta Disfuncional ao Desmame Ventilatório como indicadores de acurácia do desmame ventilatório / Defining characteristics of the Dysfunctional Ventilatory Weaning Response as indicators of accuracy of ventilatory weaning / Características definitorias de la Respuesta Disfuncional al Destete Ventilatorio como indicadores de precisión del destete ventilatorio

Objetivou-se avaliar as características definidoras do diagnóstico Resposta Disfuncional do Desmame Ventilatório, como indicadores de acurácia das tentativas de desmame. Estudo observacional de 38 eventos de tentativa de desmame ventilatório em pacientes adultos internados em terapia intensiva. Para as características definidoras foram calculadas: sensibilidade, especificidade, valores preditivos positivos e negativos, acurácia ou sensibilidade, razão de verossimilhança e razão de chances diagnóstica. Também foram consideradas as medianas do número de características definidoras nos eventos de sucesso e insucesso. Foram consideradas acuradas: agitação, deterioração nos gases sanguíneos arteriais em relação aos parâmetros basais, uso moderado da musculatura acessória da respiração, aumento da frequência respiratória em relação aos parâmetros basais e frequência respiratória aumentada de forma significativa em relação aos parâmetros basais. Houve diferença estatística nas medianas do número de características definidoras observadas. Conclui-se que a característica definidora e o número delas influenciariam o sucesso da decisão sobre o desmame.

The study aimed to analyze the defining characteristics of the Dysfunctional Ventilatory Weaning Response as an indicator of the accuracy of ventilatory weaning. Observational study of 38 events of ventilatory weaning in adult patients admitted to intensive care. For the defining characteristics, it was calculated: sensitivity, specificity, positive and negative predictive values, accuracy or efficiency, likelihood ratio positive and negative, and diagnostic odds ratio. It was also considered the median number of defining characteristics in the event of success and failure. It was considered accurate: agitation, deterioration in arterial blood gases from baseline parameters, moderate use of accessory muscles of respiration, increased respiratory rate from baseline parameters and respiratory rate increases significantly with respect to baseline parameters. There was statistical difference in the median number of defining characteristics observed. It was concluded that the defining characteristic and the number of them would influence the success of the weaning decision.

El estudio tuvo como objetivo evaluar las características que definen el diagnóstico de Respuesta Disfuncional al Destete Ventilatorio como indicador de la exactitud del destete ventilatorio. Estudio observacional de 38 eventos de destete ventilatorio en pacientes adultos ingresados en cuidados intensivos. Para las características definitorias se calcularon: sensibilidad, especificidad, valores predictivos positivos y negativos, precisión o sensibilidad, cocientes de probabilidad y odds ratio diagnóstica. Fueran consideradas las medianas del número de características definitorias en casos de éxito o de fracaso. Se consideraron precisas: agitación, deterioro de los parámetros de gases en sangre arterial desde la línea de base, uso moderado de los músculos accesorios de la respiración, aumento de la frecuencia respiratoria a partir de parámetros de línea de base y frecuencia respiratoria aumentada significativamente en comparación con los parámetros de línea de base. Hubo diferencia estadísticamente significativa en la mediana del número de características definitorias observadas. Se concluye que la característica definitoria y el número de ellas influyen en el éxito de la decisión sobre el destete ventilatorio.

Heat stress impairs performance and induces intestinal inflammation in broiler chickens infected with Salmonella Enteritidis.

Stressful situations reduce the welfare, production indices and immune status of chickens. Salmonella spp. are a major zoonotic pathogens that annually cause over 1 billion infections worldwide. We therefore designed the current experiment to analyse the effects of 31±1°C heat stress (HS) (from 35 to 41 days) on performance parameters, Salmonella invasion and small intestine integrity in broiler chickens infected with Salmonella Enteritidis. We observed that HS decreased body weight gain and feed intake. However, feed conversion was only increased when HS was combined with Salmonella Enteritidis infection. In addition, we observed an increase in serum corticosterone levels in all of the birds that were subjected to HS, showing a hypothalamus-pituitary-adrenal axis activation. Furthermore, mild acute multifocal lymphoplasmacytic enteritis, characterized by foci of heterophil infiltration in the duodenum, jejunum and ileum, was observed in the HS group. In contrast, similar but more evident enteritis was noted in the heat-stressed and Salmonella-infected group. In this group, moderate enteritis was observed in all parts of the small intestine. Lastly, we observed an increase in Salmonella counts in the spleens of the stressed and Salmonella-infected chickens. The combination of HS and Salmonella Enteritidis infection may therefore disrupt the intestinal barrier, which would allow pathogenic bacteria to migrate through the intestinal mucosa to the spleen and generate an inflammatory infiltrate in the gut, decreasing performance parameters.

Bacillus cereus var. toyoii and Saccharomyces boulardii increased feed efficiency in broilers infected with Salmonella enteritidis.

1. The effect on feed efficiency of two probiotics, one prepared with Saccharomyces boulardii and the other with Bacillus cereus var. toyoii, was tested in broilers infected with Salmonella enteritidis. 2. One-day-old chicks were divided at random into three groups and fed commercial feed devoid of antibiotics: group 1 was fed with non-supplemented feed, group 2 was supplemented with S. boulardii and group 3 with B. cereus. At 14 d of age the animals were challenged by the oral route with 1 x 10(7) viable S. enteritidis. 3. At d 47, average live weights were: group 1, 1.77 kg, group 2, 1.89 kg and group 3, 2.06 kg, and were significantly different. Feed conversion rates were 2.61 for group 1, 2.35 for group 2 and 2.30 for group 3. 4. We conclude that both probiotics improved feed efficiency in broilers.