Chickens Genetically Selected For High Or Low Juvenile Body Weight Display Differences In Glucose Tolerance And Insulin Sensitivity

Chickens selected for high (HWS) or low (LWS) juvenile body weight (BW) for 55 generations differ by 12‐fold in BW at 56 days of age and display differences in appetite and body composition. We hypothesized that HWS display impaired glucose tolerance and are relatively insulin resistant. At 58 days of age, overnight fasted HWS and LWS (N = 12) were orally administered glucose (2 g/kg BW) and whole blood glucose (BG) was measured at 0, 5, 15, 30, 60, 120, 240 and 300 min relative to glucose infusion. At 66 days, the same fasted chickens were injected intra‐peritoneally with 80 μg insulin/kg BW and BG was measured at 0, 5, 15, 30, 60, 120, and 180 min relative to injection. The area under the curve for the glucose tolerance test was greater ( P = 0.05) in HWS than LWS, suggestive of impaired glucose tolerance in HWS. For the insulin sensitivity test, there was an effect of genetic line (HWS >; LWS; P < 0.0001) and the interaction of line by time ( P = 0.04) on BG, where HWS values were greater than LWS from 0 to 60 min and lower at 120 min. These data suggest that selection for juvenile body weight in chickens leads to differences in glucose homeostasis and insulin sensitivity.