Table 1. Descriptive statistics of the measured phenotypes in the F₂ chicken population

Trait	Type	unit	Mean	SD	CV (%)	Min	Max	Trans
Alanine	Nonessential	µmol/g	1.5772	0.7439	0.4716	0.032	5.139	Sqrt
Arginine	Essential	µmol/g	9.0896	5.9595	0.6556	0.059	42.62	Sqrt
Asparagine	Nonessential	µmol/g	0.2946	0.158	0.5363	0	0.834	Sqrt
Aspartic acid	Nonessential	µmol/g	0.4188	0.2583	0.6169	0.012	1.93	Sqrt
Cysteine	Nonessential	µmol/g	3.4547	1.9151	0.5544	0.09	12.61	Sqrt
GABA	Nonessential	µmol/g	0.0564	0.0632	1.1207	0	0.68	Sqrt
Glutamic acid	Nonessential	µmol/g	1.2466	0.661	0.5302	0.031	9.389	Sqrt
Glutamine	Nonessential	µmol/g	1.1161	0.6518	0.584	0.02	5.257	Sqrt
Glycine	Nonessential	µmol/g	0.8388	0.5757	0.6863	0.01	4.91	Sqrt
Histidine	Essential	µmol/g	0.34	0.1819	0.5349	0.01	1.07	Sqrt
Isoleucine	Essential	µmol/g	0.3973	0.1789	0.4503	0.008	1.12	Min-Max
Leucine	Essential	µmol/g	0.8782	0.4067	0.4631	0.019	2.38	No trans
Lysine	Essential	µmol/g	0.0299	0.1128	3.7769	0	1.44	Sqrt
Methionine	Essential	µmol/g	0.6394	0.5242	0.8198	0.013	4.169	Log
Phenylalanine	Essential	µmol/g	0.4195	0.1998	0.4762	0.006	1.58	Min-Max
Proline	Nonessential	µmol/g	0.3564	0.2792	0.7834	0.004	6.29	Sqrt
Serine	Nonessential	µmol/g	1.342	0.5624	0.419	0.039	3.26	Min-Max
Threonine	Essential	µmol/g	0.8727	0.4369	0.5006	0.014	3.007	Sqrt
Tryptophan	Essential	µmol/g	0.0343	0.0376	1.0964	0	0.89	Sqrt
Tyrosine	Nonessential	µmol/g	0.6248	0.5362	0.8582	0.019	2.97	Log
Valine	Essential	µmol/g	0.3802	0.2194	0.5771	0.002	1.707	Sqrt
Essential FAAs		µmol/g	15.2358	7.4925	0.4918	0.32	52.59	Sqrt
Nonessential FAAs		µmol/g	9.108	3.7094	0.4073	0.74	25.98	Sqrt
AMP	NT	mg/100g	10.2654	4.4131	0.4299	0.03	30.61	Sqrt
IMP	NT	mg/100g	297.7067	86.4317	0.2903	24.4	572.61	No trans
Inosine	NT	mg/100g	49.8131	20.7431	0.4164	4.6749	146.47	Sqrt
Hypoxanthine	NT	mg/100g	15.7305	5.7408	0.3649	4.74	42.52	Log

CV, coefficient of variation; Min, minimum; Max, maximum; Trans, transformation; Sqrt, square root scaling; GABA, γ-aminobutyric acid; Min-Max, minimum-maximum scaling; Log, Log scaling; FAA, free amino acid content; AMP, adenosine monophosphate; NT, nucleotide content; IMP, inosine 5’-monophosphate.