One hundred and sixty weanling piglets with an initial average body weight (BW) of 7.3 kg were used in a 2×2 factorial experiment to investigate interactions between tetrabasic zinc chloride (TBZC) and copper sulphate (CuSO₄) on growth performance. In five piglets per treatment activity of enzymes in pancreas and digesta and short-chain fatty acids (SCFA) concentration in digesta were determined. The piglets were offered the following diets for 28 days: 1. no supplementation of TBZC and CuSO₄; 2. supplementation of 250 mg/kg Cu from CuSO₄; 3. supplementation of 1500 mg/kg Zn from TBZC; 4. supplementation of 1500 mg/kg Zn from TBZC and 250 mg/kg Cu from CuSO₄. Each treatment had five replications (pens) of eight piglets (half castrated males and half females). The results showed that average daily gain (ADG) was improved (P<0.05) by the addition of TBZC and (or) CuSO₄. The addition of TBZC increased (P<0.05) the activity of chymotrypsin in the duodenum contents (3.145 vs 2.095, respectively). TBZC and CuSO₄ synergistically reduced (P<0.05) pH of the jejunum contents. The addition of TBZC or CuSO₄ increased (P<0.05) total SCFA concentrations, and the proportion of acetic acid and propionic acid in the colon. TBZC reduced (P<0.05) the proportions of isobutyric acid (1.470 vs 1.830, respectively) and isovaleric acid (0.171 vs 0.203, respectively), but CuSO₄ increased (P<0.01) the proportions of isobutyric acid (1.904 vs 1.396, respectively) in the colon. There was a significant interaction between TBZC and CuSO₄ for ADG (P<0.01), for trypsin activities in both pancreatic tissue homogenates (P<0.01) and duodenal contents (P<0.05) and for chymotrypsin activities in both pancreatic tissue homogenate (P<0.05) and jejunum contents (P<0.01), and for total SCFA concentrations in the colon. These data indicated that the growth-promotional mechanisms of TBZC and CuSO₄ might be different.