【作者】 廖冰；

【导师】 宁中华；

【作者基本信息】 中国农业大学 ， 动物遗传育种与繁殖， 2014， 博士

【摘要】 尽管影响孵化率的因素众多,本文试从蛋壳超微结构角度探讨影响孵化率的因素,在排除其他因素的影响下,研究蛋壳超微结构对孵化率的影响。利用MALDI-TOF MS对蛋壳超微结构候选基因SNP的基因型分型和关联分析,进一步了解影响蛋壳超微结构的遗传因素。本研究以洛岛白纯系蛋鸡400只为试验群体,通过蛋壳超微结构表型数据进行统计分析找出影响孵化率的因素。结果显示,蛋壳总厚度、乳突层厚度、有效层厚度和平均乳突大小均影响孵化率。蛋壳总厚度在324.5-364.5μm范围内具有较高孵化率。乳突层厚度范围在80.5-94.5μm的鸡蛋其孵化率最高。同样,有效层厚度在258.5-298.5μm范围内的蛋壳具有较高孵化率,蛋壳的平均乳突大小在76.5-87.5μm范围内,其孵化率更高。主成分分析表明,在蛋壳超微结构中,蛋壳总厚度和乳突层厚度可作为影响孵化率的主要因素。此外,平均乳突大小与蛋壳总厚度、乳突层厚度均呈中等的正相关。在试验中,晶体大小对孵化率没有影响,晶体取向结果显示所有样品都存在两个优势取向{104}和{018}。通过比较洛岛白两个品系的蛋壳超微结构来进一步揭示蛋壳超微结构对孵化率的影响。试验结果显示,品系2的蛋壳强度极显著高于品系1且具有较重的蛋壳重,其蛋壳总厚度和有效层厚度也极显著高于品系1。由于蛋壳总厚度与蛋壳强度正相关,因此有效层厚度的大小可能直接影响蛋壳强度。与品系1相比,品系2蛋壳强度大,并且具有较厚的微观结构。然而其孵化率较低,这说明过硬或过厚的蛋壳都不利于孵化。试验以洛岛白纯系蛋鸡68只亲代,417只子代为材料。使用DMU6.0软件包中的DMUAI模块对蛋壳超微结构的遗传力、遗传相关和表型相关进行估计。所估计的蛋壳总厚度、乳突层厚度、有效层厚度以及平均乳突大小的遗传力都很低。乳突层厚度和有效层厚度存在遗传的正相关和表型的负相关,蛋壳总厚度与乳突层厚度、有效层厚度间存在较高的正的遗传相关和表型相关。此外,平均乳突大小与蛋壳总厚度、乳突层厚度存在中等的正的遗传相关。利用MALDI-TOF MS对洛岛白蛋鸡的蛋壳超微结构候选基因SNP的基因型分型和关联分析,结果显示共有8个SNP位点(涉及4个基因)与蛋壳微观结构显著相关。Ovalbumin基因的与蛋壳总厚度和有效层厚度显著相关。Ovocleidin-116基因与乳突层厚度、有效层厚度和乳突大小均呈显著相关。Ovocalyxin-32与蛋壳总厚度显著相关。ChEST985k21基因与蛋壳总厚度和乳突层厚度显著相关。更多还原

【Abstract】 Though many factors affect the hatchability, this article tries from the angle of eggshell ultrastructure to explore the factors influencing hatchability. Expelling the role of other factors, we study the influence of eggshell ultrastructure organization on hatchability and genes.Eggshell quality is associated with hatchability, and ultrastructural organization is an important eggshell quality parameter. To the determine relationship of shell ultrastructural properties with hatchability, we measured the effect of Rhode Island White eggshell thickness, mammillary layer thickness, effective thickness and the average size of mammillary cones on hatchability. Egg had the highest incidence of hatching when total eggshell thickness was324.5-364.5μm. Mammillary layers range in80.5-94.5μm had the highest hatchability. As such, hatchability correlated positively with both eggshell thickness (r=0.30; P<0.05) and mammillary layer thickness (r=0.28; P<0.05). In addition, the correlation between the average size of mammillary cones and hatchability was not statistically significant. However, a significant positive correlation was observed between the average size of mammillary cones and mammillary layer thickness. It can be concluded that eggshell thickness and mammillary layer thickness affect hatchability. Crystallite size and crystallite orientation have no effect on hatchability. All samples have same two crystallite orientation:{104} and{018}.With respect to eggshell ultrastructural properties, two Rhode Island White strains were used to to determine the relationship of shell ultrastructural properties with hatchability. The strain2had thick shell, mammillary layer and effective layer compared to strain1. Eggs of strain2had significantly higher shell strength than strain1. As such, shell strength was very highly correlated with both eggshell thickness (r=0.82; P<0001) and effective thickness (r=0.82; P<0001). In addition, a significant difference in hatchability among eggs from different breeder flocks was found. Comparing to strain1, strain2breed was associated with a low incidence of hatching, suggesting that these eggshell ultrastructural properties could affect hatchability.In the analysis, all eggshell ultrastructure organization traits hold low heritabilities. Furthermore, the genetic and phenotypic correlations of the same egg quality traits including, eggshell thickness, mammillary layer thickness, the average size of mammillary cones are positive.Twenty-three candidate SNPs from4genes were genotyped by a high throughput genotyping method, MALDI-TOF MS, to search for mutations related to eggshell ultrastructural properties.384pure-line Rhode Island White layers were selected for this study. As for the following4genes: Ovalbumin、Ovocleidin-116、Ovocalyxin-32and ChEST985k21. Associtations were found for: Ovalbujhhmin with eggshell thickness and effective layer thickness, Ovocleidin-116with mammillary layer thickness、effective layer thickness and the average size of mammillary cones, Ovocalyxin-32with eggshell thickness, ChEST985k21with eggshell thickness and mammillary layer thickness.更多还原