Changes in muscle cell cation regulation and meat quality traits are associated with genetic selection for high body weight and meat yield in broiler chickens

Table 2 Intraclass correlations for breast muscle composition and Na, Ca, Mg and K ion concentrations of breast muscle samples and plasma for 34 genetic lines of chickens calculated over all genetic lines (t_w) and within category (t_wb)

Trait	Intraclass correlation¹		Category average			SED²
	t_w	t_wb	Broiler	Layer	Traditional
Breast muscle composition g/kg
Water	0.00	0.00	742	746	746	2.6
Organic matter	0.02	0.00	246	240	239	2.6*
Inorganic matter	0.14	0.00	12	14	15	0.5***
Element concentration μg/mg breast muscle ash
Na	0.39^‡	0.10	53.3	36.8	38.2	2.65***
K	0.25^†	0.17	245	208	205	13.3**
Mg	0.22^†	0.10	23.9	19.7	20.0	1.14***
Ca	0.24^†	0.15	4.08	3.07	3.48	0.292**
Element concentration μg/mg breast muscle DM
Na	0.24^†	0.11	2.51	2.05	2.12	0.116***
K	0.08	0.09	11.6	11.4	11.2	0.44
Mg	0.18	0.18	1.14	1.08	1.10	0.041
Ca	0.09	0.07	0.194	0.172	0.185	0.0113
Plasma ion concentration mmol/L
Na⁺	0.68^§	0.28^†	149.5	144.3	144.1	0.655***
K⁺	0.28†	0.04	4.44	3.67	3.81	0.129***
Mg²⁺	0.26†	0.14	0.979	0.963	0.853	0.0323***
Total Ca²⁺	0.63^§	0.50^‡	3.16	2.53	2.56	0.058***
Free Ca²⁺	0.33^‡	0.28^†	1.89	1.71	1.72	0.071*
Free/Total Ca²⁺	0.34^‡	0.27^†	0.60	0.68	0.68	0.029**

The means for broiler, layer and traditional lines of chickens are also presented
¹Significance of between line (breed) variance component (t-test): † p < 0.05; ‡ p < 0.01; § p < 0.001
²Standard error of a difference between two category means: ** p < 0.05; *** p < 0.001

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