Table 1.

Effects of dietary selenium levels and sources on performance traits 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
Initial weight, g/bird
SS	180.4	180.4	180.5	180.3	180.4	180.4	0.038	0.478	0.999	-	-	-
SY	180.2	180.3	180.1	180.3	180.2	180.2
Body weight, g/bird
Means	510	490	508	502	494		6.84	0.432	0.019	0.144	0.180	0.977
SS	514	487	497 b	500	498	499					0.378	0.104
SY	506 AB	492 AB	521 Aa	502 AB	490 B	502					0.308	0.088
Average daily gain, g/bird/day
Means	32.9 A	31.0 B	32.9 AB	32.1 AB	31.4 AB		0.672	0.429	0.017	0.132	0.165	0.977
SS	33.3	30.7	31.6 b	31.9	31.7	31.9					0.366	0.097e
SY	32.6 AB	31.3 B	34.1 Aa	32.2 AB	30.9 B	32.2					0.283	0.093f
Average daily feed intake, g/bird/day
Means	47.3	45.5	47.2	46.4	45.9		0.790	0.661	0.122	0.107	0.847	0.160
SS	48.5 a	45.6	46.1 b	46.4	46.0	46.6					0.090	0.122
SY	46.0 b	45.3	48.2 a	46.4	45.8	46.3					0.847	0.160
Feed conversion rate, g/g
Means	1.43	1.45	1.45	1.45	1.47		0.015	0.238	0.185	0.335	0.018	0.809
SS	1.44	1.46	1.46	1.46	1.45	1.46					0.661	0.449
SY	1.42 B	1.44 AB	1.44 AB	1.44 AB	1.48 A	1.44					0.004	0.616

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

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

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