Analysed data for paper 'Genetic variation and potential for improvement of cuticle deposition on chicken eggs through selection'

Analysed data for paper 'Genetic variation and potential for improvement of cuticle deposition on chicken eggs through selection.'

ABSTRACT
Background: The cuticle is an invisible glycosylated protein layer that covers the outside of the eggshell, forming a barrier to the transmission of microorganisms. Cuticle-specific staining and in situ absorbance measurement have been used to quantify cuticle deposition in several pure breeds. For brown eggs, a pre-stain and a post-stain absorbance measurement was required to correct for intrinsic absorption by the natural pigment. For white eggs a post-stain measurement only was sufficient to estimate the cuticle genetic parameters.

Results: In all the pure breeds measured, Rhode Island Red, two White Leghorns, White Rock and broiler, cuticle deposition had moderate heritability with an overall estimate of 0.36. In the Rhode Island Red, the genetic correlation between a measurement made early in the egg laying period and later was near one. There was no negative correlation with production traits. There was heterogeneity in the genetic correlations between color and cuticle, varying from negative or none in brown-egg layers to positive in white- or tinted-egg layers.
The use of the intrinsic tryptophan fluorescence of the cuticle protein to quantify the amount of cuticle deposition was unsatisfactory because of complex quenching processes. Tryptophan fluorescence intensity at 330 nm was moderately heritable, but there was no evidence of any genetic correlation with cuticle deposition. This was complicated further by a negative correlation with color in brown eggs, due to quenching of tryptophan fluorescence by energy transfer to protoporphyrin pigment. We also confirmed that cuticle removal increased reflection of ultraviolet wavelengths from the egg.

Conclusions: These results reinforce that cuticle deposition can be incorporated into breeding programs of egg- and meat-type birds to reduce vertical and horizontal transmission of potentially pathogenic organisms and help to improve biosecurity in poultry.

Dunn, Ian "Analysed data for paper 'Genetic variation and potential for improvement of cuticle deposition on chicken eggs through selection'" (2018) Edinburgh DataVault DOI: 10.7488/0cb81910-40ee-49e8-b421-0c08b41985a8