Table 7.

Effects of star anise oil on expressions of genes in liver of E. coli–challenged birds.¹

Items	SOD1	SOD2	HO-1	CAT	Nrf2	GPX-4
Treatment
Basal diet, unchallenged	1.000a,b	1.000a	1.000b	1.000a	1.000	1.000b,c
200 mg/kg of star anise oil, unchallenged	1.023a,b	1.079a	1.134a	1.014a	1.116	1.051b
400 mg/kg of star anise oil, unchallenged	1.075a	1.057a	1.126a	0.896b,c	1.359	1.217a
600 mg/kg of star anise oil, unchallenged	1.038a,b	0.831b,c	0.782d,e	0.798d,e	0.991	0.816d
Basal diet, challenged	0.656e	0.615e	0.819c,d	0.783e	0.849	0.796d,e
200 mg/kg of star anise oil, challenged	0.875c,d	0.865b	1.031b	0.860c,d	0.895	0.857d
400 mg/kg of star anise oil, challenged	0.964b,c	0.767c,d	0.885c	0.956a,b	1.220	0.961c
600 mg/kg of star anise oil, challenged	0.808d	0.706d	0.733e	0.827c-e	0.932	0.726e
SEM	0.031	0.027	0.026	0.023	0.031	0.025
Star anise oil
0	0.828	0.807	0.910	0.891	0.924c	0.898
200	0.949	0.972	1.083	0.937	1.005b	0.954
400	1.020	0.912	1.006	0.926	1.290a	1.089
600	0.923	0.768	0.758	0.812	0.962b,c	0.771
E. coli challenge
0	1.034	0.992	1.011	0.927	1.117a	1.021
+	0.826	0.738	0.867	0.856	0.974b	0.835
P values
Star anise oil	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001
Liner2	0.074	0.428	0.008	0.054	0.088	0.242
Quadratic2	0.005	0.004	<0.001	0.002	<0.001	<0.001
E. coli	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001
Star anise oil × E. coli	0.002	<0.001	0.004	<0.001	0.097	0.016

^a–eMeans within a row with different letters differ significantly (P < 0.05).

¹Data are means for 8 replicates per treatment.

²Liner and quadratic polynomial contrasts were performed on the means within the E. coli–challenged or unchallenged groups to star anise oil dosages.