Fasting and refeeding impacts on piglet jejunal transcriptome during weaning period

At weaning acute modifications of intestinal functions are largely explained by variations in feed intake. However, less is known on involved molecular mechanisms. In the present study, original porcine arrays associated with real time PCR analyses were used to assess global gene expression changes in the jejunum of piglets at weaning. Expression profiles of 954 distinct genes were compared in (i) sow-reared piglets slaughtered at 21 d of age, (ii) 21 d sow-reared piglets fasted for 2 days prior to slaughter at 23 d of age, or (iii) 21 d sow-reared piglets fasted for 2 days and refed ad libitum a starter diet prior to slaughter at 28 d of age. A total of 146 EST (87 annotated genes) differentially expressed between groups were sorted into 5 clusters of distinct expression profiles. A cluster of genes down regulated in both fasted and refed piglets is enriched for genes involved in cell adhesion and migration, digestive function and carbohydrate metabolism. A second cluster group genes down regulated in refed animals. Some of them are related to oxidative metabolism. A third cluster of genes up regulated in fasted animals is partly involved in cell proliferation, protein synthesis, and carbohydrate metabolism. The two remaining clusters include genes down regulated in fasted piglets or up regulated in refed animals, and group genes involved in cell proliferation, protein translation, amino acid metabolism and intestinal protection and restitution. These data highlight novel genes, the expression of which is influenced by fasting and refeeding during weaning period. However relationship between transcriptomic changes and modifications of physiological functions must be studied and further investigations are required.