. 2020 Mar 31;10(4):584. doi: 10.3390/ani10040584

Table 3.

Effect of age on yolk, albumen, shell percentage and yolk to albumen ratio according to the genotype of the hens.

	Genotypes ¹
	ER	RM	HB	HW
Yolk, %
31 weeks	27.9 ^Cc	26.6 ^Cc	23.4 ^Bb	24.5 ^Bb
35 weeks	29.8 ^Bb	28.6 ^AaBb	24.4 ^AaB	26.6 ^Aa
39 weeks	30.1 ^Bb	28.5 ^Bb	25.3 ^Aa	26.6 ^Aa
43 weeks	31.6 ^Aa	29.7 ^Aa	25.2 ^Aa	27.1 ^Aa
RMSE	1.76	1.47	1.50	1.46
Component p-value	linear <0.0001	linear <0.0001	linear <0.0001	linear <0.0001
Albumen, %
31 weeks	62.1 ^Aa	62.4	65.2	65.2 ^Aa
35 weeks	60.4 ^Bb	60.7	64.9	63.4 ^Bb
39 weeks	59.4 ^Bbc	59.9	64.2	62.6 ^Bb
43 weeks	58.8 ^Bc	58.9	64.3	62.6 ^Bb
RMSE	2.07	1.61	1.66	1.61
Component p-value	linear <0.0001	linear <0.0001	linear 0.0118	linear <0.0001
Eggshell, %
31 weeks	10.0 ^Aa	11.0 ^ab	11.4 ^Aa	10.3 ^ABb
35 weeks	9.8 ^Bb	10.7 ^b	10.7 ^Bb	10.0 ^Bb
39 weeks	10.5 ^Aa	11.6 ^a	10.5 ^Bb	10.8 ^Aa
43 weeks	9.5 ^Bb	11.3 ^ab	10.5 ^Bb	10.3 ^AaBb
RMSE	0.86	0.91	0.90	0.75
Component p-value	cubic 0.0004	cubic 0.0105	linear <0.0001	cubic <0.0001
Yolk to albumen ratio
31 weeks	0.452 ^Cc	0.430 ^Cc	0.361 ^Bb	0.377 ^Bb
35 weeks	0.497 ^Bb	0.476 ^Bb	0.378 ^AaBb	0.422 ^Aa
39 weeks	0.512 ^AaBb	0.482 ^Bb	0.397 ^Aa	0.427 ^Aa
43 weeks	0.541 ^Aa	0.512 ^Aa	0.394 ^Aa	0.436 ^Aa
RMSE	0.0476	0.0368	0.0326	0.0339
Component p-value	linear <0.0001	linear <0.0001	linear <0.0001	linear <0.0001

Different letters among rows of each genotype indicate different values. a, b, c: p < 0.05; A, B, C: p < 0.01. RMSE = Root Mean Squared Error. Only the component with the highest and significant p-value is shown. ¹ Genotypes: ER—Ermellinata di Rovigo; RM—Robusta maculata; HB—Hy Line Brown; HW—Hy Line White 36. Observations (n) per age (at 31, 35, 39, 43 weeks): ER (30, 32, 25, 27); RM (25, 15, 30, 29); HB (30, 30, 30, 30); HW (30, 35, 30, 28).