Effects of zinc and copper levels on growth performance of nursery pigs.

A 20-d experiment was conducted to evaluate the effects of added Zn and Cu on growth performance of nursery pigs. Treatments were arranged in a 2 × 2 factorial treatment structure with main effects of added Zn (100 or 3,000 mg/kg of diet) and Cu (10 or 200 mg/kg of diet). Basal Zn and Cu levels (100 and 10 mg/kg, respectively) were from organic sources, while the added high levels (2,900 and 190 mg/kg, respectively) were from Zn oxide and Cu hydroxychloride. A total of 784 pigs (PIC 337 × Camborough), initially 6.0 kg, were used with 7 replicates per treatment. Experimental diets were corn, soybean meal, and whey permeate-based and contained 1.38% SID Lys. Pigs were weighed and feed disappearance measured to calculate ADG, ADFI, and G:F. Data were analyzed with SAS MIXED procedure. From d 0 to 10, there was no evidence (P > 0.10) for interactive or main effects of Zn or Cu. From d 10 to 20 and overall (d 0 to 20), there was an interaction (P < 0.05) between Zn and Cu for G:F. From d 10 to 20, pigs fed 10 mg/kg added Cu had improved G:F when 3,000 mg/kg added Zn was fed; however, pigs fed 200 mg/kg added Cu had similar G:F regardless of added Zn level. There was no evidence (P > 0.10) for interaction for ADG or ADFI, indicating an additive Zn and Cu effect. Feeding 3,000 mg/kg added Zn or 200 mg/kg added Cu improved ADG, ADFI, and final BW with the highest performance observed when feeding both 3,000 mg/kg added Zn and 200 mg/kg added Cu. In summary, feeding high levels of Zn or Cu did not impact the first 10-d postweaning performance, but Zn and Cu effects were observed in the subsequent 10-d and overall performance. [ABSTRACT FROM AUTHOR]