The effect of supplementing the standard piglet diet containing sodium butyrate with glutamine and/or glucose on the structure of the piglet digestive tract and the small intestine epithelium, acidity and volatile fatty acid content of its digesta was investigated. The free amino acids level, insulin and insulin-like growth factor-1 (IGF-1) concentration in the blood were also analysed. The experiment was performed on 156 piglets (15 litters) allocated to 5 experimental groups, 3 litters in each. Group I (C, negative control) received a basal mixture with no supplement. Group II (SB, positive control) was fed the same basal diet containing additionally 3 g of sodium butyrate per kg. Group III and IV, besides sodium butyrate, received additionally 10 g of glutamine (GT) or glucose (GC), respectively. The last group V received all these supplements, i.e. SB+GT+GC (3, 10, 10 g per kg, respectively). At 60 days of age, the piglets (6 animals from each group) were slaughtered and their intestines were measured and weighed. The piglets in group SB+GT+GC receiving all the supplements grew slightly faster than the others, and at the end of the experiment the differences in body weight were significant. The total intestinal mass of the piglets fed with glucose or all the supplements was significantly higher than that of the piglets receiving glutamine but there was no significant difference in the total length of intestines. There was also no significant difference in acidity of chyme along the entire length of the gastrointestinal tract. Digesta in the jejunum of both control groups (C, SB) contained significantly more SCFA than the remaining groups. In the caecum their content in the negative control and the group fed with all supplements was significantly higher when compared to the butyrate and glucose group. In the duodenum villus height was similar in all the groups but in the jejunum it was significantly higher in the group receiving all supplements than in other groups. Free amino acids level was lowest in the piglets receiving glucose but there was no difference between the remaining groups. The lowest level of IGF-1 was found in the same group and this difference was significant when compared with remaining groups, except C. It is concluded that glutamine and glucose, when given together with sodium butyrate, improve the structure of piglet jejunum epithelium and average body weight gains. A supplement of glucose significantly lowers free amino acid content and IGF-1 level in piglet blood.