Table 2.
Effect of hen genotype, A, B, C, and D, age, and their interaction on LS-means of egg shell parameters between the 21st and 54th week of age, n = 180 for genotype A and 270 for genotypes B, C and D.
| Genotype (G) | A | B | C | D | Effect of | SEM | ||
|---|---|---|---|---|---|---|---|---|
| G | Age | G * Age | ||||||
| Shell strength at fracture, N |
47.2 b | 38.3 d | 42.7 c | 50.6 a | *** | *** | NS | 0.423 |
| Shell-to-egg compression,% | 1.014 a | 0.951 c | 0.953 c | 0.984 b | *** | *** | NS | 0.007 |
| Shell stiffness, N/mm NB | 75.8 b | 73.4 b | 75.4 b | 82.0 a | *** | *** | NS | 0.928 |
| Shell thickness, mm | 0.438 b | 0.403 d | 0.415 c | 0.444 a | *** | *** | * | 0.002 |
| Shell weight, g | 6.0 a | 5.5 c | 5.7 b | 6.0 a | *** | *** | ** | 0.031 |
| Shell, % (w/w) | 9.9 b | 8.9 d | 9.4 c | 10.1 a | *** | *** | * | 0.043 |
a–d values of same parameter with different letter superscript are significantly different at * (p < 0.05), ** (p < 0.01) or *** (p < 0.001). NS = non-significant. NB: data analysis was performed on log-transformed data. SEM = standard error of mean.