Pancreatic Glucose Regulatory Gene Expression During The First Two Weeks Post-Hatch Differs Between Lines Of Chickens Selected For Low Or High Body Weight

Chickens from a common founder population, selected for low (LWS) and high (HWS) body weight (BW) for 55 generations, differ in BW by a factor >10. There are also high (HWR) and low (LWR) weight relaxed (random-bred since 46th generation). The objective was to evaluate the developmental regulation of pancreatic mRNA abundance in the genetic lines. At day of hatch (DOH) and days 1, 3, 7, and 15 (D1, 3, 7 and 15, respectively) post-hatch, pancreas was collected (n=12/line), total RNA isolated, and real time PCR used to measure mRNA abundance of pancreatic and duodenal homeobox 1 (PDX1), pre-proinsulin (PPI), pre-proglucagon (PPG), and glucose transporter 2 (GLUT2). Glyceraldehyde-3-phosphate dehydrogenase was the control. The statistical model included effects of line, age, and the 2-way interaction. Significance was assigned at P < 0.05 and Tukey's used for pairwise comparisons. There was an interaction of line by age on expression of all four genes (P < 0.02). Expression of PPI decreased from DOH to D1 and then increased to D15 in all lines, with greatest expression in LWS and LWR at D7, and lowest expression in HWS at D15 as compared to the other lines. PPG expression also decreased to D1 and then plateaued, with greatest expression in LWR at DOH, D3, and D15. For GLUT2, expression was also greatest at DOH compared to other ages in all lines and decreased to D1. Abundance of GLUT2 mRNA was greater in LWS and LWR than HWS and HWR at all ages. PDX1 expression was lowest at hatch and greatest at D15, with greater expression in LWS and LWR at D3 and D7 compared to the other lines. Expression of all genes changed with age and was greater in the low weight than high weight lines.