Perspectives offered by "omics" approaches to sustainable herbivore production.

The molecular mechanisms underlying biological processes are governed by the expression of many genes. The methods studying these complex processes have experienced tremendous technological advances over the past few years. Whereas in the past, molecular biology targeted a few genes chosen for their biological function, today, genomics, proteomics and metabolomics allow simultaneously studying a large number of genes, proteins or metabolites, irrespective of their biological function. These new technologies will help to improve our understanding of the herbivore biology in a context of sustainable production. This short review presents some examples showing how "omics" may contribute to the improvement of economic production efficiency based on, for instance, the detection of markers of exposure to mycotoxins or of the potential to improve the metabolic and physiological efficiency of herbivores (partitioning of nutrients between tissues and organs, muscle differentiation for meat production, nutritional regulation of the expression of genes). "Omic" approaches can also contribute to the other pillars of sustainability: animal well-being (by revealing stress markers), protection of the environment (by controlling nitrogen emissions from the animals), and product quality (by controlling the fatty acid composition of products and by finding biomarkers of meat tenderness, and of milk and meat flavour).