Short communication: Copper bis-glycinate can partially or totally replace copper sulfate in diets with either no effects or positive effects on growth performance of weaned pigs

Abstract

An experiment was conducted to test the hypothesis that copper bis-glycinate (Cu-BisGly) can partially or fully replace copper sulfate (CuSO4) in diets for weanling pigs based on growth performance and fecal score. A total of 384 newly weaned pigs (26 d of age) with an average body weight of 7.59 ± 0.69 kg were allotted to 4 diets in a randomized complete block design. There were 6 pigs per pen and 16 replicate pens per diet. Dietary treatments included a treatment with 120 mg/kg Cu as CuSO4 (CuSO-120), 2 treatments with Cu as Cu-BisGly (Plexomin® Cu) at 60 or 120 mg/kg (Cu-BisGly-60 or Cu-BisGly-120), and a treatment with 120 mg/kg Cu from both Cu sources (60 mg/kg as CuSO4 and 60 mg/kg as Cu-BisGly; Combo). Experimental diets were provided in 2 phases with d 1–14 as phase 1 and d 15–28 as phase 2. Pig weights and feed left in feeders were recorded at the beginning and at the end of each phase. Fecal consistency score was recorded twice per week. Data for growth performance parameters and fecal score were calculated for each phase and for the entire experimental period, and were analyzed as a one-way ANOVA. Results indicated that in phase 1, there were no differences among treatments for average daily gain (ADG), average daily feed intake (ADFI), gain to feed ratio (G:F), or fecal score of pigs. In phase 2, pigs fed the CuSO-120 diet had lower (P < 0.05) ADG than pigs fed the Cu-BisGly-120 diet or the Combo diet. Pigs fed the Combo diet also had increased (P < 0.05) ADFI compared with pigs fed the CuSO-120 diet or the Cu-BisGly-60 diet. For the overall experimental period, pigs fed the Cu-BisGly-120 diet or the Combo diet had increased (P < 0.05) ADG compared with pigs fed the CuSO-120 or the Cu-BisGly-60 diet. In conclusion, 60 mg/kg of Cu-BisGly can replace 120 mg/kg of CuSO4 without adversely affecting growth performance or fecal score, but inclusion of 120 mg/kg of Cu-BisGly or a combination of 60 mg/kg of each Cu source results in improved growth performance of pigs.