Effect of hen age on intestinal development and glucose tolerance of the Pekin duckling

Two experiments were conducted to determine whether hen age affects intestinal development and glucose clearance in Pekin ducklings after hatching. In Experiment 1, 85- to 92-g eggs were collected from 32- and 44-wk-old hens. The eggs from older hens contained proportionately more yolk, which resulted in a greater mass transfer of yolk sac DM and lipid from 21 to 25 d of incubation, and ducklings from older hens were heavier at hatching (P < or = 0.0001). Although the ducklings from the older hens were heavier at hatch, BW, feed consumption, and feed efficiency were not significantly different from 7 to 35 d of age. During the first wk after hatching, the age of the hen had no consistent effect on duodenum or lower small intestinal measurements (weight, length, or density). Hen age did not significantly affect plasma glucose concentrations at 0, 30, or 60 min post-injection of glucose (2.5 mg per g BW) in 3- or 6-d-old feed-deprived ducklings. In a second experiment, 85- to 90-g eggs were collected from 33- and 48-wk-old hens to determine whether differences in hen age caused a differential response to a challenge with a higher glucose dosage at 3 d of age. No differences between hen ages were apparent in plasma glucose concentrations at 0 or 30 min postinjection (3.75 mg glucose/g BW). At 60 min postinjection, however, the ducklings from the younger hens had 100.6 mg/dL greater plasma glucose concentrations than the ducklings from the older hens (P < or = 0.02). The glucose tolerance results suggest that differences in metabolism exist between ducklings from the younger hens, even though measurable BW differences did not exist.