Animal Science, School of Environmental and Rural Science, Woolshed Building (W49), University of New England, Armidale, New South Wales, 2351, Australia.
Poult Sci. 2013 Oct;92(10):2783-8. doi: 10.3382/ps.2013-03051.
Protoporphyrin has been identified as the main eggshell pigment in brown-shelled eggs. However, there has been some uncertainty concerning the distribution of the pigment within the shell (and cuticle) in brown-shelled eggs. Most previous studies have suggested that the bulk of the shell pigment is deposited in the cuticle of the shell. The present study measured the levels of protoporphyrin in intact eggshells and in shells from which the cuticle had been removed, using eggs from flocks at 3 different ages. This enabled the calculation of the relative amount of protoporphyrin in the calcareous eggshell and the cuticle layer of the eggshell. The majority of the protoporphyrin pigment was located in the calcareous part of the eggshell (80-87%) with a minority contained within the cuticle (13-20%). These findings suggest that studies focused on maintenance of shell color in brown-shelled eggs need to consider the stage of egg formation at which the reduction in pigment deposition is occurring.
原卟啉已被确定为棕色蛋壳蛋的主要蛋壳色素。然而，关于棕色蛋壳中色素在壳（和角质层）内的分布存在一些不确定性。大多数先前的研究表明，大部分壳色素沉积在壳的角质层中。本研究使用来自 3 个不同年龄鸡群的鸡蛋，测量了完整蛋壳和去除角质层后的蛋壳中卟啉的水平。这使得可以计算出蛋壳的钙质部分和蛋壳角质层中卟啉的相对含量。大部分原卟啉色素位于蛋壳的钙质部分（80-87%），一小部分位于角质层内（13-20%）。这些发现表明，研究集中在维持棕色壳蛋的壳色方面，需要考虑色素沉积减少发生的鸡蛋形成阶段。
