Age and diet affect the composition of porcine colonic mucins.

Colonic mucins may serve as a defense mechanism by binding bacterial, viral, or dietary lectins, thereby preventing them from attaching to the intestinal epithelium. Presumably, the composition of the mucins would be responsible for this phenomenon, and the composition of mucins from mature mammals would be the most effective in binding lectins. To determine whether differences in diet and/or age affect the composition of colonic mucins, we scraped fresh colonic mucosae from pigs at 0 (n = 3), 7 (n = 3), 21 (n = 3), and 180 (n = 3) d of age and purified the mucins from these mucosal scrapings. Mucins were purified by ribonuclease and deoxyribonuclease digestion, high-performance size-exclusion chromatography, and cesium chloride density-gradient ultracentrifugation. The 180-d-old pig was considered mature. No changes were observed in any of the variables analyzed in the 7-d-old animals. No changes were observed in quantities of galactosamine and galactose. The amounts of fucose and glucosamine increased by 165 and 37%, respectively, (p < 0.05) from d 0 to d 21 in the sow-fed animals, at which time fucose and glucosamine content were 48 and 22% greater, respectively, than in the 21-d-old, artificially fed group (p < 0.05). A further significant increase in fucose content was observed in the mucins from mature animals. The sulfate content in the 21-d-old, sow-fed animals was significantly lower than in both the newborn and the 21-d-old artificially fed animals. The sulfate content in all three of these groups, however, was significantly higher than that observed in the mucins of mature animals.(ABSTRACT TRUNCATED AT 250 WORDS)