Age-related changes in the shell gland and duodenum in relation to shell quality and bone strength in commercial laying hen hybrids

Table 1 Body weight, oviduct length, breaking strength of femur, breaking strength of humerus and total calcium in plasma of two layer hybrids

	LSL and LB						Statistical significance (P value)
	21 weeks (n = 10)	29 weeks (n = 10)	49 weeks (n = 10)	70 weeks (n = 10)	LB (n = 20)	LSL (n = 20)	Age	Hybrid	Age* Hybrid
Body weight (g)	1661 ± 56.7^c	1726 ± 80.4^bc	1985 ± 123.2^a	1898 ± 107.1^ab	2037 ± 62.2^a	1598 ± 37.9^b	0.002	< 0.0001	0.2
Oviduct length (cm)^d	54 ± 0.8^b	56 ± 0.8^b	62 ± 1.2^a	63 ± 1.5^a	60 ± 1.2	58 ± 1.2	< 0.0001	0.2	0.6
Breaking strength, femur (N)^e	218 ± 10.4^a	168 ± 9.7^bc	137 ± 10.5^b	182 ± 9.7^ac	162 ± 9.1	191 ± 9.1	0.0001	0.07	0.04
Breaking strength, humerus (N)^e	252 ± 10.3^a	237 ± 9.7^ab	198 ± 10.4^b	225 ± 9.6^ab	235 ± 9.0	220 ± 9.0	0.02	0.3	0.1
Total calcium (mmol/L)	5.5 ± 0.14^b	6.1 ± 0.24^ab	6.5 ± 0.43^ab	7.0 ± 0.42^a	6.0 ± 0.25	6.6. ± 0.26	0.02	0.1	0.1

Lohmann Selected Leghorn (LSL) and Lohmann Brown (LB) at four different ages (21, 29, 49, 70 weeks) during the production period. Mean ± standard error. Values without a superscript or with the same letter (^a, ^b or ^c) do not differ significantly (P > 0.05)
^dMeasured from the orifice to the fimbriated infundibulum
^eMeasured by three-point bending, load (Newton) at failure; body weight included as a covariate in the analysis

ISSN: 1751-0147