Inter genotype differences in expression of genes involved in glucose metabolism in the establishment of hepatic steatosis in Muscovy, Pekin and mule ducks.

In waterfowls, overfeeding leads to a hepatic steatosis, also called "foie gras". Our main objectives were to determine what is the share of genes involvement of glucose metabolism in the establishment of fatty liver in three genotypes of waterfowls: Muscovy (Cairina moschata), Pekin ducks (Anas platyrhynchos) and their crossbreed, the mule duck. 288 male ducks of Pekin, Muscovy and mule genotypes were reared until weeks 12 and overfed between weeks 12 and 14. We analysed gene expression at the beginning, the middle and the end of the overfeeding period in different tissues. We have shown an upregulation of glucose transporters (GLUT) in peripheral tissues (pectoralis major or adipose tissue) in Pekin ducks. In addition, GLUT2 was not found in jejunal mucosa and another GLUT seems to replace it 3 h after the meal: GLUT3. Mule ducks upregulating GLUT3 earlier compared to Pekin ducks. However, these results need further investigations. In liver, globally, Pekin ducks exhibit the highest expression of GLUT or enzymes implicated in glycolysis. The few significant variations of gene expressions in glucose metabolism between these three genotypes and the momentary specific overexpression of GLUT do not allow us to detect a lot of specific genotype differences. To conclude, the differences in response to overfeeding of Pekin, Muscovy and mule ducks, for the establishment of hepatic steatosis, cannot be only explained by the glucose metabolism at transcriptomic level.