|Francis, G - CSIRO, AUSTRALIA|
|Phelps, P - EMBREX, INC, NC|
Submitted to: Poultry Science Association Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: August 8, 1997
Publication Date: N/A
Technical Abstract: An homologous RIA for chicken IGF-II has been developed to investigate plasma IGF-II concentrations in the developing chick and turkey embryos and during the post hatch period. The resulting RIA has a minimum detection limit of 0.078 ng and effective dose of 2.5 ng. Dose response curves of acid/ethanol extracted chicken and turkey plasma were parallel with cIGF-II standard. The antiserum is specific for IGF-II as no cross-reactivity with IGF-I, insulin or glucagon was observed. It was established that acid/ethanol extraction of chicken and turkey plasma reduced interference of IGF binding proteins in the RIA. Chick embryo plasma IGF-II concentrations ranged from 99ng/ml on Day 13 to 138 ng/ml on Day 21. In male broiler chicks, plasma IGF-II were elevated (35 to 50 ng/ml) during the first three weeks post hatch, and remained unchanged (35 ng/ml) for the remaining four week sampling period. In the turkey embryo plasma IGF-II varied from 20 ng/ml on Day 10 to 92 ng/ml on Day 26, and declining to 40 ng/ml at hatching. In the male turkey IGF-II concentrations were essentially similar from week 1 through week 20 post hatch. In 4-week old chickens plasma IGF-II increased from 55 ng/ml (fed state) to 92 ng/ml after 24 hrs of fasting. Levels remained elevated (75 ng/ml) after 48 hrs of fasting, and returned to pre-fasting concentrations after refeeding. Plasma IGF-II concentrations were similar in chickens fed either a low protein diet (53 ng/ml) or high protein diet (52 ng/ml). In summary, an homologous RIA has been developed for chicken IGF-II to monitor changes in circulating IGF-II during the embryonic and post hatch growth periods in chickens and turkeys.