Table 4.

Plasma LH, FSH, and E2 levels of laying hens at 22, 26, 30, 34, and 38 WOA exposed to different ammonia concentrations under 20°C and 35°C.

Item1	LH (pg/mL)	FSH (mIU/mL)	E2 (pg/mL)
T (°C)
20	53.89 ± 0.69a	8.34 ± 0.16a	94.64 ± 1.49a
35	45.48 ± 0.80b	7.68 ± 0.14b	81.95 ± 1.30b
AC (ppm)
≤5	51.99 ± 1.02a	8.55 ± 0.20a	99.32 ± 0.78a
20	49.88 ± 0.90a,b	7.87 ± 0.17b	86.64 ± 1.50b
45	47.19 ± 1.02b	7.61 ± 0.17b	78.92 ± 1.60c
WOA
22	49.37 ± 0.95b	7.80 ± 0.23	84.09 ± 1.74c
26	55.49 ± 0.96a	8.15 ± 0.22	85.08 ± 1.89b,c
30	49.62 ± 1.37b	7.63 ± 0.22	91.38 ± 2.29a,b
34	48.38 ± 1.37b,c	8.17 ± 0.23	93.53 ± 2.64a
38	45.58 ± 1.40c	8.31 ± 0.27	87.39 ± 2.76a,b,c
P-value2
T	<0.05	<0.05	<0.05
AC	<0.05	<0.05	<0.05
WOA	<0.05	NS	<0.05
T × AC	<0.05	<0.05	NS
T × WOA	<0.05	NS	<0.05
AC × WOA	<0.05	NS	NS

^a–cMeans within main effects without a common letter differ (P < 0.05).

Abbreviations: E2, estradiol; FSH, follicular stimulating hormone; LH, luteinizing hormone.

¹T, temperature; AC, ammonia concentration; WOA, week of age.

²NS, no significance.