Correlations between organic matrix and eggshell properties of 3 kinds of eggshells in Muscovy duck (Cairina moschata)

In order to analyze the relationship between organic matrix and eggshell properties in Muscovy duck eggshells with different qualities, the organic matrices in the eggshells of normal, pimpled, and striped eggs of white-feathered Muscovy ducks were extracted and separated into acid-insoluble, water-insoluble, and facultative-soluble matrix (both acid- and water-soluble). There was no significant difference in calcified shell thickness between normal and pimpled eggs. However, the percentages of acid-insoluble matrix and total matrix were significantly higher, and the breaking strength was significantly lower in pimpled eggs than those in normal eggs. In striped eggs, the percentages of acid-insoluble matrix, facultative-soluble matrix, and total matrix, calcified shell weight, calcified shell thickness, and breaking strength were significantly lower than those in normal eggs. The amount and percentage of 3 organic matrices (water-insoluble matrix, facultative-soluble matrix, and total matrix) were significantly positively correlated with calcified shell thickness in normal eggs rather than striped and pimpled eggs. Our results also demonstrated that there was no linear correlation between the organic components in the 3 Muscovy duck eggshells and the mechanical properties of the eggshells. The lower breaking strength of pimpled eggshells might be due to the unbalanced enrichment of certain proteins, whereas the striped eggs might mainly result from thinner calcified shells and poor balance between different sedimentary layers.