Abstract
The objective of this study was to investigate effects of a low dietary dose of coated CuSO(4) and ZnO on growth performance, frequency of diarrhea, nutrient digestibility, immune responses, and fecal microbiota of weaned pigs. In a randomized complete block design (block: initial body weight), a total of 96 weaned pigs [Landrace × Yorkshire) × Duroc; 7.29 ± 0.69 kg of average initial body weight (BW)] were allotted into four dietary treatments (4 pigs/pen, 6replicates/treatment): (1) a basal weaner diet based on corn and soybean meal (CON), (2) CON supplemented with 2,500 ppm standard ZnO (T1), (3) CON supplemented with 100 mg/kg dietary coated CuSO(4) and 100 mg/kg dietary coated ZnO (T2), and (4) CON supplemented with 200 mg/kg dietary coated CuSO(4) and 200 mg/kg dietary coated ZnO (T3). Dietary T2 and T3 increased (p < 0.05) the average daily gain for the first two weeks and the overall experimental period compared to that with CON. In addition, the groups supplemented with CuSO(4) and Zno tended to have a decreased (p < 0.10) frequency of diarrhea. Pigs fed dietary T2 and/or T3 had lower (p < 0.10) the number of white blood cells on day 7 and hematocrit on day 14 compared to those fed CON. However, no difference was observed in the number of red blood cells among the dietary treatments. Regarding immune responses, dietary T2 decreased (p < 0.10) serum tumor necrosis factor-α level on day 7 and increased (p < 0.10) immunoglobulin G level on day 14 compared with CON. Moreover, pigs fed dietary T2 tended to have increase bacterial abundance of Limosilacatobacilus (p < 0.10) compared with those fed dietary T1. Dietary T3 had higher (p < 0.05) relative abundance of the genus Agathobacter compared to those fed CON and dietary T1 and decreased (p < 0.05) genus Terrisporobacter compared to those fed dietary T1. These results suggested the supplementation of dietary coated ZnO and CuSO(4) enhanced growth performance and modulated immune responses associated with changes in the fecal microbiota composition.