Aim This study was carried out to investigate the effects of dietary calcium pyruvate supplementation on growth performance and intestinal health of weaned piglets fed low-protein diets. Methods and results After a 7-day adaptation period, 60 individually housed piglets (Duroc x Yorkshire-Landrace) weaned at 28 days of age were randomly assigned to receive one of three treatments (20 pigs/treatment) for 28 days: control diet (20 center dot 0% crude protein [CP]), low-protein diet (15 center dot 5% CP), and experimental (15 center dot 5% CP + 1 center dot 8% calcium pyruvate). At the end of the experiment, six piglets from each diet group were slaughtered and blood and tissue samples were collected. Compared with the control group, feeding piglets with 15 center dot 5% CP decreased the daily body weight gain; lengths of the duodenum, jejunum and ileum; and weights of the stomach, duodenum, jejunum and ileum (P < 0 center dot 05), while 15 center dot 5% CP + 1 center dot 8% calcium pyruvate supplementation removed those differences (P > 0 center dot 05). Compared with the control group, the diarrhoea incidence and relative richness of Firmicutes in the colon contents of piglets in both the 15 center dot 5% CP and 15 center dot 5% CP + 1 center dot 8% calcium pyruvate groups was decreased. The relative richness of Bacteriodetes in the colon contents of piglets was higher in the 15 center dot 5% CP + 1 center dot 8% calcium pyruvate group than in the control and 15 center dot 5% CP groups (P < 0 center dot 05). Conclusion Calcium pyruvate supplementation for four weeks removed the negative effects of a low-protein diet on the gastrointestinal tract development and daily body weight gain of weaned piglets. Significance and impact of the study This study showed that supplementing a low-protein diet with calcium pyruvate, an effective alternative metabolic fuel to amino acids, was beneficial in improving the intestinal health and maximizing the growth of newly weaned piglets.