Probiotics have become highly recognized as supplements for poultry.Since gut health can be considered synonymous withanimal health, the effects of probiotic Slab51 on the morphology and the glycan composition of guineafowlintestine were examined. The probiotics were added in drinking water (2 × 10 UFC/L) throughout the grow-out cycle.Birds were individually weighed andslaughtered after four months. Samples from the duodenum, ileum and caecum were collected and processed for morphological, morphometric, conventional and lectin glycohistochemical studies.The results were analyzed for statistical significance by Student's test. Compared with control samples, probiotic group revealed (1) significant increase in villus height ( < 0.001 in duodenum and ileum; < 0.05 in caecum), crypt depth ( < 0.001 in duodenum and caecum; < 0.05 in ileum) and goblet cells (GCs) per villus ( < 0.001) in all investigated tracts; (2) increase in galactoseβl,3N-acetylgalacyosamine(Galβl,3GalNAc)terminating O-glycans and αl,2-fucosylated glycans secretory GCs in the duodenum; (3) increase in α2,6-sialoglycans and high-mannose N-linked glycans secretory GCs but reduction in GCs-secreting sulfoglycans in the ileum; (4) increase in Galβl,3GalNAc and high-mannose N-linked glycans secretory GCs and decrease in GCs-producing sulfomucins in the caecum; (5) increase in the numbers of crypt cells containing sulfate and non-sulfated acidic glycans. Overall, dietary Slab51 induces morphological and region-specific changes in glycoprotein composition of guinea fowl intestine, promoting gut health.