不同家禽蛋壳结构及其成分研究

Shell Structure and Composition of Poultry Eggs

【目的】通过对不同家禽蛋壳结构及成分的比较研究,丰富人们对于鹅蛋蛋壳结构和成分的认识。【方法】选取江南白鹅、如皋黄鸡和金定鸭所产蛋各30枚,测定蛋壳强度、厚度;取蛋壳内表面、外表面及禽蛋尖端、赤道以及钝端的横断面蛋壳碎片固定在铜板上,喷金,在扫描电镜合适倍数视野下观察蛋壳的超微结构。【结果】蛋重、蛋壳重以及蛋壳厚度在鸡蛋、鸭蛋和鹅蛋之间均差异显著(P<0.05),表现为鹅蛋>鸭蛋>鸡蛋;而鹅蛋蛋壳强度、蛋形指数和壳重比例显著高于鸡蛋和鸭蛋(P<0.05)。鹅蛋蛋壳栅栏层的厚度与所占比例均显著大于鸡蛋和鸭蛋(P<0.05),鹅蛋蛋壳的横断面致密度和平整性都更好,乳突层与壳膜层联系也更加紧密;蛋壳强度与有效层厚度的相关性最强,其相关系数为0.603;3种禽蛋蛋壳中碳、氧、钙、锌的相对含量均没有显著差异(P>0.05),相对含量最高的元素均为:氧、钙、碳,说明蛋壳中无机物质主要是碳酸钙,且蛋壳质量并不取决于元素相对含量的高低。【结论】鹅蛋在蛋壳强度、蛋壳厚度以及蛋壳结构等方面与鸡蛋、鸭蛋有显著差异,蛋壳强度并不取决于元素相对含量的高低,受蛋壳微观结构的影响更大,蛋壳的致密度直接影响了蛋壳强度。

【Objective】Shell structure and composition of eggs laid by different kinds of poultry were compared.【Method】Thirty eggs of Jiangnan white geese,Rugao yellow chickens,and Jinding ducks were examined for microstructures of the inner/outer surfaces and cross-sections of fragments from various parts under a scanning electron microscope,determined on the physical properties using a strength tester,measured for the thickness with a spiral micrometer,and analyzed on the chemical composition by standard methods.【Result】The egg weight,shell weight,and shell thickness of different species of poultry differed significantly(P<0.05)with a ranking of goose eggs>duck eggs>chicken eggs.The shell strength,shape index,and weight ratio of the goose eggs were significantly higher than those of the chicken or duck eggs(P<0.05).Both thickness and proportion of palisade layer of goose eggshell were significantly greater than those of chicken or duck eggshell(P<0.05).The transverse section density and integrality of goose eggshells were better and the mastoid layer more closely related to the shell layer,while the shell strength highly correlated with the effective layer thickness showing a correlation coefficient of 0.603.The relative contents of carbon,oxygen,calcium,and zinc in the eggshells did not differ significantly(P>0.05),and oxygen,calcium,and carbon were the greatest amount of inorganic substance and present mainly in the form of calcium carbonate.Thus,the eggshell quality did not depend on the relative content of these elements.【Conclusion】Goose eggs are significantly different from chicken eggs and duck eggs in terms of shell strength,shell thickness and shell structure.The eggshell strength does not depend on the relative content of the elements,but is more affected by the ultrastructure of the eggshell,and the density of the eggshell directly affects the eggshell strength.