Table 8.

Effects of dietary manganese (Mn) supplementation on serum hormones of duck breeders at the end of the trial (34 wk).

Variables	Mn supplemental level (mg/kg)1						SEM	P-value
	0	20	40	80	120	160		ANOVA	Linear	Quadratic
Estradiol (ng/L)	436	529	501	522	470	421	7.7	<0.001	0.037	<0.001
Luteinizing hormone (ng/L)	455	559	556	566	549	494	8.0	<0.001	0.685	<0.001
Follicle-stimulating hormone (IU/L)	8.76	10.1	10.4	10.1	10.3	7.80	0.18	<0.001	0.061	<0.001
Prolactin (ng/L)	389	382	396	382	376	368	2.7	0.041	0.005	0.013
Progesterone (pmol/L)	1,731	1,780	1,798	1,887	2,007	2,254	35.7	<0.001	<0.001	<0.001

¹Mean of 6 replicates (2 ducks per replicate) per treatment.