The aim of this work was to study the occurrence of Listeria monocytogenes in several types of ready-to-eat (RTE) meat products and in the environment of meat processing plants. A total of 129 samples of RTE meat products and 110 samples from work surfaces and equipment were analyzed. L. monocytogenes was detected in 6 out of 35 cooked products (17.14%), 21 out of 57 raw-cured products (36.84%), and 9 out of 37 dry-cured, salted products (24.32%). The number of sample units that exceeded the food safety limit of 100 cfu/g decreased from the manufacture date to half shelf life, and then it was further reduced at the end of shelf life. L. monocytogenes was detected in 25 out of 110 (22.72%) food contact surfaces. The number of positive and negative results from both food and environmental samples were cross-tabulated and the calculated Cohen’s kappa coefficient (κ) was 0.3233, indicating a fair agreement in terms of Listeria contamination. L.
monocytogenes was recovered after cleaning and disinfection procedures in four plants, highlighting the importance of thorough cleaning and disinfection.
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Highlights Alfalfa lambs showed lower levels of SCD gene expression than indoors lambs. The SCD gene expression was affected by the rs412429481 SNP. The SCD promoter with the A allele had higher activity by luciferase and gene expression assays.A functional variant in the stearoyl-CoA desaturase (SCD) gene promoter affects gene expression in ovine muscle
A genome-wide association study (GWAS) was used to identify genomic regions influencing seasonality reproduction traits in Rasa Aragonesa sheep. Three traits associated with either ovarian function based on blood progesterone levels (total days of anoestrus and progesterone cycling months) or behavioral signs of oestrous (oestrous cycling months) were studied. The GWAS included 205 ewes genotyped using the 50k and 680k Illumina Ovine Beadchips. Only one SNP associated with the progesterone cycling months overcame the genome-wide significance level (rs404991855). Nine SNPs exhibited significant associations at the chromosome level, being the SNPs rs404991855 and rs418191944, that are located in the CD226 molecule (CD226) gene, associated with the three traits. This gene is related to reproductive diseases. Two other SNPs were located close to the neuropeptide Y (NPY) gene, which is involved in circadian rhythms. To validate the GWAS, partial characterization of both genes by Sanger sequencing, and genotyping of two synonymous and two nonsynonymous SNPs in the NPY and CD226 genes, respectively, were performed. SNP association analysis showed that only SNP rs404360094 in the exon 3 of the CD226 gene, which produces an amino acid substitution from asparagine (uncharged polar) to aspartic acid (acidic), was associated with the three seasonality traits. Our results suggest that the CD226 gene may be involved in the reproductive seasonality in Rasa Aragonesa.
The aim of this study was to characterize and identify causative polymorphisms in the leptin receptor (LEPR) gene responsible for the seasonal variation of reproductive traits in sheep. Three reproductive seasonality traits were studied: the total days of anoestrous (TDA), the progesterone cycling months (P4CM) and the oestrous cycling months (OCM). In total, 18 SNPs were detected in 33 ewes with extreme values for TDA and OCM. Six SNPs were non-synonymous substitutions and two of them were predicted in silico as deleterious: rs596133197 and rs403578195. These polymorphisms were then validated in 239 ewes. The SNP rs403578195, located in exon 8 and leading to a change of alanine to glycine (Ala284Gly) in the extracellular domain of the protein, was associated with the OCM trait, being the G allele associated with a decrease of 12 percent of the OCM trait. Haplotype analyses also suggested the involvement of other non-synonymous SNP located in exon 20 (rs405459906). This SNP also produces an amino acid change (Lys1069Glu) in the intracellular domain of the protein and segregates independently of rs403578195. These results confirm for the first time the role of the LEPR gene in sheep reproductive seasonality.
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