Table 4.

Effect of dietary astaxanthin (ASTA) supplementation on antioxidant enzyme activities and lipid peroxidation levels in the liver of laying hens.

Items	ASTA levels/(mg/kg)				SEM	P value
	0	25	50	100		Linear	Quadratic
GSH-Px (U/mg prot)	24.36d	29.11c	37.97a	31.68b	1.07	<0.01	<0.01
MDA (nmol/mg prot)	0.80a	0.63a,b	0.58b	0.57b	0.023	<0.01	0.12
SOD (U/mg prot)	268.97c	315.02b	369.55a	318.76b	7.77	<0.01	<0.01
T-AOC (U/mg prot)	0.034c	0.038b	0.048a	0.037b,c	0.0012	<0.01	<0.01

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

Abbreviations: GSH-Px, glutathione peroxidase; MDA, malondialdehyde; SOD, superoxide dismutase; T-AOC, total antioxidant capacity.