| Insulin-like growth factor-1 (IGF-1) is important positive modulators of muscle and skeleton growth. But whether or not the genetic variations in IGF-1 gene have direct effects on growth and muscle traits is still a subject not well defined. For this reason the genetic variation of the 5'region of the IGF-1 gene in NewYangzhou chickens was detected by means of Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The traits of growth of body and skeleton at 0~12weeks, the slaughter traits, the meat quality, the concentrations of serum IGF-1 and hormone related growth and the expression of IGF-lmRNA in muscle at 12weeks were measured .The relationship between DNA polymorphisms that revealed by PCR-RFLP and traits measured in this experiment were analyzed with linear model. The results were as showed:1.There were three genotypes (-/- +/-, and +/+) after the IGF-1 gene promoter sequence PCR products were cut by Pst1 enzyme, The frequencies of -/- +/- and +/+ genotype were 16%, 45.33%, and 38.67%.2.There was a tendency that the IGF-1 gene promoter sequence Pst1(-) allele association with conformation of meat-type chicken that have higher body weight and relative shorter length of body measurement, while the Pst1(+) allele have a reverse tendency. The Pst1(-/-)genotype was associated with a significantly higher body weight than Pst1(+/+)genotype at 2, 4, 8, 10and12-weeks when analyzed in total (p<0.05), The trend of cumulate growth of shank is the same with the trend of body weight between the genotypes, but the Pst1(-/-)genotype associated with a significantly lower absolute growth of shank at 10~12-weeks. So Pst1(-/-)genotype was associated with a significantly higher rate of body weight per centimeter of shanks than thePst1(+/+)genotypes at 12 week (P<0.05) .3.Any statistical significance was not observed for all viscera weights among genotypes except for the percentage of liver (p<0.05).4.The effects of genotypes on traits displayed the characteristic of varied with gender, age, and tissue: body weight of male have a trend of'-/-" ≥ "+/-"≥ "+/+", but the body weight of female have the trend of+/-" ≥"-/-"≥ "+/+". There were the interactions between genotypes and gender in some traits; the Pst1(-/-)genotype have a positive effects on body weight, while it have a negative effects on absolute growth and relative growth of shank at 10~12-weeks(p=0.03). The chicken with Pst1(+/-)genotype to be fastest on absolute growth of shank in all genotypes at 0~6-weeks, but the Chicken with Pstl (+/+)genotype to be fastest at 6~12-weeks.5.The ANOVA revealed the significant effect of the Pstl genotype on the concentrations of muscle phosphorus (p=0.04), the degree of muscle tender (p=0.001), and the diameter of muscle fiber(p=0.076). And there is no statistical significance effect of the Pstl genotype on the other traits of the meat quality measured in this experiment(p>0.1).6. The least square analysis showed that the IGF-1 gene promoter sequence Pst1(-/-)genotype chickens had significantly higher the leg and thigh muscle weight, beast muscle weight, and carcass net weight than Pst1(+/+)genotype chickens(p<0.05) . The Carcass ratio is reverse(p=0.033). The carcass net ratio, leg and thigh muscle ratio, and beast muscle ratio had no statistical significantly difference among genotypes (p>0.1),7. Although the +/- genotype chanticleers express a significantly higher serum IGF-1 concentration than the +/+ genotype chanticleers, there was no conformability between the trend of changes of IGF-1 concentration and the trend of changes of growth traits measured in this experiment among genotypes. Further more, the relative study shows no the relativity in the IGF-1 concentration and other traits(p>0.413), except for serum IGF-1 concentration and concentrations of muscle phosphorus (r=0.263. p=0.025) as well as serum IGF-1 concentration and serum insulin concentration(r=-0.298, p=0.021) . So we can conclude that serum IGF-1 concentration and the traits of growth did not correlated; IGF-1 P...
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