Uterine transcriptome analysis reveals mRNA expression changes associated with the ultrastructure differences of eggshell in young and aged laying hens

Table 1 Comparison of chemical composition, physical and mechanical properties of eggshell between young (42 wk. of age) and aged hen groups (72 wk. of age)

Items	Young hen	Aged hen	P-value
Calcium content (mg/g)	370.62 ± 19.72	344.68 ± 33.96	0.083
Phosphorus content (μg/g)	1.11 ± 0.12	1.00 ± 0.17	0.169
Matrix protein content (mg/g)	13.72 ± 1.18	13.32 ± 1.18	0.507
Shell thickness (mm)	0.37 ± 0.02	0.39 ± 0.02	0.234
Egg weight (g)	64.42 ± 0.54	65.83 ± 1.12	0.006
Shell weight (g)	6.37 ± 0.05	6.49 ± 0.10	0.008
Shell ratio (%)	9.89 ± 0.05	9.86 ± 0.04	0.244
Breaking strength (N)	46.32 ± 1.64	36.85 ± 2.74	< 0.001
Stiffness (N/mm)	74.88 ± 1.91	75.39 ± 3.16	0.702
Elastic modules (N/mm²)	7636.34 ± 133.61	7583.75 ± 261.38	0.620
Fracture toughness (N/mm^3/2)	573.11 ± 40.29	456.35 ± 38.75	< 0.001

Data are the mean of 8 replicates with 24 eggs each (another 12 eggs of each replicate for the measurement of stiffness, elastic modules and fracture toughness)

ISSN: 1471-2164