| Reproductive performance and egg quality play an important role in layer production for close links to production efficiencies and profits. Thus, more and more attentions focus on improvement egg production and quality. In this study, G4and G5of Rugao yellow chicken are selected as experiment animals. We compared the difference on hatchability, reproductive performance and egg quality between two generations. Genetic parameters on reproductive performance and egg quality were estimated by SPSS17.0. Four genes, i.e. VIP, VIPR-1, FSHR and ESRa gene, were picked out as candidate genes for egg production and quality. SNPs were identified by the MALDI-TOF-MS. Linkage disequilibrium between loci was estimated by an online software-SHEsis. The association egg production and quality with haplotype were analyzed with PHASE V2.1. The results were shown as following:1. Hatch test suggested fertility, hatchability of setting eggs, healthy chicks of fertile eggs and setting eggs in5th generation was more1.49%,2.71%,2.24%,0.85%than that of4th generation. However, the embryo mortality in5th generation was less2.97%than that of4th generation.2. Comparison of egg production and quality between two generations suggested:Body weight at the age of the first egg and40weeks in5th generation was less6.31%,7.74%than that of4th generation(P<0.05). The number of egg in40weeks in5th generation was more3.48%than that of4th generation(P<0.01). Eggshell strength, york color and hugh’s units in5th generation was more16.06%(P<0.01),3.25%(P<0.05),3.62%(P<0.01) than that of4th generation. However, egg shape index and egg shell color in5th generation was more2.13(P<0.05),5.89(P<0.01) than that of4th generation.3. The day at the first egg showed a high heritability (0.470)in4th generation. Body weight at the age of the first egg and40weeks and the first egg weight showed a medium heritability (0.237～0.307)in4th generation. The number of egg in40weeks in4th generation had a low heritability (0.177). In5th generation, body weight at the age of the first egg and40weeks and the day at the first egg had a medium heritability (0.224～0.329), and the first egg weight and the number of egg in40weeks had a low heritability(0.167～0.150). In all, the day at the first egg, body weight at the age of the first egg and40weeks and the number of egg in40weeks belong to high, middle, and low heritability traits, respectively.4. There is a positive genetic correlation (0.003～0.842) within the day at the first egg, body weight at the age of the first egg and40weeks and the first egg weight. There is a negative genetic correlation (-0.510～-0.188) between the number of egg in40week and body and egg weight at the first egg and the day at the first egg. There is a negative correlation both in genetic and in phenotypic between egg size and egg shape index and egg shell strength, between egg shape index and egg shell color, weight and thickness, between egg shell color and egg shell strength, thickness and weight. There is a positive correlation both in genetic and in phenotypic among egg shell thickness, strength and weight.5.14SNPs were found in no-coding region of four candidate genes. Six loci deviated from Hardy-Weinberg equilibrium, i.e. C29329A, C30582G and G32281A in FSHR, C10593T and C42913T in VIPR-1, C800T in VIP.6. Three loci in FSHR were found in linkage equilibrium. Four loci in VIPR comprised of13genotypes and nine haplotypes. Three loci in ESRa comprised three haplotypes and five genotypes. Four loci in VIP comprised of four haplotypes and seven genotypes. 7. Studies associated performances with haplotypes suggested:A5A5and A5A6in VIPR-1were dominant haplotypes for reproductive performance; A5A6and A8A9in VIPR-1were dominant haplotypes for egg quality; C2C2in ESRa was dominant haplotype for reproductive performance and egg quality in Rugao yellow chicken. D1D4and D2D4in VIP were dominant haplotypes for reproductive performance and egg quality in Rugao yellow chicken. |
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