Genotype‐Dependent Variations in Egg Quality and Nutritional Composition of Thermotolerant Chickens Under Hot‐Climate Conditions

Egg quality and nutritional composition may vary among thermotolerant chicken genotypes reared under hot-climate conditions, with potential implications for nutritional value and climate-resilient poultry production. This study compared egg morphometric traits, amino acid composition, yolk fatty acid profile, and mineral content in Fayoumi, Naked Neck, and Frizzled laying hens maintained under the same general feeding and management conditions during the summer period. Naked Neck hens produced the heaviest eggs (55.29 ± 4.11 g) compared with Frizzled (50.18 ± 3.71 g) and Fayoumi hens (48.92 ± 3.85 g), and also showed the highest albumen height (5.81 ± 0.14 mm) and Haugh unit (83.39 ± 1.55). Total protein content ranged from 12.80 ± 0.60 to 13.28 ± 0.11 g/100 g edible portion, whereas individual amino acids displayed clearer variation among genotypes. Fayoumi eggs showed the highest methionine concentration (320.40 ± 20.10 mg/100 g dry matter), Naked Neck eggs the highest leucine level (636.27 ± 82.93 mg/100 g dry matter), and Frizzled eggs the highest histidine content (211.55 ± 6.98 mg/100 g dry matter). Yolk lipid composition also differed among groups: Fayoumi eggs had the highest total lipid (8.92% ± 0.64%) and PUFA proportions (19.10% ± 0.95%), Naked Neck eggs showed the highest MUFA (49.61% ± 1.55%) and total ω3 contents (3.62% ± 0.16%), including the highest DHA level (1.26% ± 0.05%), whereas Frizzled eggs exhibited the lowest ω6/ω3 ratio (3.76 ± 1.48). Mineral composition was more conserved, with sodium, calcium, phosphorus, and potassium remaining comparable across genotypes, whereas iron content differed significantly and was highest in Naked Neck eggs (1.30 ± 0.19 mg/egg) compared with Fayoumi (1.24 ± 0.15 mg/egg) and Frizzled eggs (1.10 ± 0.08 mg/egg). The three genotypes exhibited distinct compositional profiles in the egg matrix, involving morphometric traits, amino acid distribution, lipid fractions, and iron deposition under the present experimental conditions.