Compromised nutrition in gerbils infected by Cystoisospora felis detected through an animal performance analysis tool.

The impact of Cystoisospora felis infection on the nutritional efficiency of gerbils was studied. The variables weight gain and feed intake were measured during four weeks in 28 laboratory gerbils, of which 14 were inoculated with 3.5 × 10(5) sporulated oocysts of C. felis and the remaining 14 were controls. The animals from both groups were weighted, killed, eviscerated and had their carcasses and tissues weighted and compared. A modern tool designed for measuring nutritional performance of farm animals was applied. The results showed compromised nutritional efficiency of the infected animals within the first week after infection. The consequences of these results are discussed here, including the potential impact of infection on farm animals performance.

Compromised nutrition in gerbils infected by Cystoisospora felis detected through an animal performance analysis tool / Comprometimento nutricional em gerbis infectados por Cystoisospora felis detectado através de uma ferramenta de análise de desempenho animal

The impact of Cystoisospora felis infection on the nutritional efficiency of gerbils was studied. The variables weight gain and feed intake were measured during four weeks in 28 laboratory gerbils, of which 14 were inoculated with 3.5 × 10(5) sporulated oocysts of C. felis and the remaining 14 were controls. The animals from both groups were weighted, killed, eviscerated and had their carcasses and tissues weighted and compared. A modern tool designed for measuring nutritional performance of farm animals was applied. The results showed compromised nutritional efficiency of the infected animals within the first week after infection. The consequences of these results are discussed here, including the potential impact of infection on farm animals performance.

O impacto da infecção por Cystoisospora felis na eficiência nutricional de gerbis foi estudado. As variáveis ganho de peso e consumo de ração foram mensuradas durante quatro semanas em 28 gerbis de laboratório, dos quais 14 foram inoculados com 3,5 × 10(5) oocistos esporulados de C. felis e os 14 restantes serviram como controle. Os animais de ambos os grupos foram pesados, mortos, eviscerados e tiveram suas carcaças e tecidos pesados e comparados. Uma ferramenta moderna desenvolvida para mensurar o desempenho nutricional de animais de produção foi aplicada. Os resultados mostraram eficiência nutricional comprometida dos animais infectados na primeira semana após a infecção. As consequências destes resultados são discutidas aqui, incluindo o possível impacto de infecção no desempenho de animais de produção.

Detection of Kluyveromyces marxianus and other spoilage yeasts in yoghurt using a PCR-culture technique.

A combined PCR-culture technique was developed for the detection of viable yeasts in yoghurt samples. Yoghurt samples were inoculated with either viable or heat-inactivated Kluyveromyces marxianus cells, and analyzed before and after incubation for 24 h at 25 degrees C under agitation. DNA was extracted from the samples and amplified using yeast-specific primers targeted at the gene coding for the 18S rRNA. A 251-bp fragment was amplified by the Polymerase Chain Reaction from the yoghurt samples containing initial yeasts counts of 10 cfu g(-1) or higher, whereas no PCR product was generated from control uninoculated yoghurt samples. Comparison of PCR results obtained before and after the incubation step was used to assess yeast viability. Viability was also confirmed by plating on Sabouraud-Dextrose-Chloramphenicol Agar. Moreover, comparison of the results obtained using PCR-culture and plate count methods for the analysis of commercial yoghurt samples, demonstrated that the PCR-culture technique developed in this work can be very useful for the rapid detection of viable spoilage yeasts in dairy industries.

Development of a PCR-culture technique for rapid detection of yeast species in vacuum packed ham.

A rapid assay for detection of yeast species in vacuum packed ham has been developed based on the polymerase chain reaction (PCR) coupled to a 24 h pre-enrichment at 25 °C. DNA was isolated from yeast inoculated ham samples and amplified using primers specific for the 18S rRNA gene sequences of yeasts. A detection limit of 10(2) CFU/cm(2) was achieved following enrichment of samples experimentally inoculated with three yeast species frequently associated with meat products spoilage: Debaryomyces hansenii, Yarrowia lipolytica, and Kluyveromyces marxianus. Likewise, commercial sliced and vacuum packed ham samples were analysed using the PCR-culture technique. The results obtained in this work show that PCR amplification of a conserved region of the 18S rRNA gene in the yeast species could be potentially used as a rapid tool for detection of low levels of viable spoilage yeasts in meat products.

Enumeration of yeasts in dairy products: a comparison of immunological and genetic techniques.

Enzyme-linked immunosorbent assay (ELISA) and PCR techniques have been developed for the detection of spoilage yeast species in dairy products. Polyclonal antibodies against live yeast cells (AY) were raised in rabbits by inoculation of a mixture of 10 yeast species frequently associated with dairy products spoilage. AY antibodies were used for the development of two ELISA formats (indirect and double-antibody sandwich ELISA) for the detection of yeast species in milk and yogurt. A PCR assay was also developed for yeast detection in dairy products, using primers designed to amplify a conserved 250-base pair fragment of the 18S rRNA of the yeast species. The results obtained in this work show that ELISA techniques using polyclonal antibodies against viable yeast cells are of limited value for the detection and enumeration of spoilage yeast species in dairy products. On the contrary, PCR amplification of a conserved region of the 18S rRNA of the yeast species allows the homogeneous detection of all the yeast species tested and, combined with an overnight enrichment of samples, could be used for the detection of low levels of viable spoilage yeast species in dairy products.