Table 8. Plasma urea nitrogen concentration, serum estradiol-17β concentration and serum progesterone concentrations at 29 week of age in broiler breeder hens fed gradient lysine levels¹⁾

Total lysine (%)	Daily lysine intake (mg/d)	Plasma urea nitrogen (mg/dL)	Serum P4 (ng/mL)	Serum E2 (pg/mL)
0.55	732	0.32	0.26	330.6
0.59	785	0.44	0.09	347.8
0.63	838	0.33	0.38	345.7
0.67	891	0.38	0.14	389.9
0.71	944	0.51	0.81	433.6
0.75	998	0.46	0.08	405.1
0.79	1,051	0.47	0.17	353.4
SEM		0.022	0.063	16.08
p-value		0.114	0.192	0.607

Results are the mean of 6 replicates per treatment.
P4, progesterone; E2, estradiol-17β; SEM, standard error of the mean.