Table 4.

Effect of dietary Se yeast supplementation on the biochemical and the antioxidant indices in plasma of Longyan laying ducks (n = 6)^a.

Items	Supplemented Se level from Se yeast, mg/kg				SEM	P-values
	0	0.05	0.15	0.25		Treatment	Linear	Quadratic	Cubic
TP, mg/ml	5.54	5.59	5.20	5.22	0.176	0.424	0.177	0.755	0.458
ALB, mg/ml	1.54	1.50	1.37	1.34	0.163	0.846	0.433	0.857	0.917
GLB, mg/ml	4.00	4.10	3.83	3.88	0.278	0.941	0.675	0.926	0.679
ALB/GLB ratio	0.407	0.378	0.427	0.350	0.074	0.991	0.845	0.855	0.964
ALT, U/L	3.07	3.13	3.02	3.17	0.303	0.993	0.911	0.863	0.819
AST, U/L	2.73	2.75	2.36	2.05	0.347	0.576	0.175	0.863	0.813
GSH-Px, mmol/ml	173c	274b	365a	272b	6.5	<0.001	<0.001	<0.001	0.393
SOD, U/ml	22.2	22.8	25.1	26.3	4.61	0.910	0.478	0.956	0.939
CAT, U/ml	1.71c	2.51bc	3.28ab	3.90a	0.376	0.003	<0.001	0.470	0.712
TAC, U/ml	3.53c	5.65b	10.6a	5.61b	0.251	<0.001	<0.001	<0.001	<0.001
MDA, nmol/ml	32.8a	23.4b	18.8c	22.5b	0.38	<0.001	<0.001	<0.001	<0.001
MDA/TAC ratio	9.55a	4.16b	1.78b	4.03c	0.373	<0.001	<0.001	<0.001	0.0152

Se yeast, selenium-enriched yeast; SEM, standard error of the mean; TP, total protein; Alb, albumin; Glb, globulin; ALT, alanine transaminase enzyme; AST, aspartate transaminase enzyme; GSH-Px, glutathione peroxidase; SOD, superoxide dismutase; CAT, catalase; TAC, total antioxidant capability; MDA, malondialdehyde.

^aMeans were calculated using six replicates per treatment (one bird per replicate).

^{a, b, c}Mean values within a row with different letters were significantly different (p < 0.05).