Table 2.

Effects of dietary selenium levels and sources on blood parameters of 17-d-old broiler chickens

Selenium source1	Selenium levels, mg/kg					Means	SEM2	P-value
	0.0	0.08	0.16	0.24	0.32			Source	Level	S X L3	L4	Q5
Glutathione peroxidase, U/L
Means	79.1 D	153 C	216 BC	266 AB	319 A		24.3	<0.01	<0.01	0.121	<0.01	0.406
SS	93.8 C	165 BC	240 AB	335 Aa	334 A	233					<0.01e	0.174
SY	62.8 C	126 BC	194 B	198 Bb	304 A	183					<0.01e	0.904
Superoxide dismutase, U/L
Means	98.7	88.9	92.1	81.9	92.9		7.17	0.524	0.647	0.394	0.647	0.243
SS	98.5	86.4	91.8	88.0	93.4	91.6					0.887	0.187
SY	98.9	91.5	92.5	75.8	92.3	90.2					0.420	0.549
Total T3, ng/ml
Means	3.32	2.30	3.01	2.51	2.73		0.125	0.419	0.056	0.134	0.278	0.241
SS	3.99 Aa	2.41 B	3.39 AB	2.59 AB	2.84 AB	2.87					0.136	0.018
SY	2.76 b	2.16	2.75	2.45	2.59	2.68					0.816	0.682
Free T3, ng/ml
Means	0.0056	0.0045	0.0059	0.0059	0.0054		0.0002	0.336	0.270	0.089	0.344	0.786
SS	0.0060	0.0042	0.0050 b	0.0060	0.0055	0.0053					0.648	0.163
SY	0.0052 AB	0.0048 B	0.0068 Aa	0.0059 AB	0.0053 AB	0.0056					0.343	0.091
Free T4, ng/ml
Means	31.6	36.4	38.8	32.9	35.9		0.942	0.416	0.050	0.403	0.627	0.140
SS	34.0	37.5	42.7	34.5	37.5	35.2					0.604	0.048e
SY	29.3	36.0	37.2	31.0	34.3	36.6					0.805	0.057e
Free T3:Free T46
Means	1.58	1.35	1.44	1.87	1.72		0.226	0.230	0.078	0.735	0.070	0.125
SS	1.60	1.36	1.28	1.79	1.53	1.51					0.575	0.531
SY	1.56	1.34	1.59	1.95	1.91	1.67					0.037	0.451

¹ SS sodium selenite, SY selenium enriched-yeast

² Standard error of means

³ Interactive effects between selenium and trace minerals sources and selenium levels

⁴ Linear effect of supplementation selenium levels

⁵ Quadratic effect of supplementation selenium levels

⁶ Free T3:Free T4 x 10000

^A-B Different uppercase letters in the same line and lowercase letters in the same column are different by Tukey test at 5%

^e Different superscripts letter indicates difference in the orthogonal contrasts between equations