In ovo peptide YY and epidermal growth factor administration and their effects on growth and yolk utilization in neonatal meat-type chickens (Gallus domesticus)

The effects of in ovo peptide YY (PYY) or epidermal growth :factor (EGF) ad ministration on chick growth, yolk absorption and yolk stalk function in po sthatch (0-5 days) meat-type or broiler chicks were determined. At Day 18 o f incubation, treated eggs were injected into the air cell with 100 mul of either PYY (Trial 1) or EGF (Trial 2) at a dosage of 600 mug/kg egg weight. Saline-treated control eggs were injected similarly with 0.9% saline. At h atch, 200 mul of Cr-51-labeled microspheres were injected into chick yolk s acs: Epidermal growth factor increased ileal wet weight adjusted for body w eight as well as ileal serosal dry matter. Body weight, feed consumption an d excreta weight per bird, and relative weights of the yolk sac, intestine and liver were significantly affected by age of the chick in both trials. R elative radioactivity of the yolk sac, yolk stalk, blood, liver, and kidney s were affected by bird age in Trial 2; however, there were no significant effects due to PYY or EGF treatments on relative radioactivity of the tissu es and organs examined. These data suggest that PYY and EGF had no effect o n yolk absorption or yolk stalk function through 5 days in the posthatch ch ick. (C) 2001 Elsevier Science Inc. All rights reserved.