Immunohistochemical study on the ontogenetic development of the regional distribution of peptide YY, pancreatic polypeptide, and glucagon-like peptide 1 endocrine cells in bovine gastrointestinal tract

► Different frequencies of PYY, PP and GLP-1 cells were found in the bovine intestines at seven ontogenetic stages. ► The frequency of these cells were decreased from the fetus stage to cow. ► These changes might be correlated with the nutritional adaptation of ruminants at specific ontogenetic stages.