Dual-Purpose Poultry in Organic Egg Production and Effects on Egg Quality Parameters

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Egg laying genotypes have been selected for generations due to their high yield and egg
quality, resulting in efficient feed utilization and low body weight; hence, they are not suitable for
meat production. This imposes an issue for the male layer chicks, which are killed at one day old.
Because of ethical and food waste concerns, the search for suitable dual-purpose genotypes in order
to avoid euthanasia of male day-old chicks has intensified. The aim of the present study is to evaluate
potential dual-purpose genotypes for their egg quality compared to a representative egg laying
genotype. Three dual-purpose genotypes with divergent characteristics were evaluated: genotype
A represented an experimental crossbreed based on a broiler type male and an egg layer female,
genotype B was a pure breed, and genotype C was a crossbreed of a layer type. These were compared
to a control genotype D, which was an egg layer. Eggs were collected six times during the period of
21–54 weeks of hen age, i.e., a total of 1080 shell eggs were analyzed. Examined parameters were
weights of egg, shell, yolk, and albumen, by calculating their relative proportions. Shell quality was
assessed by shell strength, shell stiffness, and shell thickness. Yolk quality was determined as yolk
color and inclusions of blood and meat spots, and albumen quality was evaluated in terms of pH and
dry matter (DM) content. The egg layer genotype produced the smallest eggs with least blood and
meat spot inclusions compared to that produced by the three dual-purpose genotypes. Shell quality
was superior for the layer genotype. However, the experimental genotype A laid eggs of comparable
shell quality, albumen DM, and yolk weight, but also with the darkest and most red-yellow colored
yolk. The two other dual-purpose genotypes produced eggs of low-medium quality. In conclusion,
the genotype A could serve as dual-purpose genotype from an egg quality perspective.
Original languageEnglish
Article number897
Number of pages16
Publication statusPublished - Apr 2021

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