Two experiments were conducted to evaluate the efficacy of cupric citrate (Cu-citrate) relative to cupric sulfate (CuSO4) as a Cu source for weanling and grow-finish pigs. In addition, the use of liver and bile Cu concentrations as indices of the bioavailability of Cu sources was investigated. Experiment one consisted of a nursery phase (35 d; initial BW=6.4 kg, final BW=21.4 kg) followed by a grow-finish phase (103 d; initial BW=21.5 kg, final BW=111.7 kg). Experiment two only consisted of a nursery phase (35 d; initial BW=6.3 kg, final BW=18.6 kg). Dietary treatments were identical for both experiments and consisted of: control (10 ppm CuSO4); control+66 or 225 ppm CuSO4; control+33, 66, or 100 ppm Cu-citrate. An antibiotic was included in diets for Exp. 1 but not Exp. 2. In both experiments, growth performance variables were similar for pigs receiving Cu-citrate and CuSO4; however, growth performance was not improved by high concentrations of CuSO4. Liver and bile Cu were increased (p<0.05) by 225 ppm CuSO4; however, lower dietary concentrations of Cu from either CuSO4 or Cu-citrate did not affect the Cu concentration of liver or bile relative to that observed in the control pigs. Irrespective of Cu source, there was no linear (p>0.10) increase in plasma Cu with increasing Cu concentrations in the diet for both experiments. However, the plasma Cu concentrations were highest (p<0.10) in pigs receiving diets supplemented with 225 ppm CuSO4. Sixteen randomly chosen pigs per treatment in Exp. 1 were continued through the grow-finish phase. Body weight gain and feed intake were improved (p<0.10) by 66 ppm CuSO4, but other dietary Cu treatments did not alter pig performance compared to the control diet. Plasma Cu concentrations were increased (p<0.10) by 225 ppm CuSO4 in the growing phase and by 225 ppm CuSO4 and 100 ppm Cu-citrate in the finishing phase. These data reveal no consistent effect of CuSO4 on performance; therefore, it is difficult to assess the efficacy of these two Cu sources. In addition, these studies demonstrate that liver and bile Cu are not good indicators of Cu bioavailability in pigs fed adequate to pharmacological concentrations of Cu.
Asian-Australasian Association of Animal Production Societies(AAAP)
Room 708 Sammo Sporex, 23, Sillim-ro 59-gil, Gwanak-gu, Seoul 08776, Korea TEL : +82-2-888-6558 FAX : +82-2-888-6559
E-mail : email@example.com