Broiler responses to copper levels and sources: growth, tissue mineral content, antioxidant status and mRNA expression of genes involved in lipid and protein metabolism

Table 2 Growth performance of 17 d old broilers chicks fed different copper levels and sources

Item	Copper levels (mg/kg)					Source		SEM^a	Source	Level	Source × Level	L^b	Q^c
Item	0	4	8	12	16	Inorganic	Organic	SEM^a	Source	Level	Source × Level	L^b	Q^c
BW, g/bird	505	512	510	505	503	505	509	1.319	0.164	0.169	0.921	0.282	0.044
ADG, g/bird/day	33.7	34.4	34.3	33.8	33.5	33.7	34.1	0.132	0.159	0.172	0.923	0.283	0.045
ADFI, g/bird/day	44.4a	44.2ab	43.8 ab	43.1b	43.5ab	44.1	43.5	0.158	0.053	0.041	0.813	< 0.01	0.531
FCR, g/g	1.31a	1.28ab	1.27b	1.27b	1.30ab	1.31	1.27	< 0.01	< 0.01	0.013	0.953	0.077	< 0.01

Abbreviations: BW Body weight, ADG Average daily gain, ADFI Average daily feed intake, FCR Feed conversion ratio
^aStandard error of means
^bLinear effect of dietary copper levels
^cQuadratic effect of dietary copper levels
Organic: copper proteinate (CuPro) and organic trace minerals; Inorganic: copper sulphate (CuSO_4.5H₂O) and inorganic trace minerals
^a⁻^bMeans with a different superscript in a row are different (P < 0.05)

ISSN: 1746-6148