Polyamine metabolism in the intestine of piglets is altered by weaning and proline supplementation

Polyamines are essential for the proliferation and differentiation of the rapidly renewing intestinal mucosa. The object of this study was to investigate polyamine metabolic profiles in the intestinal mucosa of piglets during the suckling and postweaning periods and under treatment with proline. Intestinal mucosa samples were obtained from 1-, 7-, 14-, and 21-d-old suckling piglets and piglets on Days 1, 3, 5, and 7 postweaning at 14 d of age, as well as from piglets that received the oral administration of proline from Day 1 to 14. During the suckling period from Day 1 to 21, higher concentrations of spermine and tyramine in the jejunal mucosa and putrescine, spermidine, and tyramine in the colonic mucosa were observed on postnatal Day 1 compared with other days (P < 0.05). Weaning at age 14 d induced an increase in the contents of tyramine in the jejunal mucosa and of spermine in the colonic mucosa but a decrease in 1,7-hepthyl diamine in the colonic mucosa on Days 1, 3, and 5 postweaning (P < 0.05). The mRNA and protein expression of ornithine decarboxylase (ODC) in three segments of the intestine were increased from Day 1 to 21, and a sharp increase was observed on Day 3 postweaning (P < 0.05). Oral administration of proline increased the concentrations of spermidine and spermine in the ileal mucosa and ODC protein expression in the three segments of the intestine (P < 0.05). These findings indicated that polyamine metabolism and ODC expression were altered by weaning and proline administration and may be useful as a marker of intestinal growth and restitution.