Table 6.

Effects of age and straw inclusion levels on antioxidant status of tissues from Yiling cull cows ¹.

Items 2	YCC		OCC		SEM	p-Value
	LRS	HRS	LRS	HRS		Age	Diet	Age × Diet
T-AOC (umol Trolox/Mgprot)
Liver	0.28	0.26	0.26	0.21	0.02	0.11	0.15	0.61
Muscle	1.17	1.25	1.12	1.18	0.10	0.55	0.48	0.91
CAT (U/mgprot)
Liver	4.78	3.85	3.29	3.28	0.45	0.045	0.33	0.34
Muscle	3.16	4.59	4.28	6.53	1.14	0.20	0.13	0.73
SOD (U/mgprot)
Liver	396	382	370	380	17.0	0.42	0.92	0.50
Muscle	1365	1189	1315	1178	52.5	0.57	0.01	0.71
ROS (U/mgprot)
Liver	13.2	12.9	13.6	13.2	0.62	0.57	0.63	0.99
Muscle	122.7	116.4	124.3	119.7	5.07	0.63	0.30	0.87
MDA (nmol/mgprot)
Liver	2.50	2.27	2.36	2.43	0.13	0.93	0.53	0.25
Muscle	17.2	16.7	15.9	16.5	0.99	0.43	0.97	0.59
PC (nmol/mgprot)
Liver	12.2	11.4	10.2	11.4	1.23	0.43	0.87	0.43
Muscle	53.4	66.9	57.2	45.3	7.37	0.25	0.92	0.11

¹ YCC, younger cull cows; OCC, older cull cows; LRS, providing 0.7 kg/d rice straw per head; HRS, providing 1.2 kg/d rice straw per head. ² T-AOC: total antioxidative capacity; CAT, catalase; SOD: superoxide dismutase; ROS, reactive oxygen species. MDA: malondialdehyde; PC: protein carbonyl.