The use of reference genes is commonly accepted as the most reliable approach to normalize qRT-PCR and to reduce possible errors in the quantification of gene expression. The most suitable reference genes in sheep have been identified for a restricted range of tissues, but no specific data on whole blood are available. The aim of this study was to identify a set of reference genes for normalizing qRT-PCR from ovine whole blood. We designed 11 PCR assays for commonly employed reference genes belonging to various functional classes and then determined their expression stability in whole blood samples from control and disease-stressed sheep. SDHA and YWHAZ were considered the most suitable internal controls as they were stably expressed regardless of disease status according to both geNorm and NormFinder software; furthermore, geNorm indicated SDHA/HPRT, YWHAZ/GAPDH and SDHA/YWHAZ as the best reference gene combinations in control, disease-stressed and combined sheep groups, respectively. Our study provides a validated panel of optimal control genes which may be useful for the identification of genes differentially expressed by qRT-PCR in a readily accessible tissue, with potential for discovering new physiological and disease markers and as a tool to improve production traits (e.g., by identifying expression Quantitative Trait Loci). An additional outcome of the study is a set of intron-spanning primer sequences suitable for gene expression experiments employing SYBR Green chemistry on other ovine tissues and cells.

The aim of this study was to analyse the SPRN genes of goats from several scrapie outbreaks in order to detect polymorphisms and to look for association with scrapie occurrence, by an unmatched case-control study. A region of the caprine SPRN gene encompassing the entire ORF and a fragment of the 39UTR revealed a total of 11 mutations: 10 single-nucleotide polymorphisms and one indel polymorphism. Only two non-synonymous mutations occurring at very low incidence were identified. A significant association with scrapie positivity in the central nervous system was found for an indel polymorphism (602_606insCTCCC) in the 39UTR. Bioinformatics analyses suggest that this indel may modulate scrapie susceptibility via a microRNA-mediated post-transcriptional mechanism. This is the first study to demonstrate an association between the SPRN gene and goat scrapie. The identified indel may serve as a genetic target other than PRNP to predict disease risk in future genetics-based scrapie-control approaches in goats.

Major histocompatibility complex (MHC) loci encode glycoproteins that bind to foreign peptides and initiate immune responses through their interaction with T cells. MHC class II molecules are heterodimers consisting of α and β chains encoded by extremely variable genes; variation in exon 2 is responsible for the majority of observed polymorphisms, mostly concentrated in the codons specifying the peptide-binding region. Lactococcus garvieae is the causative agent of lactococcosis, a warm-water bacterial infection pathogenic for cultured freshwater and marine fish. It causes considerable economic losses, limiting the profitability and development of fish industries in general and the intensive production of rainbow trout, Oncorhynchus mykiss (Walbaum), in particular. The disease is currently controlled with vaccines and antibiotics; however, vaccines have short-term efficacy, and increasing concerns regarding antibiotic residues have called for alternative strategies. To explore the involvement of the MHC class II β-1 domain as a candidate gene for resistance to lactococcosis, we exposed 400 rainbow trout to naturally contaminated water. One single nucleotide polymorphism (SNP) and one haplotype were associated with resistance (P < 0.01). These results are promising for using MHC class IIβ as a molecular marker in breeding rainbow trout resistant to lactococcosis.

Species substitution is a common commercial fraud, mainly applied to fish species. It is thus important to have analytical methods for species identification. DNA analysis can be a suitable technique: some mitochondrial genes are actually recognized as valuable markers for species discrimination. Aim of this work was thus to evaluate the capability of cytb and COI genes to discriminate the species of fish (n=89) which are commonly substituted. In the last four years of activity on field, the laboratory analysed, using the FINS method (Forensically Informative Nucleotide Sequencing), 146 samples, belonging to several fish species, sent by veterinary officers in the frame of their activities of control: in this work, results about number and kind of fraud are reported. Additionally, samples directly purchased by the lab were examined. The obtained results showed that the genetic markers have a high discriminatory power and that the method is highly suitable. The frequent detection of species substitution in the samples collected on field showed the importance of controlling this kind of frauds in the fish market