Table 5.

Effects of dietary addition of Echinacea purpurea polysaccharides (EP) on antioxidant capacity of broilers.

Items	Age, d	Groups1				SEM	P-value
		CON	EPL	EPM	EPH		ANOVA	Linear	Quadratic	EPs × age
T-AOC, mmol/mL	21	0.76b.A	0.84abA	1.01ab	1.05a	0.043	0.031	0.003	0.011	0.710
	42	0.59bB	0.62bB	0.72ab	0.79a	0.026	0.013	<0.001	0.004
GSH-Px, U/mL	21	1235B	1441B	1239B	1294B	40.323	0.241	0.462	0.565	0.126
	42	3858abA	3360bA	3949aA	3460abA	89.604	0.026	0.533	0.793
MDA, nmol/mL	21	7.32a	4.78b	5.56bA	4.60bA	0.285	0.001	0.005	0.012	0.051
	42	6.31a	4.71ab	3.19bB	3.60bB	0.317	<0.001	<0.001	<0.001

T-AOC = total antioxidant capacity; GSH-Px = glutathione peroxidase; MDA = malondialdehyde; CON = control; SEM = standard error of the mean.

Different lowercase letter superscripts in the same row indicate significant differences among EP addition levels (0.0, 0.3%, 0.6%, and 0.9%) (P < 0.05). Different uppercase letter superscripts within the same column indicate significant differences between age stages (21 and 42 d) (P < 0.05); EPs × age denotes the interaction between EP addition levels and ages.

¹CON, EPL, EPM, and EPH, represent EP addition levels of 0.0, 0.3%, 0.6%, and 0.9% in the diet, respectively (n = 6).