Optimal dietary copper requirements and relative bioavailability for weanling pigs fed either copper proteinate or tribasic copper chloride

Table 9 Estimation of dietary Cu requirements for weanling pigs fed diets with TBCC or CuPro based on broken-line regression analysis

Dependent variables	Copper source¹	Regression equation²	RMSE³	Dietary Cu requirement⁴, mg/kg
ADG	TBCC	Y = 357.15–0.420 × (X < 140.65) × (140.65 − X)	18.03	140
ADG	CuPro	Y = 361.37–0.800 × (X < 80.00) × (80.00 − X)	30.20	80
FCR	TBCC	Y = 1.445 + 0.0018 × (X < 119.93) × (119.93 − X)	0.023	120
FCR	CuPro	Y = 1.423 + 0.0030 × (X < 73.81) × (73.81 − X)	0.022	74
ALP	TBCC	Y = 2.973–0.009 × (X < 148.33) × (148.33 −X)	0.144	148
ALP	CuPro	Y = 3.048–0.014 × (X < 97.55) × (97.55 − X)	0.122	98
Bile Cu	TBCC	Y = 3.216–0.0267 × (X < 93.38) × (93.38 − X)	0.207	93
Bile Cu	CuPro	Y = 3.228–0.0360 ×(X < 69.10) × (69.10 − X)	0.269	69
CER	TBCC	Y = 84.58–0.252 × (X < 50.00) × (50.00 − X)	3.73	50
CER	CuPro	Y = 85.92–1.079 × (X < 26.50) × (26.50 − X)	5.32	27
Cu/Zn SOD	TBCC	Y = 146.03–0.194 × (X < 102.67) × (102.67 − X)	12.58	103
Cu/Zn SOD	CuPro	Y = 152.33–0.473 × (X < 62.72) × (62.72 − X)	11.94	63
GSH-Px	TBCC	Y = 748.73–0.272 × (X < 75.59) × (75.59 − X)	3.71	76
GSH-Px	CuPro	Y = 757.54–0.337 × (X < 88.37) × (88.37 − X)	4.84	88
MDA	TBCC	Y = 1.81 + 0.0070 × (X < 84.87) × (84.87 − X)	0.279	85
MDA	CuPro	Y = 1.77 + 0.0116 × (X < 49.80) × (49.80 − X)	0.20	50
T-AOC	TBCC	Y = 0.709–0.0010 × (X < 105.12) × (105.12 − X)	0.141	105
T-AOC	CuPro	Y = 0.711–0.0012 × (X < 77.67) × (77.67 – X)	0.101	78

¹TBCC tribasic copper chloride, CuPro copper proteinate
² Y is the dependent variable and X is the supplementation Cu concentration in the corresponding diet (mg/kg)
³ RMSE: root mean squared error
⁴ Dietary Cu requirement = Supplemental Cu level
ALP alkaline phosphatase, CER ceruloplasmin, Cu/Zn SOD Cu, Zn-superoxide dismutase, GSH-Px glutathione peroxidase, MDA malondialdehyde, T-AOC total antioxidant capability

ISSN: 2049-1891