Microarray gene expression analysis of porcine skeletal muscle sampled at several post mortem time points.

A pilot study using Affymetrix Gene Chip(®) Porcine Genome Arrays was set up to evaluate the impact of time lags from death on gene expression profiling of porcine skeletal muscle at four post mortem times (up to 24h) during the routine processing of fresh thighs. All post chip parameters and data analyses (Average background, Scale Factors, Percent Presence, 3'/5' ratios of β-actin and glyceraldehyde-3-phosphase dehydrogenase control genes, RNA degradation diagnostics, principal component analysis, hierarchical clustering, mixed regression models with time effects) did not show any effect of post mortem time. Therefore, microarray data obtained from muscle specimens collected in a processing plan over a quite long period have the potential to identify treatments or pre mortem conditions without any potential bias derived from subtle RNA degradation. These results open new perspectives to develop and analyse gene expression biomarkers for pig production and product authentication.