Submitted to: Poultry Science
Publication Type: Abstract Only
Publication Acceptance Date: May 31, 2004
Publication Date: June 1, 2004
Citation: Karcher, D.M., McMurtry, J.P., Applegate, T.J. 2004. Concentrations of insulin-like growth factors I and II in embryonic fluids of chickens, ducks, and turkeys [abstract]. Poultry Science. 83 (Suppl. 1):420.
Insulin-like growth factors (IGF-I, IGF-II) are present in the amniotic fluid of developing mammals and ingestion of the amniotic fluid has been shown to potentially impact the proper development of the gastrointestinal tract. To investigate IGF-I and 'II changes in avian embryo fluids, 250 duck eggs, 200 turkey eggs, and 222 chicken eggs were incubated, and the embryos were staged according to Hamburger and Hamilton's classification (1951). Amniotic and allantoic fluid IGF-I and -II concentrations were determined by radioimmunoassay. When the beak was prominent on the embryo, stage 29, the mean IGF-I concentration (conc.) of the chicken amniotic fluid was 97.9% greater than the mean turkey conc. and 81.5% greater than the mean duck conc. (P ' 0.05). At stage 40, when the external features are complete, the chicken amniotic fluid IGF-I conc. was 34.6% greater in the duck amniotic fluid and 17.5% greater than in turkey amniotic fluid (P ' 0.05). However, at stage 37 and 38 (eye-lids narrow and leg scales appear) the IGF-I conc. in turkey amniotic fluid was 70-80% higher compared to the chicken or duck conc. (P ' 0.05). Within species, amniotic IGF-I conc. were low at stage 29 with maximum conc. occurring at the time of imbibing (stage 42 duck and turkey; stage 44 for chicken). The amniotic IGF-I conc. in the chicken had a cubic relationship (r2 = 0.41; P = 0.0003) with a 95% difference (P ' 0.05) between the lowest and highest conc. Duck amniotic IGF-I had a linear relationship (r2 = 0.73; P < 0.0001) with a 94% (P ' 0.05) difference observed between highest and lowest conc. The IGF-I conc. in the turkey amniotic fluid followed a similar trend with a quadratic relationship (r2 = 0.43; P = 0.0006) and an observed difference in minimum and maximum conc. of 98% (P ' 0.05). Amniotic fluid IGF-II was not significantly (P > 0.05) different across species. Overall, the conc. of IGF-I and 'II varies across and within specie.