LONG-TERM EFFECTS OF DIETARY COPPER SOURCE AND LEVEL ON PERFORMANCE AND HEALTH OF SOWS AND PIGLETS

OF DISSERTATION LONG-TERM EFFECTS OF DIETARY COPPER SOURCE AND LEVEL ON PERFORMANCE AND HEALTH OF SOWS AND PIGLETS The objectives of this study were to investigate the long-term effects of feeding increasing supplemental levels (20, 120, or 220 mg/kg) of dietary copper (Cu) as tribasic copper chloride (TBCC) or copper sulfate (CuSO4) on performance, antioxidant status, nutrient digestibility, and trace mineral deposition of sows and piglets; as well as to assess nursery dietary Cu levels on growth performance and response to immunological challenge in nursery pigs from sows fed either high or low Cu diets. In the long-term sow experiment, sows fed TBCC diets had greater adjusted weaning weight for litter and piglet (P < 0.10), as well as adjusted litter and piglet weight gain (P < 0.10) when compared to sows that received CuSO4 diets. Increasing dietary Cu level linearly increased live born piglet weight (P = 0.06). Sows fed TBCC diets had lower apparent total tract digestibility (ATTD) of ether extract (P = 0.01) during late gestation, but greater ATTD of dry matter, nitrogen, and phosphorous during lactation (P < 0.05). Increasing Cu levels linearly increased dry matter digestibility in lactating sows (P = 0.02). Milk from sows fed TBCC diets had a greater concentration of protein (P = 0.02) than that from sows fed CuSO4 diets. Increasing Cu levels increased levels of milk fat and Cu (linear, P < 0.05); but linearly decreased lactose and Zn levels (P < 0.05). Lactating sows fed TBCC diets had a greater activity of Cu/Zn superoxide dismutase (SOD) and ceruloplasmin in serum than those fed CuSO4 diets (P < 0.05). Increasing dietary Cu levels increased total and Cu/Zn SOD activity for lactating sows (linear, P < 0.05). Sows fed TBCC diets had lower concentrations of Cu (P = 0.04), but higher concentrations of iron and manganese (P < 0.05) in the liver, when compared to those fed with CuSO4 diets. In addition, liver Cu concentrations increased with increasing dietary Cu levels (linear and quadratic, P < 0.05). Increasing dietary Cu levels resulted in the elevation of concentrations and contents of Cu in the liver of weanling piglets (linear, P < 0.0001). In the nursery pig experiment, pigs from sows fed 120 mg/kg Cu diets had greater ADG from d 0 to 14 (P < 0.05), and tended to have greater ADG in the overall period (P < 0.08), when compared to pigs from sows fed 20 mg/kg Cu diets. During the lipopolysaccharide challenge period, the challenged pigs from sows fed 120 mg/kg Cu had a greater overall rectal temperature than those from sows fed 20 mg/kg Cu (P = 0.01). Also, the challenged pigs fed with 220 mg/kg Cu diets had greater serum tumor necrosis factor-alpha concentration over time as compared to those fed 20 mg/kg Cu diets (P = 0.03). In summary, the TBCC may be a superior Cu source compared to CuSO4 regarding reproductive performance, and higher dietary Cu levels result in greater birth weight of piglets; furthermore, high Cu levels in sow and nursery diets promote growth performance of nursery pigs and affects their responses to immunological challenge.