Quality, Chemical Composition, and Amino Acids of Eggs in Lohmann Pink-Shell Laying Hens and Dongxiang Green-Shell Laying Hens.

Hen breed and age are key factors influencing egg quality. In this study, 250 eggs were categorised into five groups: Lohmann Pink-shell (LMP, 50 ± 2 weeks), Dongxiang Green-shell (DXG, 50 ± 2 weeks), Dongxiang Pink-shell (DXP, 50 ± 2 weeks), first-laid Dongxiang Green-shell (DXGF, 23 ± 1 week), and first-laid Dongxiang Pink-shell (DXPF, 23 ± 1 week). We compared egg quality traits, biochemical parameters, chemical composition, and amino acid profiles across these groups. Average egg weights were 59.89 g (LMP), 52.11 g (DXG), 59.45 g (DXP), 42.01 g (DXGF), and 42.56 g (DXPF). Yolk colour scores were higher in DXGF (13.72) than in LMP, DXG, and DXP (12.93, 12.72, and 12.81, respectively; p < 0.05). Egg yolk high-density lipoprotein (HDL) levels were lower in LMP, DXG, and DXP (0.0316, 0.0390, and 0.0334 mmol/g, respectively) than in DXGF and DXPF (0.0411 and 0.0424 mmol/g; p < 0.05). Yolk crude fat was higher in DXG, DXP, DXGF, and DXPF (50.00%, 49.29%, 49.54%, and 49.93%, respectively) than in LMP (47.70%; p < 0.05). The EAA/TAA ratios in yolk ranged from 54.53 to 55.33, while those in albumen ranged from 53.38 to 53.71. Overall, this study demonstrates that hen breed and age significantly affect egg quality, biochemical traits, and amino acid composition. These findings may guide consumer egg selection and support the conservation and efficient utilization of chicken genetic resources.