ABSTRACT: Chickens divergently selected for either high growth (HG genotype) or low growth (LG genotype) by F.H. Ricard at SRA-INRA, Nouzilly France were used for time-course transcriptional profiling of abdominal fat during juvenile development (1 to 11 weeks of age) to identify differentially expressed genes. The HG and LG chickens are different in various phenotypic and metabolic measurements, including growth rate, abdominal fat, plasma glycemia, insulinemia, T4, T3, triglyceride and NEFA. Thus, the HG and LG chickens are valuable as a model for biomedical and agricultural traits. The Del-Mar 14K Chicken Integrated Systems microarrays were used for a transcriptional scan in abdominal adipose during juvenile development using a balanced block hybridization design. Log2-transformed fluorescence intensities were analyzed with the linear mixed model (MIXED) procedure in SAS (SAS Institute Inc., Cary, NC, USA). A total of 3,957 differentially expressed functional genes were identified (FDR<0.05) as having a significant effect of age (2,918), genotype (312), or an age by genotype interaction (727). The differentially expressed genes include adipokines, metabolic enzymes, acute phase proteins, growth factors, coagulation factors, immune factors and transcription factors involved in various pathways. Keywords: abdominal fat, divergently selected chickens, growth, transcriptional profiling, differentially expressed genes, lipogenesis A balanced block design was used for microarray hybridizations, where half of the birds of each genotype and age were labeled with Alexa Flour 647 (red) and the other half with Alexa Flour 555 (green). Four biological replicates were used for each genotype (HG or LG) at six different ages (1, 3, 5, 7, 9 and 11 wk).
