Different sources and dosages of zinc oxide and copper influence growth performance and intestinal health of post-weaning piglets

In pig production, weaning is a critical period where piglets face several environmental stressors. This transition leads to a significant growth reduction and can result in digestive disorders, including diarrhea. To formulate a feed that meets zinc (Zn) and copper (Cu) requirements during the weaning period while minimizing their release into the environment, it became evident that a more bioavailable micro-mineral supplement is necessary. This project aimed to evaluate two sources of Zn (standard oxides and potentiated oxide (ZnO)) and Cu (sulphate and monovalent Cu), on the growth performance, intestinal health (inflammation, barrier function, mucosal stress), and microbiota abundance and composition of weaned piglets. At weaning (21 days), 135 piglets were selected. The experimental diets were composed as follows: basal diet with the addition of: 1) Negative control (NC): 150 mg/kg ZnO and 150 mg/kg Cu (sulphate); 2) Positive control (PC): 2,600 mg/kg ZnO and 150 mg/kg Cu (sulphate); 3) SpEU: 150 mg/kg potentiated form of ZnO (HiZox®) and 150 mg/kg monovalent Cu oxide (CoRouge®); 4) SpCA: 300 mg/kg potentiated ZnO and 150 mg/kg monovalent Cu. The experimental diets were provided for 14 days (phase 1) post-weaning. Subsequently, all piglets received the same diets for phase 2 (14-28 days) and phase 3 (28-42 days). Piglets were weighed at weaning and on days (d) 14, 28, and 42. At d7 and d14, blood was collected for intestinal health status marker analyses. At d14, fecal samples were collected to assess the effects on microbiota, calprotectin, and neopterin. In the first phase, average daily gain (ADG) and average daily feed intake (P = 0.001) resulted in higher outcomes in the PC group. Feed conversion was higher in the SpEU and SpCA groups (P = 0.002). For the overall performance, however, highest ADG were observed in both the PC and SpCA groups (P = 0.001). The citrulline was found to be higher in the NC group (P = 0.002). The diamine oxidase was higher in SpCA than PC group (P = 0.008). Zinc concentrations in feces and serum were higher for PC treatment (P = 0001, P = 0.037, respectively). From the results it was possible to confirm the positive effects of the administration of 300 mg/kg of the potentiated ZnO and 150 mg/kg monovalent copper oxide could be a valid substitute of pharmacological ZnO.