Transcriptome Profiling Of Feeding-To-Fasting Transition In Chicken Liver Using A Chicken 20K Oligo Microarray

International audience

Inglés. Starvation triggers a complex array of adaptative metabolic responses including energy-metabolic responses, a process which must imply tissue specific alterations in gene expression profiles. In the chicken, liver is a major organ controlling energy metabolism. The present study aimed to describe the evolution of global gene expression profiles in chicken liver during a 48h fasting period. Liver RNA samples were collected from 4 weeks old broilers, fed ad libitum or fasted for 16h or 48h. Following reverse-transcription and Cy dye labelling, the samples were hybridized on chicken 20K oligochips (ARK-genomics) against a reference sample. The data were then normalized by “Lowess-fitness” and analyzed by analysis of variance using LIMMA package. The number of genes altered by fasting increased from 190 at 16h to 611 at 48h (p<0.0001 following Benjamini-Hochberg correction) showing a more important hepatic transcriptional activity modification when the fasting was extended. After 16h of fasting, several genes involved in mitochondrial or peroxisomal fatty acid beta-oxidation (eight of the nine genes), in ketogenesis (three genes) and gluconeogenesis (three genes) were up-regulated, whereas genes involved in fatty acid synthesis (five genes) were down-regulated. This is consistent with the known regulation of glucose and lipid metabolisms in response to nutritional deprivation, as documented in different species. Further analysis was focused on 600 genes, which were significantly differentially expressed between at least two nutritional groups and for which a human ortholog could be identified, thus allowing to collect functional informations. This allowed identifying Gene Ontology categories and metabolic pathways altered by fasting.