Table 3.

Effects of dietary supplementation with essential oil on laying performance of laying hens¹

Items	Treatments2				SEM3	P-value
	Control	EO100	EO200	EO400		ANOVA	Linear	Quadratic
Egg production
weeks 1–4	0.880	0.905	0.907	0.905	0.0055	0.243	0.174	0.138
weeks 5–8	0.863	0.898	0.894	0.893	0.0064	0.183	0.197	0.134
weeks 9–12	0.854	0.861	0.885	0.861	0.0060	0.282	0.598	0.233
weeks 1–12	0.865	0.888	0.896	0.888	0.0050	0.144	0.163	0.064
Average egg weight, g
weeks 1–4	60.51	60.27	61.13	61.85	0.27	0.147	0.031	0.092
weeks 5–8	60.65	60.24	61.31	62.03	0.26	0.079	0.017	0.052
weeks 9–12	60.47	60.08	60.99	61.36	0.24	0.240	0.083	0.216
weeks 1–12	60.55	60.19	61.14	61.75	0.24	0.110	0.028	0.083
Average daily feed intake, g/hen per day
weeks 1–4	111.66	111.28	108.77	111.97	0.68	0.331	0.948	0.304
weeks 5–8	109.47	110.97	108.64	111.02	0.66	0.524	0.592	0.768
weeks 9–12	108.30	109.72	110.57	110.74	0.72	0.631	0.244	0.415
weeks 1–12	110.33	110.26	108.68	111.08	0.54	0.467	0.683	0.411
Feed conversion ratio, g/g
weeks 1–4	2.10	2.05	1.96	2.00	0.021	0.075	0.064	0.039
weeks 5–8	2.10	2.06	1.99	2.01	0.018	0.236	0.053	0.050
weeks 9–12	2.12a	2.10a	2.01b	2.09ab	0.015	0.029	0.272	0.048
weeks 1–12	2.11a	2.07ab	1.98b	2.03ab	0.016	0.026	0.053	0.017

¹ n = 8 replicates per treatment

² Control, hens received a basal diet; EO100, EO200 and EO400, hens received a basal diet supplemented with 100, 200 or 400 mg/kg oregano essential oil, respectively

³ SEM, standard error of the mean

^a-b Values within a row with no common superscripts differ significantly (P < 0.05)