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Despite the wide biodiversity of avian species of zootechnical interest in Spain, projects aimed at characterizing these genotypes and their products are necessary. External and internal egg quality traits were measured in 819 eggs laid by hens of 10 different genotypes: White, Franciscan, Black and Partridge varieties of Utrerana, Blue Andalusian, Spanish White-Faced, Andalusian Tufted White and Black varieties, Araucana; and Leghorn Lohmann LSL-Classic lineage (commercial hybrid line) hen breeds. After multicollinearity analysis of egg quality-related traits was performed (VIF ≤ 4), major diameter, minor diameter, egg weight, and albumen height were deemed redundant explanatory variables and discarded. A stepwise discriminant canonical analysis was developed to cluster eggs across hen genotypes considering egg quality attributes. Shell a* and b* variables reported the highest discriminant power (Wilks' lambda: 0.699 and 0.729, respectively). The first two discriminant functions captured 60.48% of the variance across groups (F1: 39.36%; F2: 21.12%). Clear quality differentiation signs are evidenced for Mediterranean native breeds' eggs when compared to Leghorn's eggs. Consequently, this evidence of egg quality differentiation may favor the standardization of breed- and variety-linked distinctive products, which may open new market opportunities based on the existence of a wide spectrum of diet or culinary applications. [ABSTRACT FROM AUTHOR]

This study aimed to develop a tool to validate multivariety breed egg quality classification depending on quality-related internal and external traits using a discriminant canonical analysis approach. A flock of 60 Utrerana hens (Franciscan, White, Black, and Partridge) and a control group of 10 Leghorn hens were placed in individual cages to follow the traceability of the eggs and perform an individual internal and external quality assessment. Egg groups were determined depending on their commercial size (S, M, L, and XL), laying hen breed, and variety. Egg weight, major diameter, minor diameter, shell b*, albumen height, and the presence or absence of visual defects in yolk and/or albumen showed multicollinearity problems (variance inflation factor (VIF) > 5) and were discarded. Albumen weight, eggshell weight, and yolk weight were the most responsible traits for the differences among egg quality categories (Wilks' lambda: 0.335, 0.539, and 0.566 for albumen weight, eggshell weight, and yolk weight, respectively). The combination of traits in the first two dimensions explained 55.02% and 20.62% variability among groups, respectively. Shared properties between Partridge and Franciscan varieties may stem from their eggs presenting heavier yolks and slightly lower weights, while White Utrerana and Leghorn hens' similarities may be ascribed to hybridization reminiscences. [ABSTRACT FROM AUTHOR]

Simple Summary: The development of new more productive lines of laying hens has displaced native breeds to second place; therefore, new lines of research that ensure the conservation of local breeds and biodiversity are increasingly necessary. The aim of the present study is to characterize the productive capability of Utrerana and to compare the relationships among parameters determining the internal and external quality of the egg, through canonical correlation analysis. We used a flock of 68 Utrerana hens with animals of each of its four varieties (white, black, Franciscan and partridge), and a group of 17 Leghorn hens as a control group. The breed and variety significantly affected egg characteristics. The external and internal quality parameters of the egg were evaluated and reported results providing consistent data for the characterization of the products from this breed. This productive characterization could benefit the conservation of the Utrerana breed, the establishment of livestock models that adapt to it and the search for a market in which this product could be used. The aim of the present study is to characterize the productive capability of Utrerana and to compare the relationships among parameters determining the internal and external quality of the egg, through canonical correlation analysis. A flock of 68 Utrerana hens and a control group of Leghorn hens (n = 17) were housed individually to allow individual identification of eggs and for the assessment of egg quality characteristics. Almost all variables showed differences when both breeds were compared, except for white height, yolk diameter, yolkL* and yolk pH (p > 0.05). Only minor diameter, white height, yolkL*, yolka*, and shell weight reported significant differences between laying age groups. White height, yolk color, and almost all yolk color coordinates were significantly different (p < 0.05) for period and month. Egg and white weight reached highest significantly different levels for the fourth and fifth time that the hens laid an egg. External quality-related traits are better predictors of internal quality-related traits than vice versa, enabling the implementation of an effective noninvasive method for internal quality determination and egg classification aimed at suiting the needs of consumers. [ABSTRACT FROM AUTHOR]

• Protein, certain MUFA or total PUFA differences depend on hen breed and variety. • Fatty acid profile depends on breed, but only C18:2 n6 differs across varieties. • Hen breed conditions Ca, Cu, Fe, K, Mg, Mn, Na, Ni, P, Pb, S and Zn egg levels. • Black Utrerana and Leghorns reported higher linoleic acid contents. Eggshell, white and yolk chemical composition was compared across Utrerana breed varieties (black, partridge and franciscan) and Leghorn Lohmann LSL-Classic lineage. An Utrerana hens flock (n = 51) and a control group of Leghorn hens (n = 17) were housed individually allowing egg identification and quality characteristics assessment. Eggshell, yolk and white macroelements and microelements, carbohydrates, moisture, ashes, protein, fat (polyunsaturated and saturated), sugars, cholesterol, and α-tocopherol contents were analyzed. Simultaneously, itemized yolk fatty acids composition was evaluated. Calcium contents were higher in Utrerana eggshell (358.53 g/kg vs. 337.01 g/kg) and white (593.75 mg/kg vs. 584.31 mg/kg), while protein contents were higher in Utrerana yolk (17.40 % vs. 16.90 %) and white (10.60 % vs 10.30 %). Utrerana yolks reported higher α-tocopherol (102.00 mg vs. 88.00 mg), total polyunsaturated fatty acids (19.80 % vs. 16.60 %), and some monounsaturated fatty acids content (C18:1 n9: 42.68 % vs. 41.31 % ; C16:1 n9: 0.60 % vs. 0.50 %). Black variety and Leghorns reported higher linoleic acid contents (13.72 % and 13.27 %, respectively) than the rest of the Utrerana varieties. Conclusively, detailed knowledge on differentiated properties of eggs depending on the animals originating them enables a correctly approaching market needs to improve the profitability and find a competitive niche for local products. [ABSTRACT FROM AUTHOR]