Study On The Regulation Of IGFs Changes And Relation Between The Polymorphism Of IGF-2 Gene And The Development During The Midanaphase Of Chicken Embryo

IGFs play a key role during the chicken embryo, development, differentiation and growth afterbirth. At present, researches are mostly concentrated on postnatal and few on embryonic stage. Meanwhile, there are controversial ideas on the result about the regulation of IGFs changes during the embryo stage of poultry. The regulation of IGFs changes during the embryo stage of New Yangzhou chicken were determined with ELISA in this study. At the same time, the polymorphism of different gene segment of IGF-2 with PCR-SSCP and the population heredity for SNPs were also detected and analysed. Simultaneity, the effect of gene variation on growth of chicken embryo was elementarily discussed. The result showed that:1. The embryo, heart, liver, muscular stomach, glandular stomach, intestines weight and shank bone length linearly increased with the age increasing since 9.5d.2. The research on regulation of IGFs changes during chicken embryo development showed: the concentration of IGF-1 was minimum in 11.5d and then increased to the maximal level in 15.5d, then declined. The concentration of IGF-2 was maximal in 10.5d and then decreased to the lowest level in 19.5d. The concentration of IGF-1 during the anaphase (15.5-19.5d) was very significantly higher than the one during the prophase(9.5-14.5d) of embryo development (P<0.01). Meanwhile, the concentration of IGF-2 during the midterm was higher than the one during the later period.3. Three sites of IGF-2 of New Yangzhou chicken had been detected in this study. The result of sequence detection indicated that there were insertion mutation C (P3), transition mutations C-G (P1), T-A (P2) and G-T (P2) and transition mutation T-C (P3).4. The polymorphism sites was analysed with genotypic frequency, gene frequency and genotypic distribution. It was found that these were much more different for P2 and P3 mutational sites, but relatively uniformity for P1 mutational site. The genotypic distribution was very significantly different among population with P1 and P3 mutational site (P<0.01) and they were not in Hardy-Weinberg balanced condition. The gene frequency and genotypic distribution were not significantly different among population with P2 mutational site (P>0.05), but they were in Hardy-Weinberg balanced condition. Meanwhile, it was in a lower level by analysis of polymorphism of genetic heredity5. The polymorphism of IGF-2 gene detected in this research had different effect on chicken embryo development. Through comparison and analysis of growth parameters with LSD, the result showed that for mutational site P1, the effect of genotypic AB was larger than AA which followed by BB. For mutational site P2, the effect of genotypic BB was larger than AB which followed by AA. For mutational site P3, the effect of genotypic BB was larger than AA which followed by AB. For mutational sites P1 and P2, the mutant individuals grew faster than wild-type ones. For mutational site P3, the wild-type individuals grew faster than mutant ones. It was inferred that the mutational sites P1 and P2 had some promotion to the development of chicken embryo. In a word, IGF-2 gene would be the major gene to the chicken growth trait or would link with the major gene which controlled the trait.