番鸭蛋壳通透性及其对出雏效果的影响

将同批入孵番鸭种蛋分为6组:新鲜种蛋,一照时的健胚蛋、死胚蛋,三照死胚蛋,正常出雏蛋,毛蛋(啄壳时死胚蛋),分别测定各组种蛋大端、中部和小端的气孔数、厚度及蛋壳结构,并研究它们对出雏的影响.结果表明:一照、三照死胚蛋和毛蛋的气孔数(52.28、55.32和71.60个·cm-2)极显著少于一照健胚蛋(83.60个·cm-2)和正常出雏蛋(86.28个·cm-2);而在蛋壳厚度上,三照死胚蛋(0.401mm)和毛蛋(0.395mm)均极显著高于正常出雏蛋(0.363mm).采用扫描电镜观测新鲜种蛋、毛蛋和正常出雏蛋蛋壳结构.结果显示,新鲜种蛋壳由壳膜、乳锥层、柱状层、垂直晶体层和油质层构成,正常出雏蛋及毛蛋的乳锥层因胚胎发育对矿物质的吸收利用造成部分缺失;死胚蛋蛋壳厚度(0.395-0.401mm)极显著高于正常出雏蛋(0.363mm).可见蛋壳过厚、气孔较少是影响番鸭蛋孵化后期气体交换,导致死胚的重要原因.

Effects of eggshell conductivity of hatching eggs of muscovy duck on the hatchability

Divided into six groups, normal eggs, the first candling normal eggs, the first and third candling addled eggs, the pipped eggs and the eggs hatched normally, muscovy duck's hatching eggs were hatched at the same time. In order to find out these factors' effect on the hatchability, the pore number and thickness and structure of big end, middle part and the small end, the thickness and the structure of each group were determined. The results indicated that the average pore number(52.28, 55.32, 71.60 entries·cm-2) of the first and third candling addled eggs and the pipped eggs was significantly less than that of the candling normal eggs (83.60 entries·cm-2) and that of the normally hatched eggs (86.28 entries·cm-2). In the aspect of thickness, the third candling addled eggs' (0.401 mm) and the pipped eggs' (0.395 mm) were all significantly higher than that of the normally hatched eggs' (0.363 mm). To reveal the structure of muscovy duck's eggshell, we observed the eggshell of the normal eggs, the pipped eggs and the normally hatched eggs with scanning electron microscope. We found out that the eggshell of normal eggs consists of shell membrane, mammillary cone layer, palisade layer, vertical crystal layer and cuticle. The mammillary cone layer of the pipped eggs and the normally hatched eggs is partly lost by assimilating mineral in fetation. Also it proved that the thickness of pipped eggs (0.395-0.401 mm) is significantly higher than that of the eggs hatched normally (0.363 mm). Excessive thickness is the main cause that affects the exchange of air and results in addled eggs in hatching anaphase.