PrenatOdor - Positive prenatal olfactory learning: a strategy to improve the welfare and health of pigs in conventional pig farming?

Context and challenges

In conventional pig farming, the environment is often poor and monotonous, which can lead to boredom and have deleterious consequences on the well-being of the animals and their offspring. Numerous studies have shown that odours facilitate certain behaviours (food acceptability, object exploration) in different species, and some suggest that they can modulate the immune function (action on inflammation). The use of odours could therefore be an effective strategy to stimulate the animal, and thus improve its mental and physical health on farms. Furthermore, prenatal sensory experiences can have a lasting impact on the development of the young. In particular, foetuses are able to perform robust olfactory learning that impacts their olfactory preferences and, in pigs, re-exposure at weaning to an odour learned during foetal life stimulates food intake and growth and reduces deleterious social behaviour. These olfactory learnings would also be impacted by the contextual value of the odour, suggesting that the prenatal association between an odour and a positive context could optimize the observed benefits on long-term well-being or health in the offspring. Gestational programming processes are regulated in part by long-term epigenetic modifications, such as DNA methylation, which allow information about environmental conditions to be passed on to future generations. Nevertheless, little is known about the impact of positive prenatal experiences on epigenetic plasticity, and a limited number of studies have been conducted in farmed species. Yet, the identification of genes or pathways targeted by these epigenetic modifications could provide long-term markers of prenatal experiences and serve as a lever for improving the health and immunity of farm animals. The PrenatOdor project will therefore aim to generate knowledge on the effectiveness of a strategy based on prenatal olfactory enrichment to improve animal health and welfare in livestock, using a multi-disciplinary approach combining ethology, immunology and epigenetics. 

Objectives

1. To evaluate the effects of gestational exposure to an odour, coupled with a positive environmental context for the mothers, on the health and well-being of their piglets when they are re-exposed to this odour at weaning;
2. To identify transcriptional and epigenetic changes associated with these effects in immune blood cells of piglets.

Species concerned

Partnerships

• Joint research unit PEGASE, INRAE, PHASE division: ethology, endocrinology, immunology
• Joint research unit BREED, INRAE, PHASE division: epigenetics, ethology, bio-statistics
• Joint research unit BIOEPAR, INRAE, SA division: immunology
• UE3P, INRAE, PHASE division: breeding management, welfare in pig farming
• Phodé (industrial partner): formulation of aromas, analyses of aromatic compounds