Copper Super-Dosing Improves Performance of Heat-Stressed Broiler Chickens through Modulation of Expression of Proinflammatory Cytokine Genes

Table 3

Performance traits of broiler chickens supplemented with incremental doses of copper (as yeast protein) during 1–35 d¹.

Parameters		Added Cu proteinate in diet mg/kg diet (added Cu mg/kg diet)					Pooled SEM	value
		0 (0)	250 (37.5)	500 (75)	750 (112.5)	1000 (150)		Linear	Quadratic
Body weight (g)	0 d	48.9	49.0	48.9	49.1	48.9	0.03	0.628	0.105
	21 d	969.2^a	1029.4^b	1048.0^b	1053.1^b	1069.6^b	4.64	0.0001	0.013
	35 d	1878.4^a	1958.3^ab	1989.9^b	2015.9^b	2026.9^b	9.25	0.0001	0.089
Gain (g/d)	1–21 d	43.82^a	46.69^b	47.58^bc	47.81^bc	48.6^c	0.22	0.0001	0.013
	22–35 d	64.94^a	66.34^b	67.27^bc	68.77^bc	68.37^c	0.64	0.029	0.537
	1–35 d	52.27^a	54.55^b	55.45^bc	56.19^bc	56.51^c	0.26	0.0001	0.089
Feed intake (g/d)	1–21 d	58.3	58.7	59.5	59.5	57.7	0.28	0.689	0.474
	22–35 d	120.1^a	122.3^ab	122.6^ab	123.7^ab	126.9^b	0.75	0.001	0.858
	1–35 d	83.0^a	84.1^ab	84.7^ab	85.2^b	85.4^b	0.29	0.0001	0.819
Feed: gain^2	1–21 d	1.330^c	1.257^b	1.250^b	1.246^b	1.189^a	0.005	0.0001	0.004
	22–35 d	1.850	1.845	1.823	1.805	1.860	0.011	0.866	0.381
	1–35 d	1.589^b	1.543^a	1.528^a	1.518^a	1.512^a	0.005	0.0001	0.007
Liveability (%)	1–35 d	96.25	100	97.5	97.5	98.75	0.64	0.585	0.644

¹Means of 8 replicate pens/treatment with n = 10 birds/replicate at the beginning of the experiment; ²corrected for mortality; means with dissimilar superscripts in a row varied significantly.