The Research Of Quality Chicken Selection Methods

With the rapid development of quality chicken industry in china, improving quality chicken production efficiency, along with reducing production costs had become the goal by all livestock enterprises. The breeders also expected to improve the breeding methods, and improve the utilization rate of poultry. In this experiment records data of 335 laying hens strain N502 obtaind from Wen's for the laying performance and the genetic parameters of the egg laying performance were used, to analyze and discuss the applicability of the method in the breeding process of the selection of two stages. In this study, the PRL gene was selected as a candidate gene, and 5 pairs of primers were designed to amplify the 5 'flanking region, 5' UTR, exon3 and intron2, to study the correlation between SNP loci and egg performance. In addition, we used three kinds of mathematical model to analysis the curve fitting of laying rate, to explore the effects of fitting mathematical model, and guiding significance to the production practice. The main results are as follows:The results of this experiment showed that the heritability of EN56 W was 0.053, and the heritability of EN46 W was 0.049. However, the result of genetic correlation coefficient of EN40 W, EN41 W, EN42 W, EN43 W, EN44 W, EN45 W, EN46 W compared with EN56 W were all above 0.90. The genetic correlation coefficient of EN40 W and EN56 W reached 0.999. Phenotypic correlation coefficients showed increasing trend. For example, the phenotypic correlation coefficient of EN46 W and EN56 W reached 0.937.When the general selection rate 30 % and the first phase of the selection rate unchanged, the selection effect is getting better with the delay of time and the correlation coefficient is also gradually increased. For example, at 40 % selection rate of the first stage, breeding value of correlation coefficient between EN40 W and EN56 W was 0.995(p < 0.01). When selection time of the first stage invariable, the selection effect was improved with selection rate increased. For example, when the first stage selection time is 40 weeks of age and the rate is 30 % of the selection,the correlation coefficient of EN40 W and EN56 W was 0.746(p < 0.01).This study found that 20 SNPs in PRL gene are T-2411C?T-2201C?G-2170C?G-2143C?G-2071C?A-2049G?A-1953G?A-1893C?A-1766G?A-1655G?A-1249G?T-746G?A245T?A271T?T1783C?T1809C?A1926G?A1975G?T2033C and T1870 G, but the result of correlation analysis shows, there was no significantly association between SNPs and egg production traits.In the egg production curve, the fitting analysis, Yang Ning model was found the best fitting effect, and the fitting degree was R2 = 0.992.