Abstract
The polymorphism of insulin-like growth factor I (IGF I) in 6 chicken breeds (total n=515) was detected by PCR-Pst I- RFLP, and allele A (621 bp) or allele B (364 and 257 bp) were observed. In these chicken breeds, it was found that exotic chicken carried high frequencies of allele B, while Chinese native chicken breeds carried high frequencies of allele A. Meanwhile the role of IGF I was investigated in 133 Ningdu Yellow chicken and 162 Wanzhai Yellow chicken. Five growth traits were recorded for analyzing the association between IGFI gene polymorphism and performance. In both the Ningdu and Wanzhai Yellow breeds, body weight at 4 months was significantly higher with BB genotype than with AA genotype (p<0.05). Furthermore, body weight at 2 months in the Wanzhai Yellow breeds was also higher with BB genotype than with AA genotype (p<0.05). There were no differences among the genotypes for the other traits studied. Based on these results, it is necessary to do more studies on IGFI before making the IGFI locus into the application of maker-assisted selection programms. (Asian-Aust. J. Anim. Sci. 2004. Vol 17, No. 3 : 301-304)
Highlights
As growth in Chicken is highly regulated by growth axis, recent work revealed the mechanism of signal pathway from the release of growth hormone (GH) from pituitary to the expression of animal growth
The signal transduction commenced from the binding of GH to its receptor can active a specific gene coding insulin-like growth factor I (IGF I)
In order to detect the effects of different IGF I genotypes on some growth traits, we investigated Ningdu Yellow chickens (n=133, Jiangxi Province Ningdu Yellow Seed Farm) and Wanzhai
Summary
As growth in Chicken is highly regulated by growth axis, recent work revealed the mechanism of signal pathway from the release of growth hormone (GH) from pituitary to the expression of animal growth. The signal transduction commenced from the binding of GH to its receptor can active a specific gene coding insulin-like growth factor I (IGF I). Some literatures pointed out an important role for IGF I in the control of growth and metabolism in chicken, as in mammals. The effects of IGF I gene variants on performance traits had been described for mouse (Collins et al, 1993; Horvat et al, 1995) and pig (Casas-Carrillo et al, 1997; Wang et al., 2002). In this study we investigated the polymorphism of IGF I in six chicken breeds and the effects of one IGF I restriction fragment length polymorphism (RFLP) described by Nagaraja et al (2000) on growth traits in Ningdu Yellow chickens and Wanzai Yellow chickens
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