An experiment was carried out to evaluate high dietary levels of organic and inorganic Cu, respectively, cupric citrate (C6H4Cu2O7 ) and Cu sulfate (CuSO4.5H2O) as growth promoters of weanling pigs fed complex diet. Eighty crossbred weanling pigs (40 castrated males and 40 females), averaging 6.85 kg initial weight and 21 ± 2 days of age, were assigned to five treatments. The treatments consisted in a basal diet (control) of corn, soybean meal, lactose, dried skim milk and spray dried porcine plasma meal, or the basal diet supplemented with 200 ppm of inorganic Cu (Cu sulfate), or 50, 100, and 150 ppm of organic Cu (cupric citrate). The basal diet was supplemented with 2,500 ppm of Zn (ZnO) during the first 14 days of experimental period. Pigs were housed in 20 elevated metal pens (1.50 x 1.20 m), which were cleaned, disinfected and kept unused for 90 days before the experiment. Feed and water were given ad libitum during all 28-day experimental period. A randomized complete block design was used with five treatments, four replications per treatment, and four pigs (two castrated males and two females) per pen (experimental unit). High dietary levels of copper did not affect average daily gain, daily feed intake and feed conversion of the pigs. Therefore, high dietary levels of organic Cu (cupric citrate) and inorganic Cu (Cu sulfate) did not show any growth promoter effect on weanling pigs fed complex diet in a clean nursery room.
copper citrate; organic copper; inorganic copper; nursery room; complex diet; growth promoter; copper sulfate
