Table 7. Effects of different dietary copper (Cu) sources and levels on serum characteristics in growing pigs (n = 6/treatment)

Cu source	Added Cu level (mg/kg)	GLU (mg/dL)	CREA (mg/dL)	BUN (mg/dL)	BUN/CREA	TP (g/dL)	ALB (g/dL)	GLOB (g/dL)	ALB/GLOB	ALT (U/L)	ALKP (U/L)	TBIL (mg/dL)	CHOL (mg/dL)
CuSO4	0	83.33	1.03	8.33	8.17	7.27ab	3.20	4.07a	0.80	72.67	170.00	0.42	75.83
	50	80.67	1.07	11.83	11.33	7.13ab	3.27	3.87ab	0.83	78.50	210.83	0.27	65.83
	100	77.17	1.05	11.50	10.83	7.32ab	3.13	4.18a	0.78	72.50	189.17	0.27	75.83
CuAA	0	83.33	1.03	8.33	8.17	7.27ab	3.20	4.07a	0.80	72.67	170.00	0.42	75.83
	50	83.17	1.03	10.50	10.33	7.12ab	3.05	4.07a	0.75	73.50	194.17	0.13	68.83
	100	85.00	0.97	10.67	11.67	7.53a	3.48	4.05a	0.87	64.00	201.83	0.48	77.67
CuHMB	0	83.33	1.03	8.33	8.17	7.27ab	3.20	4.07a	0.80	72.67	170.00	0.42	75.83
	50	82.50	1.05	9.00	8.67	6.93ab	3.30	3.63ab	0.90	88.67	170.50	0.30	77.50
	100	77.67	1.03	8.67	8.83	6.45b	3.23	3.22b	1.42	62.50	208.00	0.12	74.33
SEM		3.43	0.06	1.14	1.33	0.21	0.12	0.24	0.18	12.40	16.56	0.16	3.97
p-value for source × level		0.906	0.761	0.214	0.789	0.028	0.496	0.022	0.057	0.848	0.849	0.558	0.321
Main effect of source
CuSO4		80.39	1.05	10.56	10.11	7.24ab	3.20	4.04	0.81	74.56	190.00	0.32	72.50
CuAA		83.83	1.01	9.83	10.06	7.31a	3.24	4.06	0.81	70.06	188.67	0.34	74.11
CuHMB		81.17	1.04	8.67	8.56	6.88b	3.24	3.64	1.04	74.61	182.83	0.28	75.89
SEM		1.93	0.03	0.68	0.77	0.13	0.07	0.14	0.11	6.93	9.79	0.09	2.32
p-value for source		0.422	0.718	0.147	0.281	0.047	0.880	0.061	0.211	0.868	0.860	0.876	0.590
Main effect of level
	0	83.33	1.03	8.33	8.17	7.27	3.20	4.07	0.80	72.67	170.00	0.42	75.83
	50	82.11	1.05	10.44	10.11	7.06	3.21	3.86	0.83	80.22	191.83	0.23	70.72
	100	79.94	1.02	10.28	10.44	7.10	3.28	3.82	1.02	66.33	199.67	0.29	75.94
SEM		1.93	0.03	0.66	0.75	0.13	0.07	0.14	0.11	6.81	9.34	0.09	2.27
p-value for level		0.459	0.796	0.052	0.080	0.509	0.654	0.422	0.287	0.360	0.076	0.345	0.188

Values with different superscripts in the same column are significantly different (p < 0.05).
GLU, glucose; CREA, creatinine, BUN, blood urea nitrogen; TP, total protein; ALB, albumin; GLOB, globulin; ALT, alanine aminotransferase; ALKP, alkaline phosphatase; TBIL, total bilirubin; CHOL, cholesterol; CuSO₄, copper sulfate; CuAA, Cu-amino acid complex; CuHMB, Cu-hydroxy-4-methylthio butanoate chelate complex.