Developmental origins of health and disease : importance in animal production
Résumé
The field of research on developmental programming has been increasing rapidly over the last 10 uears, especially in order to understand the responsability of programming and epigenetic adaptations in the currently observed epidemics of obesity, type 2 diabetes and cardiovascular diseases in the human population worldwide, leading to the birth of a scientific society centered around these aspects (Developmental Origins of Health and Disease, DOHaD, http://www.mrc.soton.ac.uk/dohad/). These effects initially observed in humans and animal models are shared by production animals. In the context of current global climatic changes, the breeding industry is required to adapt to an increasing incidence of biological hazards including temperature rise, increasing risks and severity of draughts, river flood disasters and decreased crop yields. These fluctuations are likely to cause irregularity in the quantity of forage and cereal yield and to induce quantitative and qualitative variations in the diet provided to the animals, with short or even long term periods of nutrition restriction. In production animals, these can results in long term physiological effets on health and reproductive parameters as well as on the quality and quantity of products. In horses, insulin resistance is recognized as an emerging disease linked to several major equine pathologies such as laminitis, hyperlipidemia, Cushing's disease, diabets, endotoxemia and osteochondrosis. Our group is currently exploring the role of fetal developmental conditions on offspring growth, glucose homeostasis and osteo-articular health, with recent data demonstrating the role of fetal growth on insulin resistance in these species. It is now widely admitted that long term effects of adverse developmental conditions are mediated through epigenetic mechanisms that modulate gene expression without modifying the genome. The placenta and the gametes may be considered as key tissues for bearing the epigenetic memory of the prenatal developmental conditions and are therefore the target of our future investigations.