Abstract Real-time PCR (qPCR) has been used for rapid identification of Salmonella Typhimurium and Staphylococcus aureus in dairy foods, but is unable to differentiate viable and unviable pathogens. Ethidium bromide monoazide (EMA), a DNA-intercalating agent, can detect only viable cells because selectively enter cells considered unviable and bind to their DNA, inhibiting its amplification during qPCR. The objective was to establish a protocol for detection of viable Salmonella Typhimurium and S. aureus, experimentally inoculated in coalho cheese, by the use of EMA combined with qPCR. The protocol was effective for the identification of viable Salmonella Typhimurium in coalho cheese but not for the S. aureus cells. Concentrations of viable Salmonella Typhimurium cells of 1 CFU/10 g of coalho cheese could be detected. The monoplex protocol enables the rapid and specific identification of viable Salmonella Typhimurium in coalho cheese, making it an alternative method for the quality and safety control of cheeses.

Foi investigada a associação entre os polimorfismos de base única (SNPs) T2411C e T3266G da leptina e as características de carcaça em suínos F2 procedentes do cruzamento de machos da raça Piau com matrizes comercias de composição genética Landrace, Large White e Pietrain. As análises de associação foram feitas usando um modelo estatístico que incluía genótipo, sexo e lote como efeitos fixos, e pai e erro como efeitos aleatórios. O SNP T2411C esteve associado ao peso da copa sem pele e sem gordura (BSW), à espessura de gordura subcutânea na altura da última costela a 6,5 cm da linha média (P2), ao peso da paleta sem pele e sem gordura e ao peso do filezinho (SLW). O SNP T3266G foi associado a idade de abate, peso do bacon, BSW, espessura da gordura subcutânea entre a última e a penúltima vértebra lombar, na linha média, espessura da gordura subcutânea na altura da última costela na linha média, P2 e peso da costela. Os genótipos combinados para ambos os SNP estiveram associados a P2, peso total da copa, rendimento de carcaça e peso do filezinho. Os SNPs analisados têm potencial para ser explorados como marcadores para composição de carcaça em suínos.

It was investigated the association between leptin gene single nucleotide polymorphisms (SNPs) T2411C and T3266G with carcass traits in F2 pigs obtained by crossing native Brazilian Piau with commercial sows composed of Landrace, Large White and Pietrain breeds. Association analyses were performed using a statistical model that included genotype, sex, and batch as fixed effects, sire and error as random effects. The T2411C SNP was associated with skinless and fatless boston shoulder weight (BSW), backfat thickness at last rib, 6.5 cm from the midline (P2), skinless and fatless picnic shoulder weight, and sirloin weight (SLW). The T3266G mutation was associated with slaughter age, bacon weight, BSW, midline backfat thickness between last and last but one lumbar vertebra, midline backfat thickness at last rib, P2 and rib weight. Phenotypic associations were also performed by combining genotypes for both SNPs. Associations with P2, carcass yield, total boston shoulder weight, and SLW were observed. The results obtained demonstrate that the SNPs analyzed have potential to be explored as markers for carcass composition in pigs.

In order to characterize the expression of genes associated with immune response mechanisms to mastitis, we quantified the relative expression of the IL-2, IL-4, IL-6, IL-8, IL-10, IFN-γ and TNF-α genes in milk cells of healthy cows and cows with clinical mastitis. Total RNA was extracted from milk cells of six Black and White Holstein (BW) cows and six Gyr cows, including three animals with and three without mastitis per breed. Gene expression was analyzed by real-time PCR. IL-10 gene expression was higher in the group of BW and Gyr cows with mastitis compared to animals free of infection from both breeds (p < 0.05). It was also higher in BW Holstein animals with clinical mastitis (p < 0.001), but it was not significant when Gyr cows with and without mastitis were compared (0.05 < p < 0.10). Among healthy cows, BW Holstein animals tended to present a higher expression of all genes studied, with a significant difference for the IL-2 and IFN-γ genes (p < 0.001). For animals with mastitis no significant difference in gene expression was observed between the two breeds. These findings suggest that animals with mastitis develop a preferentially cell-mediated immune response. Further studies including larger samples are necessary to better characterize the gene expression profile in cows with mastitis.