Relative levels of mRNA for selected genes associated with feeding and fasting in the hypothalamus as determined by microarray and qRT-PCR. Data were normalized to the housekeeping gene phosphoglycerate kinase 1 (PGK1), and are expressed relative to mRNA levels at hatch, which are set to the value of 1. Gene expression higher than 1 indicates upregulation compared to hatch, while gene expression levels less than 1 indicate downregulation compared to hatch. Treatment groups are designated as follows: hatch (H), fed for 24 h (24FF), fasted for 24 h (24NF), fed for 48 h (48FF), fasted for 48 h (48NF), fasted for 48 h then fed for 4 h (4DF), fed for 72 h (72FF), fasted for 48 h then fed for 24 h (24DF), fed for 96 h (96FF), fasted for 48 h then fed for 48 h (48DF). Genes evaluated were neuropeptide Y (NPY), agouti-related protein (AGRP), leptin receptor (LEPR), corticotropin releasing hormone (CRH), growth hormone releasing hormone (GHRH), thyrotropin releasing hormone (TRH), and melanocortin receptor 4 (MC4R). Black bars are microarray results, and white bars are qRT-PCR results. Values within a single method with differing letters are significantly different (P < 0.05).