Genetic parameters of the thick-to-thin albumen ratio and egg compositional traits in layer-type chickens

ABSTRACT

1. Generating a robust egg albumen is one of the major factors contributing to interior egg quality owing to its nutritive value and superior appearance. However, the genetic factors regulating the proportion of thick albumen are poorly understood.

2. In this study, 1330 eggs were collected from 450 Rhode Island White layers, aged 40 weeks, to measure egg compositional traits for three successive days. The restricted maximum likelihood method was applied to estimate genetic parameters for the thick-to-thin albumen ratio and other egg compositional traits. A univariate animal model was fitted to calculate heritability for each trait.

3. The heritabilities of egg weight, yolk weight, albumen height, Haugh units, percentages of yolk, thick albumen, thin albumen and the thick-to-thin albumen ratio were 0.32, 0.34, 0.28, 0.47, 0.61, 0.39, 0.31, and 0.45, respectively. The percentage of thick albumen was negatively correlated genetically with all traits, and percentage of thin albumen was negatively correlated genetically with all traits except for Haugh units. The thick-to-thin albumen ratio was positively correlated genetically with egg weight, albumen height and Haugh units, with correlations ranging from 0.21 to 0.54.

4. The results indicated that the percentage of thick albumen and the thick-to-thin albumen ratio were found to be moderately to highly heritable, and selection for the thick-to-thin albumen ratio could be conducive to the improvement of egg albumen quality.

KEYWORDS:

• Chicken
• egg quality
• genetic correlation
• heritability
• thick albumen

Acknowledgments

The authors are grateful to Dr. Longchao Zhang at the Chinese Academy of Agricultural Sciences for valuable comments on the manuscript. This work was supported in part by grants from the China Agriculture Research System (CARS-41-G18), the Major Science and Technology Project of Anhui Province (17030701006) and the Special Fund Projects for Innovation-driven Development of Guangxi Province (AA17204027).

Disclosure statement

No potential conflict of interest was reported by the authors.

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Additional information

Funding

This work was supported by the The China Agriculture Research System [CARS-41-G18]; The Special Fund Projects for Innovation-Driven Development of Guangxi Province [AA17204027]; The Major Science and Technology Project of Anhui Province [17030701006].