Table 2.

Mean daily weight gain (DWG), daily feed intake (DFI), feed conversation ratio (FCR), and European economic efficiency index (EEEI) in broiler chickens that received Satureja khuzistanica essential oils (SkEO) by gavage method and acetic acid (AA) in days 14 to 42 of age.

SkEO (mg/bird/day)	AA (g/kg)	DWG	DFI	FCR	EEEI
0		53.71	105.40	2.00	185
200		60.77	111.84	1.85	230
300		59.28	110.13	1.88	224
400		57.10	106.79	1.89	211
500		56.95	106.16	1.87	209
600		56.75	104.44	1.84	212
SEM		2.42	3.17	0.04	16.00
	0	60.54a	111.13a	1.84b	232a
	20	54.32b	103.79b	1.93a	192b
SEM		1.39	1.88	0.02	9.23
0	0	56.81	108.35	1.90	211
0	2	57.68	104.50	1.84	189
200	0	60.67	111.10	1.86	230
200	2	58.23	107.50	1.90	218
300	0	58.95	110.10	1.87	226
300	2	58.71	107.40	1.79	217
400	0	58.70	108.50	1.85	225
400	2	56.50	104.50	1.85	210
500	0	58.28	108.10	1.86	223
500	2	55.30	104.70	1.91	201
600	0	58.65	108.25	1.84	222
600	2	55.15	104.65	1.87	203
SEM		2.10	2.10	0.04	14.50
		P-values
SkEO		0.426	0.515	0.264	0.459
AA		0.002	0.005	0.025	0.004
SkEO × AA		0.621	0.583	0.675	0.681
Linear		0.938	0.339	0.090	0.674
Quadratic		0.168	0.207	0.342	0.183

^a,bMeans in the same column without the same superscript differ significantly (P < 0.05).

Abbreviation: SEM, standard error of the mean.